These questions are for any installer, wherever you live. They are not a test; a good surveyor will expect most of them and answer without hesitation. What you are listening for is whether the answers are specific to your house.
The design
- "How are you working out the heat loss, and will I get it room by room?" MCS certified installers design to MIS 3005-D, the heat pump design standard. A good answer explains what is being measured: walls, windows, floors, roof, ventilation.
- "What size of heat pump does that point to?" The answer should come from the heat loss, not from the number of bedrooms.
- "What flow temperature will you design for?" This decides which radiators are big enough. Ask why that temperature was chosen.
- "What room temperatures are you assuming?" If you like some rooms warmer than others, say so now.
Inside the house
- "Which radiators would change, and to what?" Ask for a radiator schedule with the quote.
- "Where would the cylinder go, and how big would it be?" Settle the space question at the survey, not on fitting day.
- "Will any pipework need changing?" And where new pipes would run.
- "What controls would you fit, and how will they be set up?"
Outside
- "Where would the outdoor unit go, and why there?" Consider looks, access, noise and the pipe run.
- "Does that position meet the planning conditions, including MCS 020 a)?" In England, an air source heat pump installed without a planning application must comply with the MCS 020 a) sound calculation. Ask for it with the quote.
- "Will my electricity supply need work, and who tells the network operator?" The installer handles the notification, but an upgrade could affect cost and timing.
The grant and the timing
- "Are you registered for the Boiler Upgrade Scheme, and which grant amount would apply to my home?" For most homes that qualify it is £7,500. Check the answer against the MCS register.
- "When would you apply, and when could you fit?" After the installer applies, Ofgem emails you and you have 14 days to confirm. The voucher then has a time limit for the work.
- "How long would the heating and hot water be off?"
Terms and aftercare
- "Which consumer code are you in?" Then check it yourself on the code's site.
- "What workmanship warranty do you give, and who stands behind it?" RECC members, for example, must give at least 2 years with financial protection.
- "What deposit do you take, and how is it protected?"
- "What will you hand over at the end?" The MCS certificate, commissioning records, the design figures and the warranties.
- "Who do I call if something goes wrong after you leave?"
After the visit
Write down what you were told while it is fresh, and compare it with the quote when it arrives. If the quote leaves out something you discussed, ask. Then use the check sheet for the firm, and the quote comparison once you have two or three quotes. If any answer worried you, the warning signs page may explain why.
What a good answer sounds like
A good answer to "how are you working out the heat loss?" mentions measuring each room, the walls and windows, the insulation, and the temperatures assumed, and offers you the figures in writing. A weak answer is "a house this size usually needs about this much". A good answer to "where would the outdoor unit go?" weighs the pipe run, access, noise and neighbours, and mentions checking the sound calculation. A weak answer is simply the most convenient wall.
Preparing for the visit
- Note the rooms you like warmer or cooler than the rest.
- Think about where you would and would not accept the outdoor unit and the cylinder.
- Find any records of insulation work, window replacements or extensions.
- Know where your consumer unit, stopcock and current boiler are.
- Allow enough time to be there for the whole visit.
If the surveyor will not answer
Some questions genuinely need the calculation done first, and a surveyor may say they will confirm the figures with the quote. That is reasonable, as long as the figures then arrive. What is not reasonable is a refusal to put the design in writing at all. If that happens, it belongs on your list of warning signs.
After two or three visits
Once you have seen two or three surveyors, compare not only their quotes but how they surveyed. Did each measure every room? Did they look at the radiators, the loft and the electrics? Did they explain their reasoning? The firm whose survey was most thorough is often the one whose design you can rely on, whatever the price.
Questions about the outdoor unit
Ask where the surveyor proposes to put the outdoor unit and why. Ask how far it will be from the nearest neighbour's door or window, because that distance feeds the sound calculation that permitted development depends on. Ask how the pipes will run from the unit into the house, where the hot water cylinder will go, and whether any cupboard space will be lost. If the surveyor suggests more than one position, ask for the trade-offs in writing.
Questions about the electrics
Ask whether the electricity supply needs any change, and whether the firm will notify the network operator, or apply to it first, before the heat pump is connected. The answer depends on the size of the unit and on your supply, so a clear and specific reply is a good sign.
Write the answers down during the visit, or ask the surveyor to put them in the quote. Answers given on the doorstep are easy to forget and hard to rely on later; answers in writing become part of what you are comparing between firms.