Electrics and gas
An immersion heater is the backup for the heat pump and the consumer unit was not tested. What electrical point remains open?
The electrical point that remains open is the untested supply to the immersion and the consumer unit that feeds it. The survey saw an immersion heater described as the backup for the heat pump. It did not test the consumer unit, the immersion circuit, or the controls that would bring the heater on. Seeing the cylinder does not show the wiring is safe or that the heater will run if the pump stops. That backup stays electrically unproved.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
An immersion is an electric heater in the hot-water cylinder. As a backup it is only useful if the circuit, the switch and the thermostat are actually in working order. None of those was tested. A label saying backup is not a meter reading and not a trip of the device at the consumer unit. The heat pump's own electrics, where they share that unit, were likewise not tested. The visit stopped at what could be seen.
Ask an electrician, on a separate instruction, to test the consumer unit and the immersion circuit if you need that backup proved. Tell your solicitor the home survey did not test electrics, so any form about the installation is not this report. Do not tell a lender the immersion will cover a heat-pump failure. The survey recorded the heater's presence. It has not decided the electrical backup works. Any certificate, if one exists, belongs in the solicitor's pack rather than in this note.
What should you ask your surveyor?
- Was the consumer unit left untested, including the immersion circuit?
- Did anyone operate the backup switch during the visit?
- Are electrical certificates held outside this survey?
What are the typical next steps?
- Treat the immersion backup as seen, not as tested.
- Ask an electrician to test the unit and the immersion circuit.
- Do not tell a lender the backup was proved to work.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does a warm cylinder show the immersion has been on?
Not reliably. A warm cylinder can be the heat pump, residual heat, or the immersion, and this visit did not separate those sources. No electrical test was done. Temperature on the outside of the cylinder is not a test of the circuit. The backup remains electrically unproved.
Is the heat pump's own fuse the same open point?
If that fuse sits in the consumer unit, it was not tested either, because the unit as a whole was not tested. The question left open is electrical, not a verdict on the pump's refrigeration circuit. The survey did not decide which device protects the immersion. An electrician would need to identify that on a later visit.