Last updated: February 2026 | By Evolving Home Team
Can't Get a Heat Pump? Here Are Your Options
Heat pumps are the government's preferred heating solution — but they're not right for every home. Solid walls, listed buildings, no outdoor space, or existing undersized radiators can all rule out a standard installation. Here are the real alternatives.
Why Some Homes Can't Have Standard Heat Pumps
Solid stone or brick walls
~8 million UK homesHeat pumps work best in well-insulated homes. Solid walls (common in pre-1919 terraces and rural stone cottages) lose heat so fast that the heat pump runs constantly, achieving poor efficiency. Without solid wall insulation (£8k–£25k), a heat pump may not be viable.
Listed building / conservation area
~400,000 listed buildings in EnglandExternal wall insulation and many external alterations require listed building consent. External units for heat pumps can also be refused on visual grounds. Many listed buildings are locked out of standard retrofit pathways.
No outdoor space for an external unit
Particularly common in dense urban areasAir source heat pumps need an external unit roughly the size of a large washing machine with clear airflow. Flats, houses with no garden or small outdoor space, or terraced streets with no rear access may not have suitable locations.
Noise concerns or neighbour objection
Case-by-caseHeat pump units produce 40–60dB of noise — comparable to a refrigerator. For houses where units must be close to windows, bedrooms, or neighbouring properties, this can be a practical problem.
Existing radiators too small
Most pre-1990s homesStandard air source heat pumps work best at lower flow temperatures (45–55°C). Older radiators sized for 70–80°C boiler output may struggle to heat rooms adequately. Re-radiating the whole house adds £3,000–£8,000.
If one or more of these applies, a standard air source heat pump may be impractical, prohibitively expensive, or simply refused permission. That doesn't mean you're stuck with a gas boiler.
Your Alternatives
Tepeo Zero Emission Boiler (ZEB)
Thermal StorageThe ZEB stores thermal energy in a high-density ceramic core during off-peak electricity hours (typically 11pm–6am). It then releases that stored heat through the day via a water circuit — directly compatible with existing radiators and hot water tanks. It looks and connects like a conventional boiler.
- ✓Drop-in replacement for gas boiler — same connections, same radiators
- ✓Charges at off-peak electricity rates (Octopus Go: ~7p/kWh vs 27p/kWh peak)
- ✓Silent — no outdoor unit
- ✓Works in houses where heat pump isn't viable
- ✓MCS recognition and any grant route must be confirmed with the installer
- ✓Zero direct combustion emissions
- –Higher electricity consumption than a heat pump (COP ~1 vs 3 for ASHP)
- –Requires overnight electricity rate tariff to be cost-effective
- –Relatively new technology — limited long-term reliability data
- –Currently ~£7,000–£10,000 installed
Infrared Heating Panels
Radiant Electric HeatInfrared panels emit radiant heat that warms objects and people directly, rather than heating the air. They can be mounted on walls or ceilings, are completely silent, and have no moving parts. Each panel is independently controlled.
- ✓Very low installation cost (£150–£400 per panel, self-install possible)
- ✓Silent, no maintenance
- ✓Heats objects not air — feels warmer at lower air temperature
- ✓Ideal for rooms used intermittently
- ✓No planning permission required
- –COP of 1 — uses more electricity than a heat pump for equivalent heating
- –Not cost-effective as whole-house heating on standard tariff
- –Works best paired with solar PV and battery
- –Not eligible for BUS scheme
Solar Thermal for Hot Water
Renewable Hot WaterSolar thermal collectors on the roof heat a fluid that transfers energy to your hot water cylinder. A 4m² flat plate collector can provide 50–70% of annual hot water demand. Works alongside an existing boiler or heat pump for backup.
- ✓Very low running cost — sun is free
- ✓Long system life (20–25 years)
- ✓Reduces hot water energy bill by 50–70%
- ✓Can work alongside existing boiler or heat pump
- ✓Reduces heat pump demand if combined
- –Limited to hot water — cannot heat the home directly
- –Not eligible for BUS scheme (scheme is for space heating)
- –Requires cylinder with solar coil
- –Summer oversupply can be wasted
High-Temperature Heat Pumps
Heat PumpStandard air source heat pumps struggle above 55°C flow temperature. High-temp variants (e.g., Vaillant aroTHERM plus 75°C, Daikin Altherma 3 R HT) can reach 70–75°C, making them compatible with existing standard radiators without re-radiating.
- ✓Works with existing undersized radiators
- ✓May fall under standard BUS heat-pump categories if rules are met
- ✓Lower COP than standard ASHP but better than electric resistance heating
- ✓Eliminates need for re-radiating (saving £3k–£8k)
- –Higher running cost than low-temperature ASHP (lower COP at high temps)
- –Still needs outdoor unit space
- –Typically 10–15% more expensive to buy than standard ASHP
CO₂ (R744) Heat Pumps
Heat PumpR744 (CO₂) is a natural refrigerant with extremely high volumetric capacity. CO₂ heat pumps can achieve COP 3+ at outdoor temperatures down to -20°C — dramatically outperforming conventional R410A/R32 systems in cold weather. Also produce higher flow temperatures naturally.
- ✓Excellent cold-weather performance (-20°C operation)
- ✓Natural refrigerant — no GWP concerns
- ✓High flow temperatures (up to 90°C) — works with any radiator
- ✓Future-proof: refrigerant phase-out won't affect R744 systems
- –Higher system pressure requires specialist installation
- –Limited installer expertise in UK (growing rapidly)
- –Higher upfront cost (£12,000–£18,000 installed)
- –Most units larger than R32 equivalents
Cost Comparison Summary
| Option | Installed Cost | BUS Grant | Net Cost | Annual Saving |
|---|---|---|---|---|
| Tepeo ZEB | £7,000–£10,000 | Confirm category on GOV.UK | Full install until voucher confirmed | £200–£500 |
| High-Temp Heat Pump | £9,000–£14,000 | £7,500 if eligible | Full install until voucher confirmed | £300–£800 |
| CO₂ (R744) Heat Pump | £12,000–£18,000 | £7,500 if eligible | Full install until voucher confirmed | £400–£1,000 |
| Solar Thermal | £3,000–£6,000 | No | £3,000–£6,000 | £100–£250 |
| Infrared Panels (whole house) | £2,000–£5,000 | No | £2,000–£5,000 | Varies with solar |
BUS (Boiler Upgrade Scheme) categories for England & Wales currently include standard heat-pump £7,500, residential air-to-air £2,500, and rural off-gas biomass £5,000. Eligible off-gas oil/LPG properties may receive £9,000 for air-to-water or ground-source heat pumps (time-limited; confirm on GOV.UK). Confirm current funding on GOV.UK. Eligibility is not assessed on this page.
Which Should You Choose?
The right answer depends on your home type, budget, and constraints:
- Can't change radiators, listed building, solid walls: Tepeo ZEB is a common drop-in shortlist item — zero combustion; confirm any grant category separately.
- Have existing radiators but can do some work: High-temperature ASHP avoids full re-radiating and may use the standard BUS heat-pump category (£7,500) if rules are met.
- Cold climate or want future-proofing: CO₂ (R744) heat pumps are the premium option — expensive now but the most future-proof technology.
- Want to reduce hot water bills cheaply: Solar thermal is low-tech, long-lived, and pairs with any heating system.
- Have solar PV and want supplementary heating: Infrared panels are often the cheapest-to-install option; running cost can be low when powered by surplus solar, but they are not free heat and suit supplementary use more than whole-home heating.
Related guides
Heat Pumps UK Guide
ASHP and GSHP design checks, BUS standard grant context (£7,500 illustrative; eligibility not assessed), and measured running-cost inputs.
Home Insulation Guide
Loft, cavity, solid-wall, and floor insulation compared.
Reduce Heating Bills
Flow temperature, controls, and honest bill-saving caveats.
UK Energy Grants 2026
Current scheme status including BUS standard illustrative £7,500 (eligibility not assessed), evidence requirements, and what to verify before applying.