With rising summer temperatures and a growing demand for indoor comfort, air conditioning is no longer just a luxury in the UK. It has become a practical investment for both residential and commercial spaces, particularly in cities like Bristol, where temperature fluctuations are becoming more frequent. But with so many models, features, and installation types available, selecting the right air conditioner can feel overwhelming.
At Controlled Climate, we’ve spent over 25 years helping homeowners and businesses across the South West make the right choices. This guide walks you through the ten key factors to consider when choosing the best air conditioning unit for your needs.
1. Start with a Realistic Budget
Your budget is the foundation of your air conditioning decision. Prices vary widely based on the system type, installation complexity, features, and capacity. While it may be tempting to opt for the cheapest option, it’s essential to consider long-term efficiency and potential energy savings.
For example, a basic portable unit may cost less upfront but could result in higher energy bills and limited performance. On the other hand, an energy-efficient wall-mounted split system may require a higher initial investment but provide better comfort and lower operating costs over time. Installation costs also vary depending on whether internal pipework, external access, or electrical upgrades are needed.
Budgeting should also account for annual servicing and potential upgrades like smart controls or zoning systems. Our Bristol-based air conditioning team is happy to provide tailored recommendations based on your property, goals, and budget, so you can make an informed investment.
2. Choose the Right Type of Air Conditioning Unit
Understanding the main types of AC units is essential when deciding what’s right for your home or office:
- Split Systems – These are among the most common for domestic and small commercial use. They consist of an indoor unit and an outdoor condenser. They’re energy-efficient, discreet, and capable of cooling multiple rooms when combined with multi-split setups.
- Portable Units – Ideal for renters or short-term cooling, these plug-in models can be moved from room to room. However, they tend to be noisier and less energy-efficient, and they require a window or door vent for hot air.
- Ducted Systems – Perfect for large homes or commercial buildings, ducted systems deliver even cooling through concealed ducts. They offer clean aesthetics and whole-building control but come with higher installation costs.
- Window or Wall Units – Often found in flats or offices with limited space. They’re compact and relatively easy to install,but can block windows and aren’t as efficient as modern split systems.
If you’re not sure which setup is best for your space, our installation services cover everything from site surveys to complete fit-outs for homes and businesses across Bristol.
3. Measure Your Space and Cooling Needs
Every room is different, and the right AC unit must match your space’s size, shape, and heat load. British Thermal Units (BTUS) measure how much heat an air conditioner can remove. Choosing a unit with the correct BTU capacity is vital for energy efficiency and comfort.
For example:
- A 150 sq. ft. bedroom may only need 6,000 BTUS.
- A 400 sq. ft. lounge may need 12,000 BTUs.
- An open-plan office or kitchen could require 18,000+ BTUs, especially if there are heat-producing appliances.
Other key considerations include ceiling height, the number of occupants, window size, insulation, and how much direct sunlight the space receives. Poorly sized units can either run constantly (if too small) or short-cycle and waste energy (if too large).
4. Think About Room Layout and Installation Location
The layout of your home or office will influence the kind of system you need. For example, a wall-mounted unit in a bedroom must be installed high enough to distribute air evenly but not blow cold air directly onto the bed. Likewise, office systems should consider desk placement, meeting rooms, and server areas.
Split systems require proximity to an exterior wall for the outdoor compressor. Portable units need access to a vent or window. Ducted and ceiling cassette systems need space in your loft or ceiling voids for the ducts.
You’ll also want to consider:
- The noise impact in quiet spaces (see section 8)
- Electrical access and safety compliance
- Accessibility for maintenance
During a professional site survey, our engineers will help you identify the most suitable installation zones and configurations — whether it’s a low-wall unit for your conservatory or a ceiling-mounted system for a commercial site.
5. Prioritise Energy Efficiency Ratings
Energy efficiency not only saves money, it also reduces environmental impact. Air conditioners sold in the UK come with efficiency ratings like SEER (Seasonal Energy Efficiency Ratio) and EER (Energy Efficiency Ratio). Higher ratings mean the unit can cool more with less energy.
Modern inverter-driven systems, for example, automatically adjust their output depending on the cooling demand. This prevents overuse and maintains steady temperatures without frequent start-stop cycles. Units with A+++ ratings are among the most efficient, especially when paired with smart thermostats.
Look for features such as:
- Eco Modes – to reduce power use
- Sleep Modes – for quieter night-time running
- Smart Control – for remote scheduling and energy tracking
If you’re concerned about bills or want to make a sustainable choice, we can guide you toward the most energy-efficient models for your space.
6. Look for Helpful Additional Features
Modern air conditioners do much more than cool the air. They can significantly improve indoor comfort and air quality, especially important in homes with pets or people with allergies.
Key features to look out for include:
- Air Filtration – Advanced filters can remove pollen, dust, and even bacteria, making the air cleaner.
- Auto-Cleaning Functions – These reduce the build-up of mould and bacteria inside the unit.
- Dehumidification – Many ACs double as dehumidifiers, useful in damp UK conditions.
- Wi-Fi or App Control – Control your system remotely, set schedules, and monitor energy usage.
- Quiet Modes – For bedrooms, nurseries, or home offices, this can reduce the sound to as low as 19 db.
These added features often make a slight price difference but significantly improve day-to-day usability. Speak with our team if you’re unsure which options are right for your lifestyle.
7. Understand the Installation Process
Proper installation ensures your air conditioner works efficiently, safely, and complies with UK building regulations. At Controlled Climate, we handle every step of the process — from initial survey to final commissioning.
Our installation includes:
- A complete site survey and consultation
- Recommendations based on layout and usage
- Secure mounting of indoor and outdoor units
- Routing of refrigerant pipework
- Electrical integration with safety checks
- Pressure testing and system calibration
Our experienced installers work across Bristol and the South West, ensuring a hassle-free experience with minimal disruption.
8. Consider Noise Levels
Noise is often overlooked, but it becomes a significant factor when installing AC in bedrooms, offices, or quiet spaces. Fortunately, many modern systems are designed to operate at whisper-quiet levels.
Typical decibel (db) ranges:
- 19–25 db: Silent operation — ideal for bedrooms or nurseries
- 26–40 db: Normal sound range for most units
- 40+ db: Noticeable, especially in smaller or enclosed spaces
Portable units and older systems tend to be louder, while modern inverter systems significantly reduce sound output. During your consultation, we’ll recommend the quietest units for your space and preferences.
9. Think Long-Term: Servicing and Support
Air conditioning systems need regular maintenance to ensure peak performance and long-term reliability. Annual servicing keeps filters clean, refrigerant levels correct, and your system operating safely.
At Controlled Climate, we offer full maintenance packages that include:
- Filter replacement
- Electrical checks
- Coil cleaning
- Performance testing
This not only extends your system’s lifespan but also keeps energy costs down. For businesses, regular servicing ensures compliance with warranty and F-Gas regulations.
10. Ask the Experts
Choosing an air conditioner is a big decision, and expert advice can make all the difference. Whether you’re upgrading your lounge, fitting out a restaurant, or planning a multi-room system for an office, we’ll help you find a solution that fits.
Controlled Climate has over 25 years of experience delivering bespoke air conditioning systems across Bristol, Bath, and the wider South West. We offer personalised advice, on-site assessments, and professional installations with full support.
Contact Controlled Climate today to speak with a local expert and discover your ideal cooling solution.
FAQs: Buying the Best Air Conditioner
What is the best type of air conditioner for UK homes?
Split systems are the most popular choice due to their energy efficiency, quiet operation, and range of sizes to suit most properties.
Can I install an AC unit myself?
You can install a portable unit, but split and ducted systems require F-Gas certified professionals to comply with UK regulations and maintain warranty.
Is it cheaper to rent or buy a system?
Buying is more cost-effective over time. It also gives you access to warranties, servicing options, and resale value.
How do I choose the right size?
Use our BTU calculator to match the unit to your room size and usage. Our engineers can also assess your property during a survey.
How long does installation take?
Most domestic systems can be installed within a day. Larger or commercial systems may require two days or more, depending on the layout.
Serving Bristol and the South West
We proudly supply and install air conditioning systems across:
- Bristol
- Bath
- Weston-super-Mare
- Portishead
- Clevedon
Whether you’re looking to cool your home or optimise climate control in your workplace, we offer fast, friendly, and professional support tailored to your needs.
Ready to Find Your Ideal Air Conditioning System?
Still unsure which unit is right for your space? Contact Controlled Climate today and let our team guide you through the process, from selection to installation.