Air conditioners, once considered a luxury afforded only by the wealthy, have in recent years, become an affordable option for many. Advancements in technology and design have driven down their installation and running costs, and increased their popularity. Here in the UK, following soaring summer temperatures, there has been an unprecedented demand.

The installation of an air conditioner is, of course, a considerable expense, and the ongoing costs will also need careful consideration. In this article we help you get an understanding of what factors impact the cost to run them.


With recent rises in energy prices, without a doubt, this is one question that every prospective customer will ask.  However, this is not a straightforward question which we can answer precisely. There are many variables that affect the running cost of you AC unit, and these we will discuss in more detail below. The following table will give you a rough idea of typical hourly costs per unit size.

Unit Size Hourly cost


Another question that does not have a cut and dry answer, as this will vary with each manufacturer.  For an accurate answer, be sure to check with the contractor installing your system or the electrician providing the power supply service. Below is a simple table that gives you an idea of how much power an AC system uses.  The suggested fuse size is the unit’s maximum draw.

Suggested Fuse rating in AMPS for a split wall mounted system


The running costs of an air conditioner will vary according to its type and size (by size we are not referring to physical size, but output). Most people appreciate that the longer their air conditioner is operating, the higher their electricity bills will be, and in this day and age, when we are very environmentally conscious, there is another good reason to be mindful of the energy that we are using too.

Thankfully there are simple steps that you can take to make sure that your air conditioner operating as efficiently as it possibly can, this will help you to keep your energy usage low when temperatures rise.

Insulation …

Most people associate insulation with keeping the heat in during the winter months however creating a thermal barrier with insulation does a fantastic job of keeping the summer heat out too! If your house is well insulated, you will find that you do not need to have your air conditioner operating constantly, and it will not have to work so hard to keep your room at the correct temperature. So, whether you are using your air conditioner to cool or heat your home, ensuring that your home is well insulated makes good financial sense.

Have regular service and maintenance …


The regular servicing of your air conditioning system will increase its efficiency and lifespan, reduce running costs, and help to keep your energy bills low. Depending on your system and its use, generally speaking a domestic unit will require a service visit once a year, and a commercial system twice a year.

It is possible in some instances to clean the filters and fans yourself, but it is recommended that you enlist a professional to carry out a thorough service, to keep your system functioning properly. An experienced engineer will be able to detect any early signs of a faulty component and will be able to repair or replace it avoiding a costly emergency breakdown.

Installation costs compared to running costs …

Don’t be tempted to install the cheapest air conditioner, as although you may be saving on installation costs they are often less efficient and therefore far more expensive to run. An inverter air conditioner uses a variable speed compressor which speeds up and slows down as required to maintain room temperature. In simple terms as the system never actually powers off, it doesn’t waste huge amounts of energy constantly powering on and off like a non inverter system. Although they are more expensive to install inverter systems are far more efficient, more effective and have a longer life span than non inverter systems.

Consider unit size …

To keep your running costs low you will need to calculate the correct unit size for the area. One that’s too small will not heat or cool your room effectively, and one that’s oversized will be inefficient, expensive to run and costly to repair.

Take control of your unit …

Take the time to get to know your system energy saving features. A well controlled system will certainly be easier on the pocket, so make sure you read your AC manuals carefully. Modern day air conditioners have high spec features such as WIFI enabled systems allowing total temperature via a smartphone app, or even voice control using Alexa or Google Home, so that you can customize your heating and cooling settings, review your consumption and ensure that you air conditioner is being used only when it is needed.

Choose the right air conditioner for your needs ….

Make sure you have the right air conditioner for the job! Sounds obvious but there are many different heating and cooling options out there for you to choose from. From single wall mounted unit to complex multi split systems, your expert AC installer will find the perfect energy efficient solution for your individual needs.

Review your energy supplier…

Shop around to make sure you are getting the best deal. With prices set to rise, there has never been a better time to review how much you are paying and choose who is supplying your energy.


How can I reduce the running cost of my air conditioner?

This question has been answered in more detail in the above article but key considerations are: check that your building is insulated, carry out regular service and maintenance, upgrade to an more energy efficient system, check that unit is correct size and ensure unit is controlled effectively.

How can I reduce my carbon footprint from my AC system?

This article highlights ways to reduce the running costs of your air conditioner. By following these easy steps you will be helping to reduce your energy usage and in turn your carbon footprint. If you would like to find out more information on whether air conditioning is bad for the environment and what you can do to help reduce global warming please click here.

How can I monitor the running costs of my air conditioning system?

By connecting your air conditioner to your home wifi network, it is easy to remotely control your thermostat, set temperature schedules, and keep an close eye on your energy consumption. Download the app to your smartphone that corresponds to your manufacturer or alternatively use voice control via Alexa or Google Home.

Is air conditioning expensive to run?

This is a difficult question to answer simply as air conditioners can be considerably expensive to run especially if your house is poorly insulated, your system is incorrectly sized, poorly maintained or your energy tariff is too high. However, an air conditioner is a highly efficient at cooling and heating which doesn’t need to be heavy on your wallet if you ensure that your take the advice given in this article.

Evergreen provide AC services to suit all budgets and applications. For expert advice on installation, maintenance, or emergency repair of an AC system in your home please contact our specialist team.


In this article we discuss why the installation of an air conditioner could be a wise choice when considering the environment. We also look at global warming, how it is affecting us, and what positive changes we can make to reduce our impact.


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Climate change is the single most serious threat facing our planet today. Left unchecked, humans and nature will experience extreme weather, worsening droughts, rising sea levels and mass extinction of species. Unless we act now, global warming is set become more severe and widespread, and will have devastating consequences for our future generations.

The responsibility lies squarely on our shoulders to protect our Earth, as human activity has been the main driver of climate change. Everything we do in our day-to-day life has an impact on the planet. We all need to make wiser choices to live more sustainably and dramatically reduce our production of greenhouse gases if we stand a chance of limiting the damage that rising global temperatures will cause.


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Whether you are cutting down on plastic, cycling to work or eating less meat your contributions to the cause may feel small, but collectively we can make a huge difference to climate change.

With energy prices set to unprecedently rise, there has never been a better time to consider where you are getting your energy from. One quarter of human made greenhouse gas emissions come from burning fossil fuels for electricity and heat production.

By switching to a highly efficient. low carbon heating solution, such as a heat pump, you could be making a wise choice financially, and doing your bit to protect the future of our planet. 


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Your air conditioner (also known as a heat pump) is a highly efficient, low carbon way to heat and cool your home.

Heat pumps do use electricity, however, they are far more efficient than other heating systems because the amount of heat they produce is more than the amount of electricity they use. If you want to reduce your carbon footprint further, there are many energy suppliers to choose from who guarantee 100% green electricity from renewable sources.

Refrigerant is a vital component contained within your air conditioner. Once considered very detrimental, modern day refrigerants contained in AC systems are kinder to the planet. They have higher pressure and produce more heating power, which in turn reduces energy consumption.

The government has ambitious plans to reach net zero emissions by 2050, which means that heating systems powered by fossil fuels will become a thing of the past and all of our electricity will be coming from renewable sources.

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Installing a low carbon heat pump/air conditioner is a cost effective, sustainable heating and cooling solution, and the government are fully endorsing this by introducing a zero-rate of VAT for their installation.



All air conditioners contain refrigerant which has historically had bad press due to its contribution to the greenhouse effect. However, in an ever advancing world technologically, and following the introduction of F Gas Regulations, the AC industry has invested heavily into producing air conditioners which are more efficient, and have less environmental impact.

The introduction of R32 refrigerant gas, shows that that the AC industry really means business when it comes to protecting our planet. R32 has a global warming potential of two thirds less than other refrigerant gases, making it kinder to the atmosphere. It is now readily available, easy to reuse, recycle and install.


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The simple answer to this question is NO! However they do use electricity for power, and unless your electricity is coming from renewable source it will be being generated from the burning of fossil fuels e.g. coal, oil or natural gas, a process with releases CO2 and other green house gases into the atmosphere. You as a consumer can choose where your electricity comes from by switching to a Green Energy Supplier, and as we discussed earlier, the UK is legally bound to produce electricity from renewable sources only by 2050.


Annual service and maintenance checks by a qualified engineer are recommended and will improve your air conditioner’s efficiency and performance. This in turn will help to keep your running costs and bills low, reduce your energy usage and in turn reduce your environmental impact.


As mentioned before technology in this area has advanced at a rapid pace. Air conditioners have become more compact and aesthetically pleasing in design and contain environmentally conscious energy saving features.

Of course, with such a variety available, choosing the most eco-friendly air conditioner can seem a daunting task.

To help you with your search, look for units that contain R32 refrigerant, have A*** energy ratings, (this usually applies to smaller models), smart sensors and are WIFI enabled, allowing for maximum efficiency and total temperature control.  We have listed below some models that are a popular choice.

To make your decision an informed and easy one, we would advise you to contact a specialist AC installer, who will be able to assess your needs and recommend a suitable solution.

Mitsubishi Electric Air Conditioning Wall Mounted in Lobby 5

Mitsubishi MSZ-LN Mitsubishi MSZ-LN R32 Inverter Heat Pump

A*** energy rating (smaller models). Features i-save mode to reduce power consumption, 3D i-see sensor which switches the unit off when room is empty. R32 refrigerant. Built in WIFI interface.

Daikin Black Stylish

Daikin ‘Stylish’ range

A*** energy rating (smaller models), smart sensors, high efficiency, the ‘coanda’ effect, compact design. R32 refrigerant.

Etherea 2

Panasonic Etherea with nanoe™ X technology

A*** energy rating (smaller models). low energy cost and consumption. R32 refrigerant. Advanced control options, stylish design, and intelligent features.

fujitsu 2

Fujitsu Eco range

A** energy rating, Outstanding energy efficiency is achieved by using a high-efficiency lamda heat exchanger, large crossflow fan and R32 refrigerant. Smart device control (optional). Low ambient operation.

Evergreen provide AC services to suit all budgets and applications. For expert advice on installation, maintenance, or emergency repair of an AC system in your home please contact our specialist team.

0% VAT for Domestic Air Conditioning Systems

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Chancellor scraps the VAT on heat pumps…

Exciting news emerges for the AC industry as the 2022 Chancellor’s Spring Statement reveals that homeowners who have energy saving building solutions installed in their homes, such as heat pumps, no longer need to pay VAT.

The changes will take effect from April 2022 and will last five years, providing benefit to both homeowners and contractors in the industry.

If you’re looking for home air conditioning, 0% VAT means there has never been a better time.

Predicted increase in demand…

With the current hot topic of rising energy prices, and the government’s zero emissions goal for 2050, we predict that this will boost the market for energy saving, low carbon heat pumps that not only offer a viable, cost effective and sustainable heating solution during the winter months but can also provide welcome relief from the soaring summer temperatures.

With low running costs and high efficiency, the purchase of an AC system to heat and cool your home, is a decision that is easy on your pocket and on the planet, as we all have a part to play in helping to reach the UK’s climate goals.

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The rules on installation on energy saving materials…

The rules of qualifying installations have also been simplified considerably alongside the cuts. In the past, systems used to cool were not eligible for the reduced rate. Now, as long as the system can provide heating in addition to cooling to a domestic property, it is eligible for the scheme.

Prior to April 1st 2022, there was a ‘60% test’ in place which has also been abolished. The ‘60% test’ was implemented by HMRC. This would limit the reduced VAT rate where materials exceeded 60% of the total cost charged to the customer.

Resellers of air conditioning units without the installation service must continue to charge 20% VAT.

The scheme does not apply to portable systems and is set to run from April 2022 to March 2027.

You can read the full notice on the government website here.

Are air conditioning systems classed as heat pumps? …

Most air conditioning systems are considered as heat pumps due to the fact they can provide heating and cooling. Otherwise known as air-to-air heat pumps. Modern day gasses (R410a and more recently R22) have higher pressure and produce more heating power. Modern day technology means that air conditioning heating is now extremely efficient. Read more on how air conditioning works here.

What are ESMs?

ESMs is simply an abbreviation of Energy Saving Materials. Energy saving materials are products and/or systems that use as little electricity, gas, etc. as possible, or help to reduce their use. They lower the impact we have on our environment, which is why the government is providing incentives for us to install them. ESM’s come in different forms but they can be divided into groups as follows:

  • Controls for central heating and hot water systems
  • Draught stripping
  • Solar panels
  • Ground source heat pumps
  • Air source heat pumps

The government has recently introduced a zero rate for installation on the following ESMs…

  • Controls for central heating and hot water systems
  • Draught stripping
  • Insulation
  • Solar panels
  • Ground source heat pumps
  • Air source heat pumps
  • Micro combined heat and power units
  • Wood-fuelled boilers
  • Wind turbines
  • Water turbines

Why has 0% VAT for air conditioning installation been introduced?

The government has plans to drastically reduce domestic carbon emissions and this is all part of the wider net zero objective that we have already discussed. They have scrapped the previous complicated VAT rate scheme on certain specified energy saving materials, replaced it with a zero rate of VAT. 

 It is anticipated this money saving move will incentivise homeowners to take-up ESMs such as heat pumps (and this includes most air conditioners).

Can I get a grant to install air conditioning?

The government has introduced grants to encourage homeowners to install low carbon heating systems such as heat pumps, including most air conditioners, through the Boiler Upgrade Scheme (BUS). This scheme will “help property owners overcome the upfront cost of low carbon heating technologies”. This only applies to installations after April 2022.

To find out if your installation meets the criteria for a BUS grant there is more information on the GOV.UK website.

Where to go for AC advice ...

There are many different options to choose from, so it is important that you contact a specialist installer, who can advise you on which type and brand of air conditioner is best for your individual requirements and budget.

Evergreen provide AC services to suit all budgets and applications. For expert advice on installation, maintenance, or emergency repair of an AC system in your home please contact our specialist team.

Do I need planning permission for air conditioning?

One of the most common questions asked by consumers when considering air con for their home is if they need planning permission.

In this article we will walk you through the current legislation and regulations to ensure you are compliant when you have your air conditioner installed. 

What is planning permission?

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Simply put, applying for Planning Permission, is putting in a request to the authorities to see whether you can legally carry out building works, or alterations, to your property.

Once your application has been reviewed by your local planning authority It will be granted (perhaps subject to certain conditions) or refused.

It is essential that you do not carry out any works until you have secured planning permission, or have established that you do not need it, otherwise you could be served with an Enforcement Notice with is a legal order to undo any changes you have made to your property.

Do you need planning permission to install domestic air conditioning?

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In most instances, as long as you adhere to the permitted development regulations, it is not a requirement in domestic settings unless you are installing in one of the following areas …

If you have any doubt about your legal position with regards to installing an air conditioning system to your property we would advise you to contact your Local Planning Authority.

In most instances, as long as you adhere to the permitted development regulations, it is not a requirement in domestic settings unless you are installing in one of the following areas …

If you have any doubt about your legal position with regards to installing an air conditioning system to your property we would advise you to contact your Local Planning Authority.

What about air conditioning for Listed Buildings or in Conservation Areas?

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A Listed Building will need Listed Building Consent and a property within a Conservation Area will need planning permission before being able to the install an air conditioner. This is a legal requirement. 

There are often restrictions in place when it comes to alterations that are likely to affect the character or fabric of a Listed Building, or spoil the appearance of a Conservation Area, and this can mean in some cases that a traditional external condenser unit cannot be installed. 

It is worth bearing in mind that planning requests can take anywhere from 6-14 weeks (in some cases longer) to be processed, so be sure to get your application in during the colder months if you want your air conditioner to be up and running in the Summer. 

Your specialist installer would be happy to discuss different options with you so that your application is likely to be looked upon favourably by your local authority.

What are the air conditioning installation guidelines I should be aware of?

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There are some important regulations that need to be adhered to when you are deciding where to install your air conditioner. As we mentioned earlier, failure to comply with guidelines and regulations could lead to you being forced to undo any changes you have made to your property. 


Modern technology means that the noise created by external units are minimal. However, you should still be considerate towards neighbours and surroundings.

Legislation says that air conditioning units must not exceed 5 decibels above the ambient background noise level measured at any property boundary at peak hours. 

Complaints from neighbours and members of the public may result in your unit having to be removed. You may wish to consider some sound proofing such as fences and hedges to keep noise disturbance to a minimum. 

Space and boundaries

Always ensure your outdoor AC unit is installed more than a metre away from any property boundaries. It must not be positioned within metre of the edge of a flat roof. 


The volume of the external unit must not exceed 0.6m³

Roof installation

It is advised not install your outdoor unit on a pitched roof, otherwise you may have to consult your local council. 

Wind Turbines

No wind turbines to be located on the same building or within the curtilage of the building where the AC system is to be installed. (The curtilage of a building or house is the land immediately surrounding it, including closely associated buildings.)

What other air conditioning regulations do I need to be aware of?

If you’re having an air con system fitted in your home, it is very unlikely that you’ll need to file a planning application or worry about legislation (unless your property is listed or located in the restricted areas mentioned above). Your installer should be equipped with this knowledge and highlight anything you need to consider. 

Commercial buildings are separate when it comes to regulations, and there are certain requirements which must be adhered to, to ensure you are within government guidelines:

  • F-Gas 

Records must be kept by the building owners/occupiers and systems must be regularly maintained 

  • EPC 

By law, all commercial buildings that have over 500m2 if habitable space must hold an energy performance certificate 

  • TM44 

All commercial building owner/occupiers that have an AC system must undergo regular inspections by accredited professionals to ensure their system(s) are running efficiently. 

Where do I go for advice?

If you are still unsure whether you need to submit a planning application to install an AC system to your property it would be worth contacting your local authority for advice to ensure you are fully compliant. 

It is also worth enlisting the help of an AC contractor that is knowledgeable and experienced. Get in touch with our specialist team at Evergreen, we are on hand to offer free advice on any aspect of AC installation.

How Much Does an Air Conditioning Service Cost?

(Based on UK market averages)

The regular servicing of your air conditioning system will increase its efficiency and lifespan, reduce running costs, and help to keep your energy bills low.

There are several different types of installation, ranging from single split systems to complex VRF or VRV, and each have their individual service requirements. If you have searched this subject on the internet, you may well have been left very confused!

Here we discuss the different service costs attributed to each type of installation and attempt to answer the most asked frequently questions on air conditioning service and maintenance …

Domestic air conditioners service costs…

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These are commonly split or multi-split type systems.  Most air conditioning companies will charge the same for all varieties of units. As a rule of thumb, a domestic air conditioner should be serviced once a year and will cost anywhere between £70-£120 per indoor unit. There will usually be a reduction in the price per unit if you have multiple units being serviced during one visit. 

The cost will also depend on your location; you might pay more for a service in central London as opposed to other locations as the engineer will have to factor in the cost of travel and parking. If access equipment is required to reach the units, this is also likely to be chargeable. 

Commercial air conditioners call-out costs …

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These are commonly VRV or VRF type systems. You will typically pay a fixed call out fee which will normally include the first hour. Market averages indicate that you will pay somewhere between £130 – £180 during core working hours. Rates can vary anywhere between £170 – £220 for attendance out of normal working hours and on the weekend. 

Planned maintenance for commercial buildings costs …

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Most air conditioning contractors will offer planned maintenance contracts. This means your air conditioner service will be scheduled and rates agreed via a quote or signed contract in advance. Planned maintenance packages should be tailored to your specific requirements and reduce the risk of breakdowns occurring. Depending on individual requirements, you can expect to pay between £40 – £100 per unit for multiple units as part of a planned maintenance agreement. 

What is factored into the cost of my air conditioning service and maintenance?

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When requesting a quotation for air conditioning service it may be helpful to bear in mind that the following factors must be allowed for in the calculations:

  • Labour costs 
  • Travel costs
  • Refrigerant costs for re-gassing
  • Replacement parts
  • OFN (used to pressure test systems)
  • Reclaim Cylinders (used for reclaiming and disposing of refrigerant no longer required)

How much does it cost to repair an air conditioning unit?

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These are indicative figures. Fixed costs can be provided by your local air conditioning contractor subject to the cost of replacement parts and the labour required to carry out the repair.  

(Inclusive of parts and labour)

Indoor PCB between £300-£1000

Solenoid valves between £200-£800

Thermostat between £100-£250

Outdoor PCB between £300-£2000 dependant on the size of the system and manufacturer. 

Fan motor between £200-£500

Leaks between £300-£2000 The system may require a repair, re-gas and pressure test. Dependant on where the leak is and the size of the system. You need new reirrigation gas and to pressure test, bigger systems need more. 

Compressor between £1000-5000 For commercial building systems, this will usually include replacement of all the existing refrigerant gas, a local pressure test and usually would require master PCB board to be changed. For domestic systems you may be looking at between £1-2k, in this case it may be more cost effective to replace the system

Air conditioning servicing and maintenance FAQ’s …

Here we answer some of the most frequently asked questions, however if you have any additional questions or concerns your expert AC installer should be happy to help you.

How often should I have my air conditioner serviced?

Domestic: at least once annually  

Commercial: at least twice, annually 

F-Gas legislation states that if a building has over 500 tonnes of gas, then you must have a professional service carried out at least four times a year. For anything under that, most contractors would recommend a routine service at least twice a year. 

How do I clean my air conditioner?

You may be able to carry out a basic clean yourself and can follow these steps However, we would recommend a thorough service by a qualified AC engineer to prevent any future costly defects. 

How can I reduce energy consumption?

Make sure your systems are regularly maintained and ensure windows are closed whilst your systems are running. 

What does an air conditioning service include?

Thorough clean of the systems components such as the filters, coil, fan and drain pan. 

Can I service my air conditioner myself?

You may be able to give your air conditioner a basic service inclusive of cleaning fans and filters. However, you should enlist an expert for to ensure a thorough service at least once a year, an expert will be able to pick up on minor issues and prevent them from worsening. 

Should I repair or replace my air conditioner?

Dependant on how well a system has been maintained and how much it has been used; you should look to replace it around the 10-year mark. If you book a survey with a qualified engineer, they will be able to advise whether the system needs replacing or not.

How do I know if my air conditioner needs to be serviced?

You may experience odours from your air conditioner that indicate it needs a service. You may experience insufficient airflow, leaks noises or humidity. All are tell-tale signs that you need a professional to get it back to working order again.

How long should my air conditioner last?

This depends on the following

  • How well a system has been installed
  • How well a system has been maintained
  • The location of units (e.g., is the outdoor exposed to harsher elements for example by the coast and subject to salt erosion). 
  • How often the units have been in use

A well looked after air conditioning system can last anywhere from 10 – 15 years if it has been properly maintained and cared for. 

What does a commercial planned maintenance visit include?

The types of things a commercial maintenance visit will includes are as follows: 

  • Hoovering out of fan coil units internally and externally.
  • Chemical clean of all indoor unit coils using anti-bacterial coil cleaner which kills Covid 19
  • Washing of fan coil unit casing.
  • Cleaning of indoor fan coil unit filters.
  • Qualified visual inspection of internal components for indoor and outdoor units.
  • Tightening of accessible electrical connections.
  • System functional checks.
  • Brushing out of outdoor unit condensers clear from dirt and debris.
  • F Gas checks.
  • Updating of F Gas records.
  • Full System Reporting.
  • Hoovering off surface dust on the ceiling mounted supply and extract grills.

Evergreen Air Conditioning have a dedicated in-house service and maintenance team. We offer emergency call outs, domestic and commercial servicing, and planned maintenance. Call 08081781678 or email for free quotations and advice. 

What is the Best Air Conditioner Temperature for Sleeping?

In this article we discuss how room temperature in the bedroom is an important consideration and how your air conditioner can play a key role in helping you sleep well.

Why is a good night’s sleep important?

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Most people welcome their comfortable bed after a long day. But apart from the delicious feeling of waking up fully rejuvenated after a restful night, did you know that sleep is vital for survival and health?

We should never underestimate the importance of sleeping well, it is essential to your overall wellbeing, it protects you physically and mentally, as well as boosting your quality of life and improving your performance.

Sleep deprivation is linked to a large range of health conditions including diabetes, depression, obesity, heart attacks and cancer. Lack of sleep suppresses your immune system which leaves you vulnerable to infections and metabolic and hormone changes.

Research suggests that “four in ten people aren’t getting enough sleep, while one in five sleep poorly most nights, representing the second most common health complaint after pain.”

How can we sleep better?

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Although sleep is a natural process that our body does involuntarily, our busy lifestyles, and bad habits, often prevent us from getting the good nights sleep that we need. Poor sleep hygiene leads to poor quality sleep, so it is important to create the perfect environment to promote a restful night.

There is a wealth of information available about this subject, in fact hours spent reading the research on this could actually send you to sleep!!! Try cutting out stimulants such as coffee after midday, reducing alcohol consumption and turning off your mobile phone half an hour before you climb under the sheets….. these are simple steps you can take to help you drop off quickly. Excess heat, light and noise can also prevent us from falling asleep and could also be the reason we wake during the night too.

Can an Air Conditioner Help Sleep?

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An air conditioner will regulate your bedroom temperature and is a godsend on a sultry summer’s night, but did you know there are other benefits that an air conditioner can provide to help you get off to, and stay, asleep.

Air Conditioners Reduce Humidity

A humid, damp environment can be very detrimental to our health. In fact, enclosed areas where humidity is high, can cause wakefulness and prevent us from sleeping deeply but more concerning is that high humidity is strongly linked to an increase in mould, dust mites, dehydration and heatstroke all of which are harmful to health.

Air Conditioners Reduce Allergens

Air conditioners contain air filtration systems that can reduce dust mites, allergens and pollutants, which can lead to, or exacerbate, respiratory illness.

Air Conditioners Improve Air Quality

Air conditioners can help us to breathe easier, by assisting in the removal of dust and bacteria from the environment.

Air Conditioners Reduce the Risk of Dehydration

Keeping the air at the optimum temperature reduces the amount of water we lose from our body through sweating. When temperatures in the summer months soar, dehydration can be an unpleasant side effect causing headaches, dry mouth and nose, snoring and cramps all of which can be very disruptive and uncomfortable.

Air Conditioners Keep Unwanted Pests at Bay

An invasion of unwanted flying or crawling pests into your bedroom could be very frustrating when you are trying to rest. No one wants to be bitten in their sleep or worst still wants to be chasing an annoying insect around their room in the middle of the night. The installation of an air conditioning system will put a stop to any unwanted visitors of this kind, by being able to maintain a comfortable temperature with windows and doors closed.

Air Conditioners Eliminate Odours and Fumes

If you live in an area that is highly polluted because of traffic volumes, or industrial buildings you can keep your windows and doors shut, whilst still maintaining a comfortable room temperature The air filtration system in your air conditioner can enable you to breathe easier and help to provide cleaner air that is free from odours and fumes.

Air Conditioners Reduce Noise

If your bedroom faces a busy road or you live in a built up area it can be difficult to fall asleep, and stay asleep. The luxury of being able to keep windows and doors firmly closed especially during the hotter months, means that any distraction from outside noise is kept to the minimum.

Is it Better to Sleep in Cooler Temperatures?

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During a 24 hour period your body’s internal temperature fluctuates, this fluctuation is all part a natural cycle that we refer to as our body clock. In technical terms this is called your circadian rhythm which regulates your biological and physiological processes. From late afternoon your body decreases in temperature in preparation for the nocturnal sleep phase. With this in mind it makes good sense to be mindful of your bedroom temperature, keeping the temperature cooler rather than hotter.

What is the Perfect Air Conditioner Temperature for Sleeping?

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Most people will agree that a comfortable bedroom temperature is key to achieving a good quality night’s sleep in fact a National Sleep Foundation Poll concluded that “two-thirds or more rated the following elements as important in getting a good night’s sleep: Cool room temperature (79%) Fresh air, free of allergens (75%)”.

Adjusting or programming your air conditioner to maintain the best room temperature to sleep in is key to improving your sleep quality, of course this varies from person to person, but it is recommended that you set your thermostat somewhere between 20 and 24°C. In the industry any temperature within this range is classed as comfort cooling, which of course is self explanatory. There will be other variables that affect your decision though, for example, you may prefer thicker bedding or nightwear and a lower temperature or vice versa.

What is sleep mode in my air conditioner?

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If you air conditioner comes equipped with this function, your room temperature will automatically be regulated to keep you comfortable through the different stages of sleep, decreasing or increasing room temperature in line with your body’s natural sleep cycle.

This also ensures that your AC system is working economically, so you can rest assured that you are helping to keep your energy bills low.

Evergreen Air Conditioning Limited provide air conditioning services to suit all budgets and applications. For expert advice on installation, maintenance, or emergency repair of an AC system in your home or workplace, please contact our specialist team.

Who Invented the AC Unit?

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Air conditioning, once considered a luxury afforded only by the wealthy, has in modern times become more commonplace, and indeed part of everyday life.

In countries where extreme heat, humidity or pollution pose a threat to life, it is considered a necessity.

Here in the UK, we have recently seen soaring summer temperatures resulting in a dramatic increase in demand. During the pandemic, the government requested that where possible we should work from home, further highlighting the need for domestic AC.

With scientific and technological advancements (and the brain power of some very clever individuals), we are now able to control surrounding temperature at the touch of a button and air conditioning has become accessible to all.

It is clear that the invention of the modern-day air conditioner is not as the result of a single invention, but the result a series of exciting discoveries along the way, here we take a closer look into its history and attempt to answer some of the most asked questions about this important discovery…….

Why was air conditioning invented and when?

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Delving back into history we can see that evaporative cooling techniques have been used for many years. Evaporative cooling is the conversion of liquid water into vapour using the thermal energy in the air.

It is well documented that centuries ago the Ancient Egyptians used this method to reduce the temperature inside their buildings. Sodden cloths or reeds were hung in doorways and windows, and as the warm air passed through them the liquid would evaporate. This process reduced the temperature of the surrounding air.

Clay pots (qullah) filled with water were also strategically placed in rooms. The intense heat would cause the water to evaporate and produce a cooling effect. If you were lucky enough to be rich, you could employ a slave to waft the cool air in your direction!

Other examples of where evaporative cooling techniques have been utilised thoughout history, and indeed are still being used today are mashrabiya (specially designed lattice windows) and windcatchers (a chimney like structure).

This is a very simple, cheap, and relatively effective technique, but is very dependent on climate conditions and location. Although evaporative cooling systems differ from modern day AC systems it was from here we could perhaps consider the concept of the air conditioner was born.

Who invented air conditioning as we know it today?

Over the years there had been many attempts to find other viable solutions to cool and control temperature. The need for cooling was not a problem that was just going to go away and there was increasing demand for temperature control on a larger more efficient scale.

Of course, there were many contributors to the development of air conditioning, for example we have discussed how the Egyptians utilised evaporative cooling, however it appears that the USA led the way in modern cooling techniques and four individuals in particular seemed to be held in high esteem, when it came to solving the problem of heat.

John Gorrie

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In 1842 Dr John Gorrie was a resident physician at two hospitals in Florida. Specialising in the care and treatment of tropical diseases, his research led him to believe that temperature paid a key role in the treatment and prevention of certain diseases. 

He devised a crude system to keep the hospital cool. By suspending basins from the ceilings filled with blocks of ice he was able to cool the sick rooms, helping to reduce fever. This was a simple enough solution, but it caused a big problem, as in order to maintain cool temperatures in the hospitals, the ice needed to be shipped in large quantities from a long distance away.

So convinced of his hypothesis that cool temperatures were key to disease control and prevention, John Gorrie decided to give up his medical career to concentrate on inventing other artificial cooling techniques.

This he did to a degree of success as in 1851 he was granted patent for the invention of a new and useful Machine for the Artificial Production of Ice and General Refrigeratory Purpose.

Unfortunately following the death of his financial partner Gorrie failed to get his invention off the ground and he sadly died alone and penniless.

Although Gorrie was not widely hailed as ‘the’ inventor of the air conditioner, without a doubt his invention played a key part in its development.

Willis Carrier

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In 1901 a bright young engineer, Willis Carrier, graduated from Cornell University with a Master of Engineering degree.

He quickly secured a position at the Buffalo Forge Company, and the following year was given the task of solving a humidity problem for a publishing company which was causing poor print quality of their magazines.

Carrier conducted various experiments and eventually came up with an innovative system to control the humidity. His invention the “Apparatus for Treating Air” was the birth of modern-day AC, and a patent was secured.

Realising its potential to be something ‘big’ Carrier continued to experiment and refine his invention and soon devised and patented an automatic control system for regulating humidity and temperature that could benefit many industries.

He eventually broke off from Buffalo Forge, forming the phenomenally successful Carrier Engineering Corporation with six other engineers.

Despite these exciting advancements in design and efficiency these AC systems were huge, bulky pieces of equipment and not very practical, especially for domestic use, so it was back to the drawing board once again….

HH Schultz and JQ Sherman 

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In 1931, H.H. Schultz and J.Q. Sherman developed and patented an air conditioner designed to sit on a window ledge. Unfortunately, the units were very expensive, and during a time of economic and political crisis, it was a luxury out of reach for most.

However, Schultz and Sherman’s innovative invention set a precedent for future window air conditioners. New patents soon sprang up for smaller, compact and less inexpensive versions.

During the 1950’s post war economic boom domestic AC units became very desirable. In the years that followed their popularity exploded, it is reported that across the United States of America over a million units were sold in 1953.

Compared to the USA, the UK’s demand for domestic cooling has had a slow start. However, with recent spikes in summer temperatures, a growing “working from home” culture and the latest trends in building design, there has been considerable growth in this market.

What about the future of AC?

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This article would simply be too long if we touched on every invention and development throughout the history of the air conditioner, so here we have mentioned some of the ‘key players’ whose innovative ideas have contributed to the air conditioner as we know it today.

Since its humble beginnings there have been many advancements in the design and technology of the air conditioner.

From single mini split systems to highly complex VRF systems, efficient and affordable heating and cooling can now be enjoyed at the touch of a button in a variety of domestic and commercial settings.

However, the story does not end there…..

Demand is on the increase, and the customer is ever changing in its requirements. Whether the hot topic is environmental impact, energy efficiency, aesthetics or smart technology ….. the industry continues to evolve and adapt to deliver solutions.

Evergreen Air Conditioning Limited provide AC services to suit all budgets and applications. For expert advice on installation, maintenance, or emergency repair of an AC system in your home or workplace, please contact our specialist team. 

Evergreen expand to Hertford!

We are very excited to announce that, following the continued success and growth of Evergreen, we have recently acquired new premises, in Cole Green, Hertford (Hertfordshire).

For many years we have been operating out of our Wickford office providing air conditioning installation, and related services, to Essex and beyond, and opening a second office is something we have been discussing for some time.


It has been a busy few weeks, purchasing and assembling the furniture and making sure that we have everything we need in one place.

It has quite literally been all hands-on deck, even Maggie the office canine, and head of security, has been shifting cardboard boxes back and forth (and tearing up a fair amount of them too!)

Our new office is a beautiful, listed building, which has been carefully renovated to keep its existing features whilst a providing bright, spacious, and welcoming place to run our business from.

Time for a break and some well-earned refreshment!

Ideally located in a rural setting just outside of Hertford, we are now perfectly positioned to offer our air conditioning services throughout Hertfordshire, with the added bonus of a beautiful setting with plenty of car parking for visitors and staff alike.

If you are based in Herts and are interested in having domestic or commercial air conditioning installed, or you need to book a service or maintenance visit, please drop us a line.

Or if you happen to be passing, do call in for a cup of coffee at our Hertford office, we would love to show you around!




An air conditioner is a highly complex appliance and the installation process involves careful and meticulous planning so that your home or business has sufficient heating and cooling functionality for your individual needs. This is why it is of upmost importance to choose the right air conditioning installer who has the experience, qualifications and expertise to guide you through the process.

Follow our simple step by step guide, to help you choose the right air conditioning installer for you ……


When looking for an air con installer it is imperative that you choose a company that has the relevant experience and expertise, excellent client satisfaction, and also are up to date with the current trends and ever changing regulations.

As a bench mark we would recommend that you search for air conditioner installers that are well established, ideally for more than 5 years (this is a very competitive industry and over 80% of businesses will fail to reach this landmark).

Evergreen Environmental were established in 2010, and our board of directors have over 72 years of combined experience in air conditioning installations and related services. We employ a dedicated team of highly qualified and experienced specialist engineers.


You must ensure that your chosen air conditioning installer is fully compliant and up to date with industry & governmental standards, and that they have sufficient liability insurance for your protection.

Evergreen Environmental the air conditioning professionals in Essexare SafeContractor approved. We are F-Gas registered and are partnered and accredited with the leading manufacturers Mitsubishi Electric and Daikin, as well as other well respected manufacturers in the field. All of our highly trained engineers are Gas Safe registered and fully certified.


In the same way that an employer asks for references to employ a new recruit, you can hire an air conditioning professional using the same method. Start by collecting suggestions from your friends and family for the best HVAC Company in your area. Check out online reviews and directories listing businesses.

Evergreen Environmental are proud to have successfully been delivering projects to the highest of standards since 2010. Installations can range from a single wall mounted air conditioning unit, to multiple VRF in multi-storey buildings. Projects are carried out in a variety of domestic and commercial settings. We value each and every one of our Clients and we take great satisfaction in the fact that our Clients do not hesitate to recommend us, and a large proportion of our installations are repeat business.


You may have in mind a rough budget for what you require but whilst it is always tempting to save money and go with the lowest price, it is important to have a complete understanding of what you are getting for your money. Ask for estimates from various companies and compare each bid. Only consider estimates from companies that are the most suitably qualified and experienced for the work. Eventually, this will save you time and money.

Evergreen offer free site surveys, advice and quotations to all clients. During the air conditioning site survey, the installer will carefully consider your individual needs and tailor your installation to this. Our expertise enables us to compose the best air conditioning solution for each client.


Several companies offer air conditioning services, and nearly all claim to be the best. By following the simple points above and taking time to do your research, you will ultimately save time and money, and hopefully feel more confident in your final choice.

Evergreen Environmental are specialist air conditioning installers based in Essex, covering London, Essex and The Home Counties. We are an established and growing company. We take pride in our excellent reputation within the industry for the quality of our installations and level of service.

Our experienced team would be happy to assist you, so please contact us today on 08081 781 678 for your free quotation.

Alternatively you can email us at or complete the online form to receive a response within 24 hours.