Electrics and gas
Underfloor heating manifolds are connected to the heat pump and none of the loops were balanced on the visit. What was not commissioned?
The underfloor loops were not commissioned. Manifolds connected to the heat pump were seen, and none of the loops were balanced on the visit, so flow on each loop, the actuators and the settings that make the system match its design were not set or checked. Commissioning is the installer's task of proving those circuits. The survey does not do it. Approved Document L is energy-performance guidance for building work. This visit has not issued a building-regulations certificate, and it has not tested heat-pump efficiency.
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 manifold splits the heat-pump flow into loops under the floor. Balancing means each loop is given a flow, often on a small gauge at the manifold, so one room does not starve another. Seeing the pipes connected only shows a connection. It does not show the gauges were set, that the loops are clear, or that the pump and the floor were matched. Dust on the gauges, missing caps, or a blank control screen would still be notes, not a commissioning sheet.
Ask the solicitor for any commissioning certificate, design sheet or warranty, and keep those papers off the survey text. The survey does not decide grant eligibility, and it must not be asked to invent one. A heating engineer can balance the loops if you instruct that work later. Tell a lender the visit saw the manifolds and did not balance them. Do not describe the floors as proved because the pipes were present.
What should you ask your surveyor?
- Were the loop flows left unbalanced on this visit?
- Has a commissioning sheet been seen, or only the manifolds?
- Does this survey issue a building-regulations certificate for the heating?
What are the typical next steps?
- Treat the underfloor loops as not commissioned.
- Ask the solicitor for any commissioning or design papers.
- Do not describe the connection as a completed test.
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 patch of floor prove the loops were balanced?
No. A warm patch, if one was felt, only shows some heat reached that spot. It does not show each loop has its intended flow, or that the manifold was set up as designed. The visit did not balance the loops. Ask for the commissioning paper. Do not turn a warm board into a finished installation.
Is the heat pump's efficiency settled by the manifold being connected?
No. Efficiency was not tested. A connection between the pump and the manifold is plumbing in view, not a performance result. Approved Document L guides building work on fuel and power. It is not a reading this survey took from the machine. The loops stay uncommissioned, and the pump's performance stays unmeasured.