Heat Pump vs Boiler – Which Should You Choose in 2025?
The Big Heating Decision…
If you’re looking to replace your current boiler or install a new heating system, you’re likely wondering: Should I install a heat pump or a boiler?
With rising gas prices, new regulations, and government incentives for renewables, air source heat pumps are becoming a preferred alternative to traditional gas and oil boilers.
In this in-depth guide, we’ll compare heat pumps and boilers based on:
- Installation cost
- Running cost
- Efficiency
- Maintenance
- Lifespan
- Carbon footprint
- Grant availability
By the end, you’ll know which system is best for your home and budget.
What’s the Difference Between a Heat Pump and a Boiler?
| Feature | Boiler | Heat Pump |
|---|---|---|
| Fuel | Gas, Oil or LPG | Electricity (powered to extract ambient heat) |
| Efficiency | 80-95% | 300-500% |
| Emissions | High (fossil fuels) | Low (renewable energy) |
| Cost to Run | Higher (gas/oil prices) | Lower (even lower with insulation & solar) |
| Installation Cost | £2,500-£4,500 | £9,500-£14,500 (minus BUS Grant) |
| Grant Available | ❌ | ✅ Boiler Upgrade Scheme saving £7,500 |
| Lifespan | 10-12 years | 20+ years |
Installation Cost Comparison
🔹 Gas or Oil Boiler:
- Typical install: £2,500 – £4,000
- Less disruption (no cylinder if combi)
- Often included in new builds or replaced like-for-like
🔹 Air Source Heat Pump:
- Typical install: £11,000 – £13,500
- With Boiler Upgrade Scheme: £3,500 – £6,000 out-of-pocket
- May include hot water tank + radiator upgrades
- Eligible for £7,500 government grant (installer should handle grant paperwork and help reduce upgrade costs with expert system design)
Running Cost Comparison
| System | Average Annual Cost (3-bed home) | Notes |
|---|---|---|
| Gas Boiler | ~£900 | Based on 90% efficiency |
| Oil Boiler | £1,100 | Higher fuel cost |
| LPG Boiler | £1,300 | Most expensive |
| Heat Pump (ASHP) | £800-£950 | COP of 3.5-4.5 (350%-450% efficiency) |
➡️ Pairing a heat pump with solar PV can reduce running costs even further.
➡️ Heat pumps benefit more from smart tariffs and off-peak rates.
Efficiency – Heat Pumps Win Clearly:
Boilers burn fuel to generate heat. Heat pumps move heat instead of generating it — so they use far less energy.
- Boilers: ~90% efficiency (lose ~10% of energy)
- Heat Pumps: 300–500% efficiency (COP of 3–5)
This means for every 1kWh of electricity used, a heat pump can deliver up to 4–5kWh of heat.
Emissions & Eco Impact
Gas and Oil Boilers
- Use fossil fuels
- Emit CO₂ and NOx
- Subject to 2035 UK gas boiler phase-out in new builds
- High carbon footprint
Heat Pumps
- Use grid electricity (increasingly renewable)
- No combustion, no flue, no direct CO₂
- Eligible for government grants to accelerate Net Zero
Switching to a heat pump can reduce your carbon footprint by 50–70%.
Maintenance & Reliability
🔧 Boilers
- Annual gas safety check required
- Prone to breakdowns (especially older units)
- Parts availability varies by manufacturer
- Expected lifespan: 10–15 years
🔧 Heat Pumps
- Fewer moving parts
- No combustion = less wear
- Just a simple yearly service
- Expected lifespan: 15–20+ years
TLC Renewables offers full annual servicing plans and warranty-backed systems.
Space Requirements
System | Space Needed |
Combi Boiler | Fits in a kitchen cupboard |
Heat Pump | Outdoor unit + hot water cylinder |
If you’re used to a compact combi boiler, installing a heat pump will require space for:
- Outdoor unit (like an air-con box)
- Indoor cylinder (typically airing cupboard or utility room)
However, modern systems can often be retrofitted with minimal disruption.
Heat Pump vs Boiler: What’s Right for You?
Category | Best Option |
Upfront Cost | Boiler |
Long-Term Saving | Heat Pump |
Efficiency | Heat Pump |
Emissions | Heat Pump |
Grant Available | Heat Pump |
Ease of Install | Boiler |
Future-Proof | Heat Pump |
Our Expert Recommendation:
If you want a lower carbon, cheaper-to-run, future-proof heating system, a heat pump is the clear winner — especially with the current £7,500 Boiler Upgrade Scheme grant.
If you’re replacing an old gas, LPG, or oil boiler and your home has decent insulation, switching to a heat pump is a smart move.