What Happens During a Boiler Upgrade Scheme Survey?

Most homeowners picture a quick look at the boiler and a handshake. A proper survey goes much further. Its measurements decide whether a heat pump keeps your home warm in January, or leaves you reaching for an electric heater.

Here’s what our surveyor does on the day, why each step matters, and how to get the most from the visit.

Why the Survey Comes First

You can’t claim the boiler upgrade scheme grant without a design built on real data from your home. MCS rules require a room-by-room heat loss calculation before any certified heat pump installation, and you’ll only get the grant through an MCS-certified installer.

The survey also replaces a step many homeowners still expect. EPCs rely on simplified assumptions and are not accurate enough to size a heat pump. That’s one reason the scheme dropped the EPC requirement in April 2026, but it means the survey now carries all the weight.

Inside the House: Room by Room

The surveyor works through every heated room with a tape measure or a scanning app. In each one they record:

• Wall, floor and ceiling dimensions
• Window and door sizes, plus the glazing type
• What the walls are made of, such as solid brick, filled cavity or timber frame
• Loft insulation depth
• Every radiator’s size and position

The results show how much heat each space needs in very cold weather. A north-facing bedroom with an old sash window might need twice as much heat as a similar-sized room on the sunny side.

Getting the walls wrong skews everything. If an old solid wall is treated like a modern insulated cavity wall, the calculation will show too little heat loss. Dig out any paperwork on past insulation work so the surveyor isn’t left guessing.

The Numbers That Shape Your System

Everything measured indoors feeds into three design decisions: heat pump capacity, design flow temperature and emitter sizing. Here’s what each one means for you:

• Capacity is the size of the heat pump. Too small and the house feels cold. Too large and the unit switches on and off constantly, wasting electricity.
• Flow temperature is how hot the water in your radiators runs. Heat pumps are most efficient at lower temperatures, commonly 45 to 55C, compared with the much hotter water an old boiler sends round.
• Emitters are your radiators. Water at a lower temperature gives off less heat, so some radiators may need to be bigger. The grant can contribute towards replacements where the survey shows a need.

Outside: Finding the Right Spot

Next, the surveyor heads outdoors to choose where the unit will go. They’re looking for good airflow, a stable base, a short pipe run to the house and space to service it.

Planning rules in England relaxed in May 2025. The one-metre-from-the-boundary rule is gone, so tighter gardens and terraced homes now have more options.

Noise is still checked carefully. Under permitted development, an installation must meet the noise limits in the MCS 020 a) standard, so the surveyor measures distances to neighbouring doors and windows. Wales runs its own planning rules, so we confirm the position for Welsh homes separately.

Hot Water, Electrics and Pipework

Back inside, the survey covers the parts most people forget about:

• Hot water cylinder. Does your current one suit a heat pump, and where would a new one go if not?
• Electrical supply. Can your fuse board and incoming supply handle the extra load?
• Pipework. Are the existing pipes wide enough to carry the higher water flow a heat pump needs?
• Controls. Where should the thermostat and smart controls sit?

How to Prepare for the Visit

A little preparation makes the visit faster and the quote more accurate:

1. Clear access to the loft, airing cupboard and fuse box.
2. Gather your recent heating bills, or oil and LPG delivery records.
3. Point out cold rooms, damp patches and draughts. These details shape the design.
4. Think about where you’d prefer the outdoor unit and cylinder, then tell the surveyor early.
5. Write down your questions. “What flow temperature are you designing for?” is a good one to start with.

After We Leave

You’ll get a quote showing the system design, any radiator or cylinder changes, the full price, the grant deduction and the balance you pay. Nothing goes to Ofgem until you agree.

Once you give consent, we apply for the voucher, secure approval and book the installation. You can spread the remaining balance through our monthly instalment plan.

Ready to Book Your Survey?

Your survey tells you more about your home’s heating than any online calculator can. It’s also the first step towards air source heat pump grants worth £7,500, or £9,000 if you’re replacing oil or LPG.