Wall-mounted indoor air conditioning unit installed high on the wall of a London room

Home office
air conditioning

Home office air conditioning that keeps you cool through the working day and stays quiet enough for calls. Usually fitted in a day.

  • Free survey and a fixed written price
  • Sized from a calculation, not from the floor area
  • One day on site for most single rooms
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Air conditioning we have fitted

Our own jobs, photographed on site. Real rooms, real outdoor positions, nothing from a catalogue.

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A home office needs about 12 percent more cooling than a bedroom of the same size, because of the equipment and the occupant. A typical 10 to 12 square metre office needs 2.0 to 2.5kW and costs 2,400 to 3,200 pounds fitted.

Running it through a working day costs roughly 12 to 22 pence an hour at current rates, which is less than most people assume and less than a fan heater in winter.

An outdoor air conditioning unit we fitted on brackets on a London rear wall

Your estimate

£2,400to£3,200

Supplied, fitted, commissioned and certificated. Includes VAT.

Price it for this room

One room, so the two things that move the number are how big it is and which kind of indoor unit you want.

How big is the room?
Which indoor unit?

Last step: what number should we call with your fixed price?

Every figure on this site is an estimate built from the quotations we issued in 2026 and our own installation experience. It is not a quotation. The price you are given after the free survey is the price you pay.

From first call to cool rooms in three steps

  1. Free survey

    We measure the rooms, find the outdoor position and check permission for your address.

  2. A fixed written price

    Units, pipework and electrics itemised. The number does not move unless the job does.

  3. Fitted in a day

    One room a day, tested in every mode, and shown to you before we leave.

Read the full guide: 6 sections, about 3 minutes

What size a home office needs

Using the same model as the sizing calculator on this site, with the 12 percent uplift for office use applied on top of aspect, floor and glazing.

Home offices: worked sizing examples
RoomHow it works outUnit
Box room office, 8 m², north facing8 × 0.14 = 1.12, less 10% aspect, plus 12% use2.0kW
Small office, 10 m², east facing10 × 0.14 = 1.40, plus 12% use2.0kW
Office, 12 m², south facing, first floor1.68, plus 18% aspect, 5% floor, 12% use2.5kW
Garden room office, 14 m², large glazing1.96, plus 18% glazing, 12% use2.5kW
Loft office, 14 m², west facing1.96, plus 18% aspect, 30% loft, 12% use3.5kW

The equipment load, which is bigger than it looks

Nearly all the electricity that goes into a computer comes back out as heat. A laptop with a dock and two monitors is commonly 100 to 150W continuous, a desktop with a graphics card can be several hundred, and a person adds around another 100W.

In a large room that is negligible. In a nine square metre box room with the door shut it is the dominant load in the morning before the sun reaches the window, which is why home offices get uncomfortable earlier in the day than the rest of the house.

It is also why an office is a room where the calculation is worth doing rather than assuming a small room needs a small unit.

Quiet enough for a call

The number to ask for is sound pressure at the lowest fan speed. The best wall units are 19 dB(A) and most good ones are between 19 and 24, which is below the noise floor of a typical room and will not reach a microphone.

What does reach a microphone is a unit that keeps starting and stopping, and that is an oversizing problem rather than a model problem. A correctly sized unit settles into a continuous low output and stays there.

Position helps too. A unit discharging across the room rather than down onto the desk keeps both the air movement and the noise away from where you are sitting.

What it actually costs to run a working day

A 2.5kW unit holding a small office at temperature does not draw 2.5kW. Once the room is down to temperature an inverter unit modulates to whatever the room is losing, which for a small internal office is commonly 300 to 600W.

At current electricity rates that is roughly 12 to 22 pence an hour, so a full working day is usually under two pounds and often well under. There is a calculator that uses your own tariff on the running costs page.

In winter the same unit heats the office for less than a plug-in heater costs, which for a room the central heating reaches badly is often the bigger saving.

What it costs

Home offices: installed prices
ScopeSystemInstalled price
Box room or small office2.0kW wall unit£2,400 to £3,200
Standard home office2.5kW wall unit£2,400 to £3,200
Loft or garden room office3.5kW wall unit£2,550 to £3,500
Office plus one bedroom2 unit multi-split£4,300 to £5,800
Annual serviceAny make£95 plus VAT

Every figure on this site is an estimate built from the quotations we issued in 2026 and our own installation experience. It is not a quotation. The price you are given after the free survey is the price you pay.

Other rooms

Home offices: common questions

Will people hear the air conditioning on a video call?

Not from a good unit running at its lowest speed. 19 to 24 dB(A) is below the background level of most rooms and well below what a laptop microphone picks up at arm's length.

What does get picked up is a unit cycling on and off, because the change is what a noise-suppression algorithm cannot mask. That is a sizing problem, and it is avoidable.

How much does it cost to run in a home office?

Roughly 12 to 22 pence an hour for a small office once the room is at temperature, so usually well under two pounds for a working day. The first twenty minutes cost more than the rest of the day, because that is when the unit is working hardest.

The running costs page has a calculator that uses your own tariff rather than an average.

Is a portable unit good enough for one room?

For occasional use in a rented flat where nothing can be fitted, it is better than nothing. For a room used every working day it is a poor trade: a portable unit has to vent through a window, the hose lets warm air back in, it is typically three to four times louder than a fitted split system, and it uses considerably more electricity for the same cooling.

The noise is usually what decides it for a home office. A portable unit in a room you take calls in is not workable.

Can I heat the office with it in winter?

Yes, and for a home office it is often the best reason to fit one. A home office is frequently a room the central heating serves badly, and heating one room with an air conditioner is far cheaper than heating the whole house to warm it, and cheaper than a plug-in electric heater in that room.

Free survey for a home office

We measure the room, do the heat load calculation properly, and give you a fixed written price with the model on it. If a smaller unit is the right answer, we will tell you.

Monday to Friday 9am to 7pm, Saturday 10am to 3pm, Sunday closed

How many rooms do you want cooled?

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