What is a heat pump COP?

COP = Coefficient of Performance = heat output ÷ electricity input. A modern air-source heat pump (ASHP) runs at 2.8–3.5 COP averaged over a UK heating season (the seasonal version is called SCOP). For every 1 kWh of electricity it pulls in roughly 3 kWh of heat. Ground-source heat pumps (GSHP) hit 3.5–4.5 SCOP but cost double to install.

What is the BUS grant?

The Boiler Upgrade Scheme (England & Wales) gives £7,500 toward an air-source or ground-source heat pump installation, replacing a fossil-fuel boiler. Scotland has the Home Energy Scotland Grant (up to £7,500 + £7,500 interest-free loan). Both schemes require MCS-certified installs and EPC C+ ratings. Confirmed running through 2028.

Are heat pumps cheaper to run than gas boilers?

Depends on the price ratio. A heat pump with SCOP 3.0 needs electricity to be no more than 3× the gas price per kWh to break even. UK gas is ~6p/kWh and electricity ~28p/kWh — a 4.7× ratio, so a heat pump is currently more expensive on standard tariffs. With a heat pump tariff (Octopus Cosy ~13p/kWh off-peak) it's roughly equal to gas. EU and US rates vary widely.

Will my house need new radiators?

Often yes. Heat pumps run at lower flow temperatures (35–55°C vs 60–80°C for gas), so you need larger surface area to deliver the same heat. About 30–50% of older UK homes need at least some radiator upgrades. Underfloor heating is ideal. A good MCS install includes a heat-loss calculation per room and recommends upgrades.

Is a heat pump worth it in 2026?

After the BUS grant a heat pump install is typically £6K–£10K out of pocket vs £2.5K–£4K for a new gas boiler. Running cost parity is achievable on a heat pump tariff. Carbon savings are immediate and large (~3 tonnes CO₂/year vs gas). With UK gas prices rising and electricity decarbonising, the long-term economics favour heat pumps. For early adopters it's a 10–15 yr financial decision and a good environmental decision.

♨️ Varmepumpe vs Gaskedel Lommeregner

15-year total cost comparison of an air-source heat pump versus a gas boiler. Includes UK BUS grant, fuel prices, maintenance and CO₂ savings.

Årlig Heat Demand (kWh)UK gns. ~12.000 kWh. Lille lejlighed ~6K, stort hus 18K+.

Valuta

♨️ Varmepumpe (ASHP)

Install Cost

Statsligt tilskud

SCOP (efficiency)

Elektricitet price (per kWh)

Årlig servicing

🔥 Gaskedel

Install Cost

Boiler Efficiency (%)

Årlig servicing

Gas price (per kWh)

Årlig fuel inflation (%)

⚠️ Estimat only. Real SCOP depends on radiator size, insulation, weather and installer skill. Get an MCS heat-loss survey before committing. Heat-pump-specific tariffs (Octopus Cosy, OVO Varmepumpe Plus) can dramatically improve running costs not modelled here. Not financial advice.

Varmepumpe vs Gaskedel — The Decision in 2026

The economics of replacing a UK gas boiler with an air-source heat pump (ASHP) depend on three numbers: the install cost gap (after grants), the electricity-to-gas price ratio, and the SCOP (seasonal efficiency) you'll actually get. Get all three right and a heat pump matches or beats gas on lifetime cost. Get them wrong and you'll pay more.

Installationsomkostninger (UK maj 2026, fuldt monteret)

New combi gas boiler: £2,500–£4,000
System gas boiler with cylinder: £3,500–£5,500
Air-source heat pump (8–12 kW): £10,000–£16,000 (before grant)
Ground-source heat pump: £18,000–£35,000 (before grant)
Boiler Upgrade Scheme (BUS) grant: £7.500 mod ASHP/GSHP

Så et typisk UK-installationsgab er £6.000–£8.000 ekstra for en varmepumpe efter tilskuddet.

Running Cost Maths

For at producere 12.000 kWh varme i en UK-bolig med gennemsnitligt udstyr:

92% efficient gas boiler: 12,000 ÷ 0.92 = 13,043 kWh of gas × 6p = £783/year
SCOP 3.0 heat pump: 12,000 ÷ 3.0 = 4,000 kWh of electricity × 28p = £1,120/year on standard tariff
Same heat pump on Octopus Cosy off-peak (~13p/kWh): ~£520/year — beats gas decisively

The Tariff Lever

Varmepumpetariffer er den dræbende funktion. Octopus Cosy opkræver ~13p/kWh i tre lavbelastningstidsvinduer, når varmepumpen kan udføre det meste af sit arbejde med at oplade en buffertank eller køre med højere flowtemperaturer. OVO Heat Pump Plus begrænser elektricitet til gasequivalentpriser for verificerede varmepumpebrugere. Med disse tariffer matcher eller underskrider varmepumpedriftsomkostningerne gas.

Fungerer en varmepumpe i mit hus?

Insulation: EPC C or better is best; D is workable; E or worse — fix insulation first
Radiators: 30–50% of homes need at least some larger rads (heat pumps run cooler flow temperatures)
Outdoor space: ~1 m × 1 m ground space + 1 m clearance for ASHP outdoor unit
Hot water: en varmtvandsbeholder er nødvendig (kombi-kedler uden en har brug for udskiftning af VVS)
Power supply: enkelt-fase normalt fint; tjek med installatøren

Kulstofbesparelser

A typical heat pump cuts heating-related CO₂ by ~70%. UK gas emits 0.182 kg CO₂/kWh; UK grid electricity is now ~0.21 kg CO₂/kWh and falling. So 12,000 kWh of heat from gas → 2.4 tonnes CO₂; from a SCOP 3.0 ASHP → 0.84 tonnes — a ~1.6 tonne annual saving. Over 15 years that's ~24 tonnes — equivalent to taking a car off the road for 6 years.

Hvad denne lommeregner ikke inkluderer

Radiator/cylinder opgraderingsomkostninger (ofte £500–£3.000 for ældre hjem)
Heat-pump-specific electricity tariffs (Octopus Cosy, OVO Varmepumpe Plus)
Synergi med solceller (gratis el om dagen øger varmepumpeøkonomien massivt)
Fremtidige gasprisstigninger (Ofgem-loftet steg ~50% over 2021–2024)
Ejendommens værdistigning / EPC-vurderingsforbedring

⚠️

Vigtig bemærkning: Få altid lavet en MCS-varmetabsundersøgelse, inden du bestiller en varmepumpe – underdimensionerede enheder cykler og yder dårligt; overdimensionerede enheder er spild af penge. Indhent tre tilbud fra MCS-certificerede installatører. BUS-tilskuddet kræver, at installatøren ansøger på dine vegne. Kombiner med vores Solpanel Lommeregner if you're considering both — together they transform running costs.

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