Replace Gas Boiler With A Heat Pump: Costs, Pros & Cons

If you’re a UK homeowner or landlord looking to replace your gas boiler with a heat pump, you’re likely seeking ways to reduce carbon emissions, improve energy efficiency, and potentially lower long-term heating costs. 

This guide covers everything from financial implications to practical considerations, helping you decide if switching to an air source heat pump (ASHP) is right for your property in areas like London, Brighton, Oxford, Southampton, Bristol, or Cardiff.

Can You Replace Your Gas Boiler With a Heat Pump?

Yes, you can replace your gas boiler with a heat pump in the UK, and it’s a viable, increasingly popular option for most homeowners and landlords, especially with ongoing government support like the Boiler Upgrade Scheme providing up to £7,500 towards air source heat pump (ASHP) installations in England and Wales as of 2026.

The vast majority of UK properties with an existing gas boiler can make the switch successfully, provided the home meets basic suitability criteria.

Modern air source heat pumps perform reliably even in colder UK winters, delivering efficient heating down to low temperatures while integrating with existing radiators (often with minor upgrades like larger emitters or better insulation for optimal results). 

There’s no outright ban on replacing gas boilers in existing homes—in fact, the government continues to encourage the transition through grants and incentives to support net-zero targets, with no phase-out for replacements in occupied properties.

Key factors that make replacement straightforward include:

• Property type and efficiency — Homes with decent insulation (EPC rating C or above preferred) and standard wet heating systems work best, as heat pumps deliver lower flow temperatures (typically 35-55°C) compared to a gas boiler’s higher output. Poorly insulated older properties may need upgrades first for cost-effective running, but many Victorian or Edwardian homes in areas like London, Brighton, or Oxford have been successfully converted.
• Space requirements — An outdoor unit (about the size of an air conditioning unit) needs placement with adequate airflow and clearance—recent planning rule relaxations have made this easier in urban and semi-urban settings across Southern England, Greater London, South West England, and South Wales.
• Eligibility for support — To qualify for the £7,500 Boiler Upgrade Scheme grant, your property must have a fossil-fuel heating system (like gas, oil, or LPG) being replaced, you must own the home (or be a private landlord for eligible rentals), and the installation must use an MCS-certified installer. Hybrid systems combining gas and heat pumps don’t qualify for the full grant.
• No major barriers for most — Even in flats, listed buildings, or commercial properties, solutions exist with careful planning, and professional surveys confirm feasibility quickly.

For properties in the regions such as London, Brighton, Oxford, Southampton, Bristol, and Cardiff—this transition is particularly accessible. 

A free, no-obligation air source heat pump installation quote from EE Renewables includes a detailed site assessment to confirm if your home is ready or what simple improvements (like insulation top-ups) would make it ideal, ensuring you get accurate cost estimates and grant application support right from the start. 

Many homeowners find the process smoother than expected, with installations completed in just a few days and long-term benefits in lower carbon emissions and energy security.

Tip: Many of the practical differences involved in switching systems are explored in our comparison of air source heat pumps vs gas boilers, which helps clarify efficiency, cost, and long-term value trade-offs.

Why Replace Your Gas Boiler with a Heat Pump?

Replacing your gas boiler with a heat pump offers a sustainable alternative to traditional fossil fuel heating systems, aligning with the UK’s net-zero goals and providing efficient renewable energy solutions for homes and commercial properties. 

As energy prices fluctuate and environmental concerns grow, many UK residents in Southern England, Greater London, South West England, and South Wales are opting for this upgrade to future-proof their heating. 

Heat pumps extract heat from the air, delivering up to 300-400% efficiency compared to a gas boiler’s typical 90%, meaning for every unit of electricity used, they produce three to four units of heat.

This shift not only supports low-carbon heating but also qualifies for government incentives, making it an attractive option for landlords managing rental properties or homeowners in older buildings seeking better insulation integration. 

These efficiency gains make more sense when you understand how air source heat pumps work, as they move existing heat rather than generating it through combustion.

If you’re in regions served by experts like EE Renewables, requesting a free air source heat pump quote tailored to your location—such as Brighton or Bristol—can provide personalised insights into how this change fits your setup.

What Are the Costs to Replace a Gas Boiler with a Heat Pump in the UK?

The costs to replace a gas boiler with a heat pump in the UK typically range from £8,000 to £15,000 for an air source heat pump installation in an average home, before applying any grants or incentives. These figures include supply, labour, and any necessary system modifications, but they can vary based on property size, location, and existing infrastructure.

Breakdown of Installation Costs

• Unit and Materials: The heat pump itself costs £4,000-£8,000, plus radiators or underfloor heating upgrades if needed for optimal performance.
• Labour and Setup: Professional installation by MCS-certified engineers adds £2,000-£5,000, covering outdoor unit placement and integration with your hot water system.
• Additional Upgrades: Homes may require £1,000-£3,000 for improved insulation or larger radiators to handle the lower flow temperatures of heat pumps.

Accurate heat loss calculations also determine what size air source heat pump you need, helping prevent unnecessary upgrades or inflated running costs.

Running costs are another key factor: while electricity is pricier per unit than gas, heat pumps’ high efficiency can lead to annual savings of £200-£400 compared to an older gas boiler, especially with smart tariffs or solar PV integration. For commercial buildings, costs might scale up to £20,000+, but tax reliefs like enhanced capital allowances can offset this.

After grants, many pay just £500-£7,500 net, making it feasible for properties in South Wales or Greater London. To get accurate figures, consider a site-specific assessment from EE Renewables. We specialise in these regions.

Tip: Whether these costs translate into long-term savings depends heavily on whether your home is suitable for a heat pump, particularly insulation levels and heat retention.

What Are the Pros of Replacing Your Gas Boiler with a Heat Pump?

The pros of replacing your gas boiler with a heat pump include significant environmental and financial benefits, making it a smart choice for eco-conscious UK homeowners and landlords aiming for sustainable property management. 

Heat pumps reduce carbon footprint by up to 80% compared to gas systems, supporting renewable energy transitions and potentially increasing property value through higher EPC ratings.

Here are the key advantages:

• Significant reduction in carbon emissions — Up to 80% lower CO₂ output compared to gas boilers, helping meet UK net-zero targets and future-proofing your property.
• High energy efficiency — Coefficient of Performance (COP) of 3–4, meaning 3–4 units of heat produced for every unit of electricity used—far more efficient than a gas boiler’s typical 90%.
• Lower long-term energy bills — Potential annual savings of £200–£400 (or more with solar PV and smart tariffs), especially in well-insulated homes.
• Cooling capability in summer — Many air source heat pumps can provide reversible cooling, adding comfort without separate air-conditioning units.
• Versatile hot water supply — Reliable domestic hot water heating integrated with the system.
• Quieter indoor operation — No noisy boiler indoors; the main unit is located outside.
• Fewer moving parts and lower maintenance — Reduced breakdown risk and simpler servicing compared to gas boilers.
• Improved comfort — Consistent, even low-temperature heating ideal for modern lifestyles and underfloor systems.
• Higher property value and EPC rating — Attractive to eco-conscious buyers and helps achieve better Energy Performance Certificate scores.
• Compliance benefits for commercial properties — Meets stricter building regulations and sustainability standards.
• Expert local support — In areas like Southampton, Cardiff, Bristol, Oxford, Brighton, and London, EE Renewables deliver high-quality, tailored installations.

What Are the Cons of Replacing Your Gas Boiler with a Heat Pump?

The cons of replacing your gas boiler with a heat pump revolve around initial hurdles like higher upfront expenses and potential home adaptations, which might deter some UK property owners. 

Installation can cost 2–3 times more than a new gas boiler without grants, and not all homes are immediately suitable without upgrades like better insulation or pipework changes.

Here are the main drawbacks:

• Higher upfront cost — Installation typically £8,000–£15,000 before grants (2–3 times more than a new gas boiler), although the Boiler Upgrade Scheme reduces this significantly.
• Need for home upgrades in some properties — Older or poorly insulated homes may require larger radiators, better insulation, or pipework changes to perform efficiently at lower flow temperatures (35–55°C vs. 70–80°C for gas boilers). In properties where radiator changes aren’t practical, a high temperature air source heat pump can provide boiler-like heat output while still reducing emissions.
• Slower heat-up times — Feels less responsive in cold snaps or uninsulated properties, though modern units work effectively down to -15°C.
• Outdoor unit requirements — Needs adequate space and airflow; produces moderate noise (40–60 dB), which can be noticeable in very quiet or densely packed urban areas like parts of London.
• Potential for higher running costs if home is inefficient — Savings depend on good insulation and electricity tariffs; poorly optimised setups may not reduce bills.
• Electricity price sensitivity — Running costs tied to electricity rates, which can fluctuate more than gas prices.
• Longer payback period — Typically 5–10 years depending on energy prices, usage, and grants received.
• Installation disruption — Work takes 3–5 days; landlords may face tenant inconvenience during the process.
• Planning permission in some cases — Required in conservation areas, listed buildings, or flats (though recent rule changes have eased restrictions).
• Space and aesthetic considerations — Outdoor unit visible on wall or ground, which may not suit every property’s appearance.

These points help highlight the realistic trade-offs so UK homeowners and landlords in Southern England, Greater London, South West England, and South Wales can make an informed decision. 

What Is the Installation Process Like When Replacing a Gas Boiler with a Heat Pump?

The installation process when replacing a gas boiler with a heat pump involves a structured, professional approach lasting 3-5 days, ensuring seamless integration into your UK home or commercial building’s heating system. It starts with a site survey by certified installers to assess insulation, space, and electrical capacity.

Next, the old boiler is removed, and the outdoor ASHP unit is positioned (requiring about 1m clearance, though 2025 rules eased boundary restrictions). Indoor components, like a hot water cylinder, are fitted and connected to existing radiators or underfloor systems. Electrical and plumbing work follows, with system testing for efficiency and safety.

Minimal disruption occurs, but temporary heating alternatives might be needed. 

How Can Government Grants Help with the Costs of Replacing a Gas Boiler with a Heat Pump?

Government grants can significantly help with the costs of replacing a gas boiler with a heat pump by offsetting upfront expenses through schemes like the Boiler Upgrade Scheme (BUS), making low-carbon heating accessible for UK properties. 

The BUS provides a £7,500 grant for ASHP installations in England and Wales, applied directly by installers, reducing net costs to £500-£7,500 for eligible homes.

Eligibility requires owning the property, replacing a fossil fuel system, and meeting insulation standards—no income tests apply. Additional support includes zero-VAT on installations until 2027 and potential ECO4 funding for low-income households. For commercial buildings, enhanced schemes offer up to £15,000 including loans.

In areas like Cardiff or London, combining these with local incentives maximises savings.

Tip: For a full breakdown of pricing beyond boiler replacement, our guide to air source heat pump costs explains how installation, running expenses, and grants combine over time.

Ready to Replace Your Gas Boiler with a Heat Pump?

Ready to replace your gas boiler with a heat pump? Taking the next step towards efficient, renewable heating is straightforward with expert guidance from EE Renewables Ltd. 

As specialists in air source heat pump installations across Southern England, Greater London, South West England, and South Wales—we offer free, tailored quotes to match your property’s needs.

Contact EE Renewables today to schedule a no-obligation site visit and explore how grants and custom solutions can make your transition affordable and seamless. Upgrade to sustainable comfort and start saving on energy bills.

FAQs

Can a Heat Pump Work with My Existing Underfloor Heating System?

Yes, heat pumps integrate well with underfloor heating due to their low-temperature operation, enhancing efficiency in UK homes without major changes.

What Maintenance Does a Heat Pump Require Compared to a Gas Boiler?

Heat pumps need annual servicing by a qualified engineer, focusing on filters and refrigerant levels, typically costing £100-£200—less frequent than boiler checks but essential for warranty.

How Does a Heat Pump Affect My Home’s Resale Value in the UK?

Installing a heat pump can boost resale value by 3-5% through improved EPC ratings and appeal to eco-buyers, especially in green-focused markets like South England.

Are There Tax Benefits for Landlords Installing Heat Pumps in Rental Properties?

Landlords can claim capital allowances on heat pump costs as business expenses, plus VAT relief, making it tax-efficient for buy-to-let portfolios in Wales or London.

What Happens If My Heat Pump Breaks Down in Winter?

Most heat pumps come with 5-10 year warranties, and installers like EE Renewables provide rapid response services; backup electric heaters ensure minimal downtime in cold UK weather.

Final Thoughts

Switching to a heat pump represents a forward-thinking investment in renewable technology, balancing initial outlays with enduring efficiency gains and environmental impact reductions for UK properties. By weighing tailored options and incentives, you can achieve a comfortable, cost-effective heating future.