Everything starts with a room-by-room heat loss calculation. Not an estimate off the floor area, not a number from a spreadsheet — an actual survey where we measure the rooms, look at the walls, and work out what each one needs on the coldest day of the year. That calculation tells us the size of the unit and the size of every radiator. It is the whole job. An installer who quotes you a heat pump without doing it is guessing.
The design flow temperature is the number that matters most. Every degree you can take off it makes the system cheaper to run. A modern house with underfloor heating might run at 35 degrees. A 1930s semi with the original radiators might need 55, which is a bad heat pump and a good argument for changing some rads. A solid-wall Edwardian villa might need fabric work before a heat pump makes any sense at all. Those are three different conversations and we would rather have the honest one at survey.
The Boiler Upgrade Scheme pays £7,500 towards an air source heat pump in England and Wales, and because we are MCS certified we claim it from Ofgem ourselves. It comes off your quote as a discount — you never handle the money and there is no form for you to chase. You need an EPC issued in the last ten years, and as of this year an outstanding loft insulation note on it no longer blocks the grant the way it used to.
Planning is simpler than it was. The rules changed on 29 May 2025 and the old requirement to keep the unit a metre from your boundary was scrapped, which opened up a lot of terraces and narrow semis that were shut out before. The outdoor unit can be up to 1.5 cubic metres on a house, and a detached house can now have two. What has not relaxed is noise: the MCS 020 sound calculation has to show 37 dB(A) or under at your nearest neighbour's window. On a big plot that is a formality. On a terrace it is the number that decides the job, and we run it before we quote.
