Is this a real MCS heat pump suitability survey?

No. This is a quick screening tool — think of it as a pre-survey. An MCS-accredited installer will run a full room-by-room heat loss, survey the radiators, and produce a specific design.

What EPC rating do I need for a heat pump to work?

There is no minimum EPC. A well-designed heat pump can run on an EPC E property with low flow temperatures and upgraded emitters. But the lower the EPC, the bigger the radiators and the bigger the unit — so upfront cost rises.

Why does radiator age matter?

Older compact (Type 11) radiators were sized for 70 °C+ boiler flow. Heat pumps run at 45-50 °C, so emitter output drops by ~30%. Radiators often need to be upsized or swapped to Type 22 or K3 to hit the required output.

What if I don't have outside space?

An external unit needs airflow clearance (typically 30 cm rear, 1 m front) and at least 1 m from a neighbour boundary under permitted development. Fully enclosed flats without garden access are usually unsuitable for air source.

Do I definitely need a hot water cylinder?

Yes for air source. Heat pumps produce hot water slowly relative to combi boilers, so the cylinder acts as a buffer. Allow 180-250 L depending on occupancy. A handful of high-temperature heat pumps claim combi-like operation but adoption is still very limited.

Are solid walls a deal-breaker?

No, but they push fabric heat loss up sharply. Internal or external wall insulation usually pays back quickly and lets you specify a smaller, quieter heat pump.

How accurate is the kW estimate?

The estimate uses floor area × EPC-band W/m² as a proxy. Expect ±30% accuracy. Always commission a full heat loss before purchase.

Does this cover ground source or water source?

Not directly — the scoring focuses on air source (ASHP). Ground source adds land requirements; water source adds riparian access. Both need different scoring.

Free calculator for engineers

Heat Pump Suitability Checker

Is it right for a heat pump? A 60-second screening before you commission a full heat loss. Get a verdict, the unit size, and a punch-list of what needs to change.

Heated floor area (m²)

EPC rating

Radiators

Outdoor space for external unit

Solid walls (no cavity)Space for a hot water cylinder

Excellent candidate

A heat pump will work well here with a standard design.

Estimated unit size

5kW

Back-of-envelope from floor area × EPC band. Final spec needs a full heat loss.

Next steps

Book an MCS-accredited installer for a room-by-room heat loss and detailed quote.
Spot-check older radiators for heat pump compatibility.

How it works

1
Enter property basics
Floor area, EPC rating, radiator age, available outdoor space.
2
Flag constraints
Solid walls, cylinder space — the two biggest retrofit blockers.
3
Get a verdict + action list
Score from excellent to unsuitable, ballpark kW, and the fix list to close the gap.

What actually decides heat pump suitability

Three things dominate: fabric performance (how much heat escapes), emitter capacity (whether the radiators can deliver enough heat at 45-50 °C), and outdoor space (whether the external unit can breathe and stay within noise limits). Everything else is secondary.

Fabric is usually the biggest swing. A pre-retrofit EPC F property might need 12 kW of heat; after cavity insulation and loft upgrade, the same house drops to 6 kW — a much smaller, cheaper, and quieter unit.

Emitters are the second. If you find 1980s Type 11 radiators, assume at least half will need upsizing. Budget for the swap alongside the heat pump itself — skipping this step is the most common cause of an underperforming system.

Common pre-assessment mistakes

Assuming high EPC = easy install. An EPC C property with tiny radiators still needs emitter work. The EPC rates the building fabric, not the heating system.

Specifying the unit before the heat loss. Unit size should come out of the heat loss, not a round number. An oversized unit will cycle inefficiently; undersized will leave the home cold on design days.

Ignoring noise placement. Permitted development caps unit noise at the boundary. A 1 m setback from the neighbour — plus a clear 1 m forward space — is usually the constraint that forces a specific product choice.

Tag it once. Get rebooked every year.

Stick a BoilerTag on the boiler. The homeowner scans the QR when the service is due — your name and number are right there. Your first 12 tags are free.

Get 12 free BoilerTags

Frequently asked questions

Heat loss calculator →

Room-by-room heat loss for detailed heat pump sizing.

Radiator BTU calculator →

Check whether each radiator has the capacity for 45-50 °C flow.