Electrics and gas
The controller shows a weather-compensation curve that the surveyor did not adjust. Has the heating design been approved?
No. The weather-compensation curve has not been approved as a heating design. The surveyor saw it on the controller and did not adjust it. A curve only sets how flow temperature should follow the outdoor sensor. Seeing that line does not show the emitters were sized to the rooms. This visit did not log temperatures or open a commissioning record. The Boiler Upgrade Scheme is a grant route in England and Wales, not a sign-off of this curve. Approved Document L is guidance for building work, and this survey does not issue a building-regulations certificate.
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 compensation curve is a setting, not a measured result. The controller uses an outdoor reading to choose a flow temperature. If the curve sits too low the rooms stay cool. If it sits too high the heat pump may run hotter than the house needs. Changing a live control is outside a home survey, so the curve was left as found. No efficiency test was carried out. The report can say a curve was on the screen. It cannot say that curve matches the heat loss of these rooms.
Ask the solicitor for any commissioning sheet that names who set the curve and when. A lender may treat heating as a service, and this report is not a design certificate. If you want the curve checked against the rooms, that is a heat-pump specialist, not a second pass of this visit. Do not tell anyone the design was approved because a screen was photographed. The survey has not verified an installer registration from this display alone.
What should you ask your surveyor?
- Was the outdoor sensor connected, or only a curve drawn on the controller?
- Does any handover sheet name the curve that was actually commissioned?
- Would altering the curve later affect a warranty the survey has not read?
What are the typical next steps?
- Ask the seller for the commissioning sheet and the controller manual.
- Keep the photographed curve separate from any claim of design sign-off.
- If comfort is the worry, instruct a heat-pump specialist to review the setting.
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 high energy band prove this curve is right?
No. An energy certificate models a dwelling from assumptions. It does not read this controller, confirm the outdoor sensor, or prove the curve was commissioned for these emitters. A favourable band and an unapproved curve can exist together. The survey has not used the certificate as a heating test.
Can the surveyor turn the curve up as part of the report?
No. A home survey records the control it found. Changing a live weather-compensation curve is installer work and can alter how the heat pump and the emitters run. This visit left the setting alone on purpose. Any later change belongs with a specialist, not as an edit inside the report.