Garden rooms and home offices are the two rooms in a house most likely to be unusable exactly when you need them. Both for the same reason: they are small, heavily glazed, lightly built, and they have nothing to soak up heat.
By mid-morning in June a garden room is warmer than the garden. By two in the afternoon it is somewhere you visit rather than work in.
Why they overheat so badly
A garden room is mostly glass, and glass lets heat in far faster than a brick wall does. The structure is timber rather than masonry, so there is no thermal mass to even out the day. The roof is usually flat, shallow and takes sun from mid-morning onwards. And because they are built airtight and well insulated, what gets in stays in.
A home office in the house has a milder version of the same problem, plus a computer, monitors and a person generating heat in a small room with the door shut.
Fans move the hot air about. Opening the doors lets in noise, insects and, on a hot day, hotter air.
What we install
Almost always a single wall-mounted unit sized for the room. Garden rooms are small enough that one modest unit does the job, and in a building with limited wall space it goes high on the wall where nothing else is competing for room.
Where the ceiling allows it, a ducted system keeps the walls clear entirely, which matters more in a small room than a large one. That is a decision for the survey.
The electrics are the thing to check
This is the part people do not expect. A garden room is usually fed by a single armoured cable from the house, sized for lights and sockets rather than for air conditioning as well.
Sometimes there is plenty of capacity and nothing needs doing. Sometimes the supply is already working hard and it needs looking at properly before anything is installed. We check it at survey, because finding out afterwards is nobody’s idea of a good day.
Where the outdoor unit goes
Usually on the garden room itself, or on the ground beside it, which keeps the pipe run short and the installation tidy. Two things we think about: how close it sits to your neighbour’s boundary, and whether you will be looking at it from the house.
Planning permission is not normally needed, but there are conditions on siting and noise, and they are stricter in a conservation area.
It is really about winter too
Most people call us about summer and end up valuing it more in January. A garden room with no central heating is cold and slow to warm, and electric heaters are expensive and take a while.
The same unit works as a heat pump in reverse, reaching a comfortable temperature within minutes and moving roughly three to four units of heat for every unit of electricity it uses. For a room with no radiator, that is usually the cheapest practical way to heat it.
Common questions
Is my garden room too small to bother?
Small rooms are the ones that overheat fastest, so no. If anything they are the easiest and cheapest to put right.
Will it be quiet enough to work in?
Yes. A modern inverter unit on a low setting is background noise at most, and once the room is at temperature it barely runs. We size it so it does not have to work flat out, which is what makes units noisy.
Can you do it if the garden room is already built?
Yes, and most are. It is more straightforward than people expect.
What about a garden room that has not been built yet?
Then it is worth talking to us early. Running the pipework and a properly sized supply during the build costs very little and saves doing it twice.
Book a free survey
Free survey, fixed price before anything starts. Call 020 3488 4657, message us on WhatsApp, or use the contact page.
You can also read what a single-room installation costs, or see how ducted systems keep the walls clear.