The short answer
For most garden rooms the best heating is electric: a wall-mounted panel or infrared heater on a thermostat for occasional use, or an air conditioning unit (an air-to-air heat pump) for a room used every day, because it uses far less electricity for the same warmth and cools the room in summer. A log burner can work, but the flue and fitting fall under the building regulations.
The right heater depends on two things: how often you will use the room, and how well it holds heat. A well-insulated office used five days a week needs something different from a hobby room used on Saturday afternoons. Get the insulation right first, then choose the heating.
The running cost sum
Almost every garden room heater runs on electricity. Under the Ofgem price cap for October to December 2026, the average unit rate is about 26p per kWh. A heater’s rating tells you how much it uses at full power, so a 1 kW heater on full for one hour uses 1 kWh, about 26p.
In practice a thermostat switches the heater on and off, so it rarely runs flat out all day. A small, well-insulated room may need a 1 to 1.5 kW heater; a large room with lots of glass may need 2 to 3 kW. Those are rough rules of thumb, and the builder should size it for your room.
Your options
Electric panel heaters
Slim convector panels on the wall, with a built-in thermostat and timer. They are cheap to buy, simple to fit, and warm the air quickly. Running costs are the plain sum above. They suit rooms used a few times a week.
Infrared panels
These warm people and surfaces rather than the air, a little like sunshine. They can feel comfortable at a lower air temperature and can be mounted on a ceiling, out of the way. They suit studios and offices where you sit in one place. Infrared is no more efficient per kWh than a panel heater; the saving, if any, comes from feeling warm sooner.
Oil-filled radiators
Portable and familiar. Slower to warm up but they hold heat. Fine as a stopgap, but a fixed heater is tidier and safer in a room you leave unattended.
Air conditioning (air-to-air heat pump)
A wall unit inside and a small fan unit outside. In heating mode it moves heat from the outside air into the room, so it gives out several times more heat than the electricity it uses. Manufacturers typically quote around three units of heat for each unit of electricity, depending on the outside temperature. It also cools the room in summer and dries the air.
It costs more up front, roughly £1,500 to £3,000 fitted by the guides we have checked, but for a room used most days it is usually the cheapest to run. If your garden room will face south with big glass doors, the cooling alone may make it worth it.
Electric underfloor heating
Mats under the floor give gentle, even warmth with nothing on the walls. They suit gyms and studios where wall space matters. They are slower to respond, and the floor finish has to be suitable. See our flooring guide for which floors work over underfloor heating.
Log burners
A small stove makes a garden room feel special, and there are plenty of good reasons people want one. There are also more rules:
- Fitting a stove and its flue is building work covered by the building regulations. Use a HETAS-registered installer, who can self-certify the work, or apply to building control.
- The flue needs safe distances from the timber frame, the roof and the cladding, and a non-combustible hearth.
- You need a carbon monoxide alarm and a supply of fresh air.
- Chesterfield Borough Council says Chesterfield is a smoke control area. You can only burn wood in a DEFRA-exempt stove, used with the fuels its maker specifies, or else burn an authorised smokeless fuel. Elsewhere in Derbyshire, ask your district council.
A stove also produces a lot of heat for a small room. A room that is too hot to sit in is a common complaint.
Comparison at a glance
| Heater | Upfront cost | Running cost | Best for |
|---|---|---|---|
| Panel heater | Low | The standard rate | Rooms used now and then |
| Infrared panel | Low to medium | The standard rate | Desks, studios, ceilings |
| Air conditioning | Higher | Lowest for daily use | Offices and gyms used most days |
| Underfloor (electric) | Medium | The standard rate | Gyms, studios, clear walls |
| Log burner | Highest once the flue is included | Fuel cost | Rooms for relaxing in winter |
Wiring and safety
Any heater beyond a plug-in needs a proper supply. Running a new circuit from the house to a garden room is notifiable electrical work under the building regulations, so it must be done or certified by a registered electrician. Make sure the cable is sized for the heater and everything else you will run at the same time. A heater, a kettle and a computer can add up quickly.
So which is best?
- Office used daily: air conditioning, with a small panel heater as a backup if you like.
- Studio or craft room a few days a week: an infrared or panel heater on a timer.
- Gym: often little heat is needed once you start moving, but cooling matters, so air conditioning again.
- Room for winter evenings: a log burner, if you accept the extra rules and cost.
The cost calculator lets you add air conditioning to your room’s price.
If you would like a builder to size the heating for a garden room in Chesterfield or Derbyshire, start with the form below.