Office Air Conditioning

Offices get warm. People, computers, screens, printers and lighting all give off heat, and large windows add heat from the sun. An office that feels fine in the morning can be uncomfortable by the afternoon. Air conditioning holds the temperature steady through the day and, with a system that heats as well as cools, keeps the office warm in winter too.

Our team designs and installs air conditioning for offices, from a single room to larger buildings, and for home offices. For larger buildings, see our page on VRF and VRV systems.

What the Law Says About Office Temperature

The Workplace (Health, Safety and Welfare) Regulations 1992 require the temperature in indoor workplaces to be reasonable. Health and Safety Executive guidance says it should normally be at least 16°C, or 13°C if much of the work involves rigorous physical effort. There is no legal maximum, but conditions still need to be reasonable for the people working there.

Which System Suits Your Office?

• Wall-mounted units. The simplest and lowest-cost option for a single office or a small open-plan space. See wall-mounted air conditioning.

• Ceiling cassettes. Ideal where there is a suspended ceiling. Compact cassettes fit a standard ceiling tile and spread air in four directions, which suits open-plan offices. See ceiling cassette air conditioning.

• Ducted systems. Hidden above the ceiling, with only grilles on show. A good fit for meeting rooms and reception areas where appearance matters. See ducted air conditioning.

• Multi-split systems. Several indoor units, such as offices, a meeting room and a kitchen, run from one outdoor unit. See multi-split air conditioning.

• VRF systems. For larger buildings with many rooms, where one system serves many indoor units and different areas are controlled separately.

Getting the Size Right

Offices often need more cooling than their floor area suggests, because every person and every computer adds heat. A busy open-plan office needs a proper calculation of the heat from people, equipment, lighting and windows, which we carry out at the survey. Our guide to what size air conditioner you need explains the basics.

Positioning in an Office

• Position units so air does not blow directly onto anyone sitting at a desk.

• In open-plan offices, two smaller units or cassettes often give a more even temperature than one large unit.

• Plan the controls. A controller in each area, or one central controller, makes it easy to set sensible temperatures and avoid units running in empty rooms.

• Keep outdoor units secure, accessible for servicing and away from neighbouring windows where possible. See our guide to air conditioning outdoor units.

Rules for Business Air Conditioning

• F-gas leak checks. Systems containing refrigerant equivalent to 5 tonnes of CO2 or more must be leak checked at least every 12 months by a certified engineer, and records must be kept. Our guide to R32 refrigerant explains the F-gas rules.

• Energy inspections. In England and Wales, air conditioning systems with an effective rated output of more than 12 kW must be inspected by an accredited energy assessor at least every five years. This includes several smaller units that add up to more than 12 kW. It is often called a TM44 inspection.

• Your lease. If you rent your office, check your lease before any work, as alterations to the building, especially outside walls, usually need the landlord's consent.

• Planning. An outdoor unit on a commercial building may need planning permission, so check with your local council.

Air Conditioning for a Home Office

A spare bedroom or box room used as an office can get very warm with a computer, screens and a person in it all day. Rooms at the top or back of the house are often the worst.

• Size. Most home offices need a 2.0 to 2.5 kW wall unit.

• Noise. Choose a quiet unit and run it on a low fan speed during calls. The quietest wall units are rated at around 19 dB(A) on their lowest setting. See the quietest air conditioners.

• Position. Keep the airflow off your desk and chair.

• Heating. In winter, the same unit lets you heat just the room you are working in.

• Garden offices. An insulated garden office can be air conditioned in the same way. See garden office air conditioning.

What Does Office Air Conditioning Cost?

For a home office, one room typically starts from around £2,500 installed, and most single-room systems are fitted in a day. For business premises, the cost depends on the size of the space, the number and type of indoor units, the pipe routes and access to the building. We give you a clear written quote after a free survey.

Frequently Asked Questions

Can office air conditioning also heat the office?

Yes. Most modern systems heat as well as cool, and they heat efficiently because they move heat rather than make it. Read more about air conditioning as a form of heating.

Can the office system also cool a server cupboard?

It is better to give a server or comms cupboard its own unit. That equipment produces heat day and night, all year round, so it needs cooling even when the office system is off or heating.

How often does office air conditioning need servicing?

We recommend a service at least once a year, or twice a year if the system is used for heating. In a busy or dusty office, the filters may need cleaning more often. See our air conditioning servicing page.

Call 01772 288651 or use the form below to book a free survey. We will look at the space, recommend the right system and give you a clear written quote.

Last updated: November 2026.