If the consumer unit has no spare way, the air conditioning quote is not firm until a competent electrician has said how the circuit will be fed. That may be a new board, a rearrangement, or a supply limit that needs the distribution network operator. Do not double up breakers, and do not run a split from an adaptor. The electrician's answer comes before the equipment order. The refrigerant circuit, when you get there, needs an F-gas certified company. In England the outdoor unit still has to meet Planning Portal conditions.
A closed board with no spare way
A full board is a full board. A quote that quietly includes a connection to the existing consumer unit has assumed a spare way you do not have. The cost of a board change can matter as much as the indoor unit. Get that cost into the open first, from an electrician who will certify their own work. A board change is a real cost, not a footnote.
Photos of a closed board are enough to start. Do not remove covers, and do not pull meter seals. The electrician can see what is inside. You can take a provisional equipment price. Do not treat it as firm, and do not order plant, until the electrician has said how it will be fed.
Spare ways, earthing and who does which job
They look at spare ways, the rating of the board, the earthing, the cables, and what the house already draws: cooker, immersion, chargers, an existing heat pump. A couple of small splits on a healthy single-phase supply is often straightforward once there is a way to connect them. A full board plus a whole-house set of units may be a supply question for the distribution network operator.
This page does not set an amp ceiling. Supplies differ. Anyone who gives you a universal limit without seeing the board is guessing.
With a circuit route agreed, the installer can price models, pipes and condensate. Keep the two competences clear. F-gas certification covers the refrigerant circuit. It does not entitle someone to rebuild a consumer unit. Some companies employ both skills. Ask who does which part. Electrician first, firm air conditioning price second.
A new board is not a planning consent
Outdoor siting is unchanged by the board. Read the Planning Portal conditions in England. A new board does not create permitted development. A full board is your consumer unit. A looped supply is the network cable, and that is a distribution network operator matter. An electrician can tell you which one you are looking at.
Frequently asked questions
Can the installer just squeeze the unit onto an existing breaker?
No. Do not double up circuits to fake a spare way. Do not share a breaker to invent a space. A competent electrician needs to design the connection, which may mean a new board.
Should I accept an air conditioning quote before the board is seen?
You can take a provisional equipment price. Do not treat it as firm, and do not order plant, until the electrician has said how it will be fed.
Is a full board the same as a looped supply?
No. A full board is your consumer unit. A looped supply is the network cable, and that is a distribution network operator matter. An electrician can tell you which one you are looking at.
Can the air conditioning installer rebuild the consumer unit?
F-gas certification covers the refrigerant circuit. It does not entitle someone to rebuild a consumer unit. Do not feed the unit from a plug adaptor. Some companies employ both skills. Ask who does which part.
Core buying guides
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Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.