Heat Pump Readiness Quiz

Why readiness matters more than the heat pump itself

A heat pump does not create heat — it moves it, delivering 3–4 units of warmth for each unit of electricity. But it delivers that warmth at low flow temperatures (35–45°C versus a boiler's 60–70°C), which changes everything about the house around it. Low-temperature heat needs time and surface area: big radiators or underfloor heating to release it gently, and a well-insulated, reasonably airtight envelope so the gentle heat is not instantly lost. Put a heat pump in a draughty, uninsulated house with small radiators and it will run constantly at high flow temperatures, achieving a SCOP of 2 instead of 3.5 — at which point it costs more to run than the gas boiler it replaced. The quiz above scores the seven things that determine which outcome you get.

This is the single most misunderstood point in UK retrofit. The failures you read about — the "heat pump that cost £400 a month" stories — are almost never faulty heat pumps. They are good heat pumps in unready houses, usually oversized to compensate for heat loss that should have been insulated away first. Readiness is not a nice-to-have; it is the difference between the technology working and an expensive disappointment. The good news: most readiness gaps are cheap to close, and every one of them pays for itself whether or not you ever buy the heat pump.

What each question is really asking

Loft insulation (270mm): the cheapest big win in the house. Heat rises; an uninsulated loft can account for a quarter of heat loss. If this answer is "no", the fix costs ~£500 and pays back in under two years — do it before thinking about anything else.

Wall insulation: the biggest single fabric item. Cavity fill (~£1,000, huge saving) if your walls are suitable — run the suitability checker first, because this one is safety-critical. Solid walls need internal or external insulation: bigger money, but transformative.

Glazing: single glazing is a readiness fail — not just for the heat loss but because cold window surfaces force you to run higher room temperatures for comfort. The glazing calculator is honest that the financial payback is long; for heat-pump readiness, it is about comfort at low flow temperatures.

Radiators: the question most people get wrong. Standard radiators sized for 70°C boiler water are roughly half the size a heat pump wants at 40°C. "Oversized" radiators (double or triple panel, or simply larger) or underfloor heating are what let the heat pump run at its efficient low temperatures. Radiator upgrades are cheap (£200–£400 per radiator fitted) and your installer should specify them as part of the heat-pump quote — if the quote does not mention radiators, the installer has not done the heat-loss calculation properly.

Outdoor space: the hard physical constraint. An air-source heat pump needs an outdoor unit roughly the size of a washing machine, with clear airflow and within permitted-development noise limits (42 dB at the neighbour's nearest window). No garden, yard, or flat roof access means air-source is off the table — ground-source needs far more space (or a borehole at £££). Flats should look at communal or high-heat-retention electric options instead.

Current system: replacing a gas or oil boiler is the standard BUS-grant path (£7,500). Replacing direct electric heating is an even stronger case — storage heaters at 24p/kWh are the most expensive common heating in Britain, and a heat pump quarters the running cost.

Draughts: a heat pump in a draughty house is trying to warm the street. The £120 DIY draught-proofing in our calculator is the highest-ROI readiness measure on this site.

The three verdicts, explained

READY (11+/14): your fabric can support low-temperature heating. Get the heat-loss calculation done, collect three MCS quotes, confirm BUS on each, and run the heat pump vs gas boiler calculator with your actual tariffs — it will tell you honestly if the running costs work at your electricity/gas price ratio.

ALMOST THERE (7–10): the most common result, and the most actionable. Typically it means the fabric is decent but the radiators are standard, or one insulation measure is missing. Close the 2–3 gaps — usually under £2,000 total, often under £1,000 — and re-take the quiz. Do not let an installer talk you into the pump before the gaps are closed; "we'll oversize it to compensate" is the sentence that precedes the £400-a-month stories.

NOT YET (under 7): fabric first, without apology. A heat pump now would be an expensive mistake. The upgrades are not wasted money — loft, walls, draughts and glazing all pay for themselves on a gas boiler too — they are just sequenced before the heat pump rather than with it. Revisit in a year or two via the retrofit planner.

The noise question

Modern air-source units run at 40–55 dB at one metre — roughly a quiet conversation — and permitted development requires under 42 dB at the nearest neighbour's window. In practice, neighbour noise complaints are rare with correct siting (away from bedroom windows, not boxed into a corner that amplifies sound). If your installer cannot show the noise calculation for your specific siting, that is a red flag — it is a required part of a compliant install, not an optional extra.

Ground-source and hybrid: the alternatives

Air-source is not the only heat pump. Ground-source (geothermal) is more efficient — SCOPs of 4+ are common because the ground stays ~10°C year-round — and quieter (no outdoor fan unit), but it needs either a large garden for horizontal ground loops or a borehole drilled 60–150m deep at £10,000–£15,000 just for the drilling. Total installs run £20,000–£35,000 before the £7,500 BUS grant. It suits rural properties with land and high heat demand, where the efficiency premium pays back; for a standard suburban semi it is overkill. Hybrid systems pair a small heat pump with the existing gas boiler, the pump handling mild weather and the boiler cutting in on the coldest days. Hybrids dodge the readiness problem — the boiler covers whatever the fabric cannot — but they keep you tied to gas, halve the carbon saving, and complicate the BUS grant position. They are a pragmatic halfway house for hard-to-insulate period homes, not the destination.

Whichever type, the readiness logic is the same: the better the fabric, the smaller and cheaper the system and the lower the running cost. Ground-source in a leaky house is just an expensive way to heat the street more efficiently.

Costs: the full picture

A typical air-source install: £9,000–£14,000 before the £7,500 BUS grant, leaving £1,500–£6,500 to fund — plus radiator upgrades (£1,000–£3,000 if needed) and any readiness fabric work. Compare with a gas boiler replacement at £2,500–£4,000. The honest comparison, including running costs at your tariffs, is in the heat pump calculator — which is also where you discover whether your 24p/6p price ratio makes the pump cheaper or more expensive to run. Go in with the readiness score from this quiz and the running-cost maths from that calculator, and no salesperson can bluff you.