The questions UK homeowners actually ask.

Do heat pumps actually work in old British houses?

Yes; but only if they're sized and run correctly. The headline failure stories are almost always undersized radiators paired with an installer who set the flow temperature too low, or oversized units paired with one who set it too high. A high-temperature R290 unit (Vaillant aroTHERM plus, Daikin Altherma 3 R290) and a competent installer turn most Victorian terraces into perfectly comfortable heat-pump homes.

How does the £7,500 heat pump grant actually work?

The Boiler Upgrade Scheme (BUS) is a £7,500 grant paid to your MCS-certified installer, who deducts it from your invoice. You don't apply directly; the installer does. Eligibility requires a valid EPC with no outstanding insulation recommendations (loft and cavity), MCS certification, and your home being your main residence. The grant is currently committed through 2028.

Will a heat pump actually be cheaper to run than my gas boiler?

On a standard tariff, with a SCOP of 3.5 or better and current gas-vs-electric prices, a heat pump comes out roughly level; sometimes 10% cheaper, sometimes 10% more. On a heat-pump-specific tariff (Octopus Cosy, British Gas Heat Pump tariff), the gap typically widens to 20–30% cheaper than gas. The tariff is the lever, not the kit.

How loud is a heat pump outside?

Current R290 monoblocs (Vaillant aroTHERM plus, Octopus Cosy 6) run at around 31–35 dB(A) at 1 metre at low load; quieter than a fridge in the next room. Worst case at full output is 45–55 dB(A). Placement matters more than the spec: away from bedroom windows, on anti-vibration mounts, never in a tight rear yard that becomes an echo chamber.

Will I have to replace all my radiators?

Often, no. A good installer's design exercise tells you which rooms need upsized emitters and which don't. In a typical 1980s 3-bed, two or three radiators usually need to grow; the rest stay. High-temperature R290 units have made the 'rip out every radiator' story largely obsolete.

Do I need planning permission for a heat pump?

In England, most domestic air-source heat pumps are permitted development if the unit is below 1.5m³, sited more than 1m from a boundary, and at least 1m from any neighbouring window. Listed buildings, conservation areas and flats often require permission. Recent (2024+) reforms have eased the boundary requirement in many councils; always check before installing.

Why does MCS certification matter?

MCS certification is the only route to the £7,500 BUS grant; and the certification process forces installers to do a heat-loss survey, size correctly and document the install. The grant matters; the discipline matters more.

The grant is real. The technology is mature. The variable that decides your outcome is the person who installs it. Spend the time on that; everything else follows.