Heather Campbell
With rising energy bills, you may be considering swapping your boiler for a heat pump to cut winter costs.
In this article we cover:
- Your home heating upgrade options
- Upfront cost comparison: boilers vs heat pumps (including grants)
- Technical performance: how do boilers and heat pumps compare?
- The benefits of a heat pump in terms of comfort, carbon emissions and property value
But before diving in, it’s worth asking whether upgrading your insulation alone — something you’d likely need to do before installing a heat pump anyway — would be a more cost-effective first step.
Another question is whether a modern condensing boiler might actually offer better lifetime value than a heat pump in certain cases.
Cost of boiler versus heat pump in the UK
England and Wales
The UK government currently offers support through the Boiler Upgrade Scheme (BUS), providing grants of:
[adrotate banner="58"]- £7,500 towards the cost of installing an air source heat pump
- £7,500 for a ground source heat pump
Available in England and Wales only, this grant is aimed at helping homeowners move away from fossil fuels. The scheme doesn’t need you to upgrade insulation beforehand — but it is a good idea so that the heat pump performs efficiently.
By contrast, replacing your existing boiler with a new high-efficiency condensing gas or oil boiler may cost significantly less upfront, but it does mean remaining tied to fossil fuels and vulnerable to future carbon pricing.
Scotland
The Home Energy Scotland Grant and Loan currently offers loans for heat pumps and biomass boilers:
- Up to £15,000 (£7,500 grant plus up to £7,500 loan) for air source and ground source heat pumps. Qualifying rural properties can get an extra £1,500 grant.
- Up to £15,000 (£7,500 grant plus up to £7,500 loan) for biomass boilers.
Northern Ireland
If you live in Northern Ireland, contact NI Energy Advice to find out more about funding available to help improve your home’s energy efficiency.
Technical comparison: boiler versus heat pump
Heat pumps work most efficiently in well-insulated homes. Because they operate at lower temperatures than boilers, they need your property to hold on to heat effectively. This means that insulation and airtightness upgrades may be essential.
For example, upgrading from double to triple-glazed windows, adding cavity or external wall insulation and ensuring airtightness can dramatically improve your home’s thermal performance — and are often necessary to make a heat pump work well.
Heat pumps:
- Extract renewable heat from the air or ground
- Have lower running costs than gas or oil boilers when used in an energy-efficient home
- Are eligible for government grants/loans in England, Wales and Scotland
- Can lower your carbon footprint significantly
Modern boilers:
- Cost less to install
- Can be easier to retrofit into older homes without major insulation works
- Have higher running costs and emit more CO₂ over time
If your home is not well insulated, a boiler upgrade may make more financial sense in the short term, although you’ll remain exposed to rising fuel costs and carbon taxes.
The benefits of a heat pump
Comfort
Homes upgraded with insulation, airtightness measures and a heat pump tend to be more comfortable. Heat is distributed evenly, and systems with mechanical ventilation with heat recovery (MVHR) maintain consistent indoor air quality and temperature without draughts.
Carbon emissions & future-proofing
Electricity in the UK is increasingly sourced from renewables. Choosing a heat pump now means your heating system will get greener over time as the grid continues to decarbonise.
In contrast, oil and gas boilers lock you into fossil fuels — and into the cost of carbon as climate policies tighten.
Home value
While data for the UK is still emerging, studies suggest that improving a home’s EPC (Energy Performance Certificate) rating can lead to a higher resale value. A better energy rating also makes the property more attractive to buyers who are conscious of running costs and environmental impact.
Example: heat pump retrofit in a 1970s home
Consider a typical 150sqm 1970s detached bungalow. To make a heat pump viable, the home would likely need:
- Cavity wall insulation (or internal/external wall insulation if not possible)
- Loft insulation upgrade
- High-performance triple-glazed windows
- Airtightness improvements
These upgrades could cost tens of thousands of pounds — though they bring long-term energy savings and comfort.
Running cost comparisons (based on April 2024 UK average energy prices):
- Electricity: ~24p/kWh
- Heating oil: ~10p/kWh
- Gas: ~7p/kWh
While electricity costs more per unit, heat pumps typically operate at 300 per cent + efficiency (COP of 3+), meaning 1 unit of electricity can provide 3+ units of heat — potentially levelling the playing field, especially in well-insulated homes.
Verdict
New builds: Heat pumps are a no-brainer. UK Building Regulations now require new homes to be highly energy efficient and in many cases to include low-carbon heating. A well-designed new home might not even need a conventional heating system at all.
Existing homes: If you’re planning a full renovation or deep retrofit, installing a heat pump can make sense — especially when insulation upgrades are already part of the plan.
However, if your home has average or poor thermal performance and you’re not planning a deep retrofit, then replacing your boiler with a modern condensing model may be a more practical and affordable short-term solution — even if it’s not the lowest-carbon one.
