Electrics and gas
The survey notes a monobloc air-source unit but never a flow temperature. Has the efficiency of that heat pump been measured?
The efficiency has not been measured. The survey notes a monobloc air-source unit and never a flow temperature, so the water leaving the machine was not read. Efficiency needs measured temperatures and known running conditions, and none of that was taken. The unit was identified from what could be seen. Its performance was not. The survey does not turn a nameplate into a test result, and it has not decided the heat pump is efficient or inefficient.
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?
A monobloc air-source unit puts the main refrigeration circuit in the outdoor box and sends heated water indoors. Flow temperature is the temperature of that water as it leaves toward the system. Without it, nobody knows whether the machine was running hard, ticking over or off. A badge with a model name is not a reading. Approved Document L is energy-performance guidance for building work. This visit does not issue a building-regulations certificate and did not apply that guidance as an efficiency test.
The Boiler Upgrade Scheme is a grant route in England and Wales toward a heat pump or biomass boiler, not in Scotland or Northern Ireland. The survey does not decide eligibility and quotes no grant figure. Ask the installer or a service engineer if you need flow temperature and efficiency discussed. Tell a lender the monobloc was seen and not performance-tested. Do not copy a brochure efficiency into the survey. No such figure was measured on the day.
What should you ask your surveyor?
- Was a flow temperature read on the monobloc?
- Has efficiency been measured, or only the unit identified?
- Does a model badge replace a temperature reading?
What are the typical next steps?
- Treat efficiency as unmeasured.
- Ask an engineer if you need flow temperature taken.
- Do not quote a brochure performance figure as a survey result.
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
Is a nameplate on a monobloc a flow-temperature reading?
No. A nameplate identifies the manufacturer and the model. Flow temperature is a live reading of the water leaving the unit, and the survey never recorded one. The machine may have been off or between cycles. Either way, no figure was taken. Efficiency stays unmeasured. Do not treat printed output claims on a badge as the day's result.
Does identifying the unit decide a grant toward it?
No. The Boiler Upgrade Scheme is a grant route in England and Wales toward a heat pump or biomass boiler, not in Scotland or Northern Ireland. The survey does not decide eligibility and quotes no grant figure. Noting a monobloc is not an application. Efficiency was not measured, so performance cannot be borrowed as a reason to claim a grant in this report.