Electrics for a garden room: rules and costs

Who can do the work

The Commission for Regulation of Utilities (CRU) is clear: electrical work in your home must be carried out by a registered electrical contractor. That includes the supply to a garden room. They must give you a completion certificate confirming it meets the safety standards.

How power gets there

1. A new circuit at your fuse board, with the protection the electrician specifies.
2. An armoured cable, usually in a duct, buried in a trench to the garden room.
3. A small board in the room, feeding sockets, lights and heating.
4. A spare duct alongside for ethernet or fibre, laid while the trench is open.

Inside the room

• Sockets at desk height for screens and chargers, and one for a heater.
• Lighting that works on dark winter afternoons, plus an outside light for the path.
• Heating on its own circuit if it's a large load, like an air-to-air heat pump.
• A smoke alarm, and in a garden home, the full fire detection the Building Regulations require.

What it costs

Costs rise with distance, hard digging (through concrete or paving), a board upgrade at the house, and the number of sockets and lights. Ask whether the garden room supplier's price includes the connection from the house. Many don't.

Big loads: heat pumps, saunas, chargers

A sauna heater, a large heat pump or an electric car charger in the garden room draws much more power than an office. Tell the electrician what you plan to install from the start, so the cable and circuit are sized for it. Upgrading later means digging the trench again.