Whether at home or work, everyone should feel comfortable in their environment. We all spend plenty of time at both Whether at home or work, everyone should feel comfortable in their environment. We all spend plenty of time at both locations, and with the summer months ahead, everyone will benefit from a temperature-controlled, humidity-free space.
When it comes to air conditioning systems, however, you may feel overwhelmed as you discover all the different options available to you. Which air conditioning system is suitable for a domestic setting, and what do you need to consider for a commercial property? Fortunately, we have put together this guide to help you establish the right air conditioning unit for your needs.
What this guide will cover:
- How to Choose the Right Air Conditioner: Your 5-Step Selection Criteria
- Choosing the Best Air Conditioner for Your Space
- Portable Vs Fixed Air Conditioning: What’s Better?
- Domestic and Commercial Air Conditioners
- BTUs: Determining What Size Air Conditioner You Need
- Cost Considerations
- Your Energy Efficiency Guide
- Installation Requirements
- Need Help Sourcing Air Conditioners
- FAQ
How to Choose the Right Air Conditioner: Your 5-Step Selection Criteria
Choosing the right air conditioner goes beyond just picking a type; it’s about matching your unit to your space, budget, and climate needs.
Here are the key factors to consider:
1. Room Size
The size of the space you want to cool or heat is the first consideration. Air conditioners are rated in BTUs (British Thermal Units), which measure cooling power. For most UK homes, a general guideline is 20-25 BTU per square foot.
- Too small a unit will struggle to cool or heat the room effectively.
- Too large a unit will cycle on and off frequently, wasting energy and reducing comfort.
2. Energy Efficiency
Energy-efficient units save you money in the long run and reduce environmental impact. Look for:
- A++ or higher energy ratings for optimal efficiency.
- Inverter technology, which adjusts the compressor speed to maintain a consistent temperature, rather than cycling on and off.
3. Installation Requirements
Consider whether your unit requires professional installation or can be a DIY project:
- Split, Multi-Split, and Central Air systems usually require certified installers due to refrigerant handling and ductwork.
- Portable and Window Units are generally easy to install yourself with minimal tools.
4. Running Costs
Your air conditioner’s upfront price isn’t the only cost; you should also consider annual electricity consumption.
- Energy-efficient models cost less to run over time.
- Calculate estimated annual running costs based on your unit’s energy rating and average usage hours to avoid surprises.
5. Climate Control Needs
Finally, decide whether you need:
- Cooling only (summer-focused units like portable or window ACs).
- Heating and cooling (split, multi-split, or central systems) for year-round comfort, especially in cooler climates.
Let’s delve into more detail to help you narrow down your search.
Choosing the Best Air Conditioner for Your Space
Depending on what area you are looking to cool or heat will determine which air conditioner you require. Some air conditioning systems will best suit certain areas or property uses. As an air conditioning system is a worthwhile purchase, becoming a huge part of your home and comfort, it is only right that you do your homework before making the necessary arrangements with a professional company.
There are three dominant types of air conditioning systems to choose from.
There are several key types of air conditioning systems to choose from, each with its own advantages depending on your needs and property type.
Split Air Conditioning Systems
The most common type of air conditioning system is the Split Air System. With this setup up there are units both inside and outside the room. The internal air conditioning unit is mounted on the wall, and the external unit is linked to this. A Split System does not require any great structural work; instead, an external wall is recommended so a small hole can be created to connect the two units.
This conditioning system is particularly efficient, allowing you to control the room’s temperature, even when you need to heat the room. Wall-mounted systems allow for floor space to remain intact, keeping the unit up high and out of the way.
Not only do these systems have impressive energy efficiency, but they are also easy to install and offer both cooling and heating benefits.
Multi-Split Systems
A Multi-Split System works much like a standard Split System but allows multiple indoor units to connect to one outdoor unit. This makes it an excellent choice for properties with several rooms or zones that require individual climate control without needing separate outdoor compressors. Multi-Split Systems are energy-efficient and flexible, but installation is more complex compared to a single Split System.
Central Air Conditioning
A Central Air Conditioning System is more common in new builds or homes undergoing more extensive internal works. This is due to the system requiring a more rigorous installation process. For older homes looking to set up a Central System, you would have to be prepared to cut into existing walls to implement the duct installation system. While the energy efficiency rating is desirable, the work that is involved in the installation will require a lot of upfront costs and time. An outdoor compressor will also be required, too.
We would only recommend this system for a property that is facing a remodel or excessive renovation, as it is an energy-efficient, effective and quieter option. However, if you have a smaller budget, it may be worth exploring other options.
Portable Air Conditioners
If you are looking for a quick-fix air conditioning system, then a Portable Air Conditioner may suit your needs. During hot summer months, these portable units are able to create a cooler environment in smaller rooms and areas, while their portable nature offers the flexibility to move the device wherever it is required.
Portable units are self-contained and generally require only a power outlet and a window or vent for hot air exhaust, making them easy to set up. However, they are less efficient than permanent systems and best suited for temporary or supplemental cooling.
Quick Comparison of Air Conditioner Types
| Air Conditioner Type | Best For | Installation Difficulty | Energy Efficiency | Portability | Notes |
| Split System | Single rooms or zones | Low | High | No | Wall-mounted, offers heating & cooling, minimal structural work |
| Multi-Split System | Multiple rooms/zones | Medium | High | No | One outdoor unit supports several indoor units, with flexible temperature control |
| Central Air | Whole-house | High | High | No | Requires ductwork and remodel, quiet and energy-efficient |
| Portable Unit | Temporary or small rooms | Low | Medium | Yes | Self-contained, easy to move, less efficient than permanent systems |
Portable Vs Fixed Air Conditioning: What’s Better?
When deciding on which option best suits your needs, the first decision you need to make is whether to install a fixed air conditioning unit or make do with a portable unit. Whilst they create a refreshing environment, Portable Air Conditioners are only able to cool a room. They are unable to offer heating and cooling settings, unlike the Split Air and Central System. It is also worth remembering that the large majority of portable air conditioner designs require the need of a nearby window, allowing the unit’s hose to send water vapour outside.
Portable Air Conditioners may not blend into your home or work environment, but if you are in rented accommodation, your AC unit can simply come with you. Their movable designs come complete with wheels to add to their ease of transportation. However, this comes at the cost of disruption; these units can be quite noisy and, consequently, more disruptive than a fixed system.
When considering Portable Air Conditioners, it is best to approach them from a cost perspective. This option offers a cheaper alternative than permanent installations in the short term. Over a long period of usage, these systems are much less efficient. But their instantaneous setup will offer you relief from exceptionally hot days in a much shorter turnaround.
Nowadays, you also have the option to add Wi-Fi controls to your air conditioning system, making them incredibly easy to use. The only design that does not come with this added extra is portable units. Unlike fixed systems, Portable Air Conditioners are extremely simple in their functionality. If you are looking for an air conditioning system that has a wider range of options that are carried out discreetly in your environment, then it is worth exploring the installation options of fixed systems.
Domestic and Commercial Air Conditioners
Whether you are looking for air conditioning systems for a home or work setting, there are certain characteristics you may need.
For domestic homes, as well as opting for energy-efficient units that won’t cost the earth to run, it is also important to consider the noise. Opting for quieter units will allow your family to enjoy the cool environment without being kept up at night or disrupted throughout the day. We would also recommend exploring discrete installation options; you don’t want your AC unit to be the first thing you or guests notice.
Moreover, in the home, particular rooms may require specific requirements. For example, loft conversions often struggle to have a regulated temperature. Being up within the rafters, these spaces suffer from being overly hot in the summer months, but cold in the winter. Similarly, conservatories and home gyms are susceptible to variations in temperature. Fortunately, air conditioning units are now able to adapt to work in most spaces, helping to keep your family comfortable, no matter how the space is used.
On the other hand, commercial spaces require air conditioning and ventilation systems for different purposes. With the need now for top-quality filters and humidity control, a professional air conditioning system can help to reduce indoor air pollution for your staff. The most important factor for businesses is to calculate the size of the air conditioning unit you require.
Whether you are installing air conditioning in a domestic or commercial environment, there are many different designs to choose from. And, additionally, there are a range of installation methods to explore, including:
- Floor-Mounted
- Wall-Mounted Split Systems
- Ceiling Mounted
- Ceiling Suspended Units
- Portable Units
It is best to gain an industry expert’s knowledge on all the available options, as there are lots of makes and models available for each.
BTUs: Determining What Size Air Conditioner You Need
When you are considering implementing air conditioning, the unit’s BTU rating is crucial. The British Thermal Unit (BTU) is the figure that lets you know the potential power of an air conditioning unit. It refers to the amount of energy the unit requires to heat a pound of water by one degree Fahrenheit.
You may be familiar with a BTU rating with a heater, but this reading is also relevant to your air conditioning device. These units work by removing the heat from the air and pumping this cooler air back into the room. The BTU value can be understood in the same way it would for a heating unit; the only difference is that the figure refers to the amount of heat it can remove. Therefore, the higher the BTU rating, the more powerful the air conditioning system.
How Many BTUs Does Your Home Require?
Despite a high BTU rating equating to a more effective air conditioning system, that does not mean your room will require the most powerful air conditioning unit on the market. Instead, it is important to select the appropriate unit for the size of the room you wish to cool.
Certain factors that affect your requirements are the size of your home and its square footage. However, the height of your ceilings will also play a part, as this will influence the cubic area that will need cooling. In most cases, homes have 8-foot high ceilings, and most approximations work off these assumptions.
For a quotation, we would recommend the following BTU ratings in relation to the square footage of your home:
| Room Size (sq. ft.) | British Thermal Unit (BTU) |
| 100 to 150 | 5,000 |
| 150 to 250 | 6,000 |
| 250 to 300 | 7,000 |
| 300 to 350 | 8,000 |
| 350 to 400 | 9,000 |
| 400 to 450 | 10,000 |
| 450 to 550 | 12,000 |
| 550 to 700 | 14,000 |
| 700 to 1,000 | 18,000 |
| 1,000 to 1,200 | 21,000 |
| 1,200 to 1,400 | 23,000 |
| 1,400 to 1,500 | 24,000 |
| 1,500 to 2,000 | 30,000 |
| 2,000 to 2,500 | 34,000 |
There are other considerations that must be touched upon. Before installing an air conditioning system, a company should account for your property’s floor plan and how many individual units are needed. Open plan living will require a higher BTU rating than homes with enclosed rooms. Equally, a sprawling floor plan will also need more BTUs.
The location of your house will also play a part in which air conditioning system is best for you. Homes located in hotter climes will require devices that can work harder to keep your house cool. This concern is often a consideration for properties abroad. However, factors closer to home include standards of insulation and the number of windows. Well-insulated homes are able to retain their internal temperature better. Although window standards have improved greatly over the years, windows won’t provide the same level of insulation as cavity wall insulation, for example. Therefore, this provides another factor to consider.
How Many BTUs Does a Commercial Building Need?
For a business, your air conditioning system’s performance requirements will vary depending on additional factors. In addition to the location and dimensions of your commercial premises, you will also need to make allowance for:
- The number of people using the space
- How many tea and coffee machines are there
- The total amount of electrical equipment
To make it easier for you to estimate your options, you can explore our Air Conditioning Calculator. Once you have filled in the necessary information, you will receive an estimated cost for your premises installation.
Why is the amount of BTUs Important?
Establishing the correct amount of BTUs for your space is incredibly important. While it may seem that a more powerful device would be a win-win for you, surely your room will cool quickly, providing you with instantaneous relief. However, the reality is quite different. Cooling your room too quickly can have a negative impact on your room’s moisture levels.
When an air conditioning unit reduces the temperature of a room, it also removes moisture. Cooling a room at a faster rate results in the device turning off before it has had time to remove the moisture from the air. Another negative is that the device would have to work harder to maintain the colder temperature. This means the air conditioning system would be kicking in more frequently, leading to wear and tear earlier in its lifecycle and heightened running costs.
Similarly, installing a device that does not have enough BTUs has its problems. If the system is much too small for the space, it will have to run at maximum power to keep the room cool. This results in the unit drying the air out too much. Furthermore, running at maximum power consistently will see your power usage increase, while the unit will wear out prematurely.
Cost Considerations
When considering an air conditioner for your home, understanding the costs in the UK can help you budget effectively.
Approximate Air Conditioner Costs:
- Portable Units: £200-£800
- Wall-Mounted Split Systems (unit only): £500-£2,500
- Installation Costs (split systems): £300-£1,500
- Multi-Split Systems: £1,500-£5,000+
- Running Costs: £50-£300 annually, depending on usage
These figures show that while portable units are affordable and convenient, permanent systems like split or multi-split units involve higher upfront costs but can offer better energy efficiency and year-round climate control.
Your Energy Efficiency Guide
Energy efficiency is a critical factor for both environmental impact and running costs.
Look for the following indicators when choosing an air conditioner:
- A+++ Rating: Most efficient, lowest running costs
- A++ Rating: High efficiency, moderate running costs
- A+ Rating: Good efficiency, standard running costs
- Inverter Technology: Adjusts compressor speed, 30-50% more efficient than fixed-speed units
- SCOP Ratings: Seasonal performance rating for heat pumps, showing heating efficiency over time
Choosing a highly efficient unit can significantly reduce your electricity bills while keeping your home comfortable.
Installation Requirements
Proper installation is not just about performance; it’s a legal requirement in the UK. Here’s what you need to know:
- F-Gas Certification: Required for installation of split and multi-split systems containing refrigerants
- Building Regulations: External units must comply with local planning rules
- Planning Permission: Necessary for Listed buildings or properties in conservation areas
- Electrical Safety Compliance (Part P): Ensures the installation meets UK electrical safety standards
- Noise Regulations: Residential units must comply with local limits on outdoor noise
Professional installation ensures legal compliance, optimal system performance, and long-term reliability.
Need Help Sourcing Air Conditioners
Once you have your domestic or commercial air conditioning system set up, we can further support you with the cleaning and maintenance of your air conditioning unit. Most people are unaware, but it is recommended to have your air conditioner serviced at least twice per calendar year. With our help, you can ensure your system is safe and functioning at its maximum capacity.
If you have any questions regarding which air conditioner is right for you, or would like more information on the recommendations you now have, our experts are happy to advise.
There is no room for complacency at PRA Air Conditioning – give us a call today.
FAQ
What type of air conditioner is best for UK homes?
Split-system air conditioners are usually the best choice for UK properties. They offer excellent energy efficiency, quiet operation, and the benefit of both cooling and heating year-round. For renters or those needing a temporary solution, portable units are a flexible option that doesn’t require permanent installation.
How do I work out what size air conditioner I need?
A simple rule of thumb is to measure your room in square feet and multiply by 25 BTU. For instance, a 200 sq ft room would need around 5,000 BTU. You should also consider factors such as ceiling height, insulation, and how much direct sunlight the room gets, as these can increase the cooling demand.
Do I need planning permission to install air conditioning in the UK?
In most cases, air conditioning installation is covered by permitted development rights, so you won’t need planning permission. Exceptions apply for listed buildings, flats, or homes in Conservation Areas, where approval may be required. Outdoor units must also comply with local noise regulations.
What’s the difference between portable and split air conditioners?
- Split Systems: Consist of an indoor and outdoor unit, offering superior efficiency, quieter performance, and heating capability, but they do require professional installation.
- Portable Units: Self-contained, easy to move, and don’t need specialist installation, but they tend to be noisier and less efficient.
How much does it cost to run air conditioning in the UK?
Running costs typically range from £50-£300 per year, depending on the unit’s efficiency, how often it’s used, and electricity rates. As a guide, a 9,000 BTU split system might cost around £0.50-£1.50 per day during the summer.
Can air conditioners also heat UK homes?
Yes, many modern systems function as heat pumps, providing both cooling in summer and heating in winter. They’re highly efficient in UK climates, often delivering 3-4 times more heat energy than the electricity they consume, making them a cost-effective year-round solution.
What maintenance does an air conditioner require?
- Clean or replace filters monthly during heavy use.
- Have the system serviced annually by a professional.
- Keep the outdoor unit clear of leaves, dust, and debris.
Note: Split systems require servicing by an F-Gas certified engineer if refrigerant handling is involved.
Can I install an air conditioner myself?
- Portable Units: Yes, these are designed for DIY setup.
Split Systems: No, these legally require an F-Gas certified installer due to refrigerant regulations. Attempting a DIY installation not only breaks the law but also voids the warranty.