Heat pump vs gas boiler: home heating comparison

Choosing how to heat your home is a significant decision, balancing upfront costs, ongoing expenses, efficiency, and environmental impact. Heat pumps extract heat from the environment to warm a home, while gas boilers generate heat by burning natural gas. This comparison focuses on the real-world running costs and efficiency of these systems.

Understanding your home heating options

The drive for efficient home heating

The push for more efficient home heating is driven by rising energy costs and environmental concerns. Homeowners are increasingly looking for systems that can reduce their carbon footprint while keeping bills manageable. This often means considering alternatives to traditional gas boilers.

What is a heat pump?

A heat pump is an electric device that extracts heat from a source - typically the air, but sometimes the ground or water - and transfers it into your home. Even on cold days, there is enough heat in the outside air for a heat pump to work effectively. They do not generate heat by burning fuel; instead, they move existing heat, making them highly efficient.

What is a gas boiler?

A gas boiler generates heat by burning natural gas. This heat is then used to warm water, which circulates through radiators and provides hot water for your taps. Gas boilers have been the dominant heating system in the UK for decades due to the widespread availability of natural gas.

How heat pumps and gas boilers work

The mechanics of a heat pump

Heat pumps operate on a principle similar to a refrigerator, but in reverse. They use a refrigerant to absorb heat from the outside air, compress it to increase its temperature, and then release this heat into your home's heating system and hot water tank. For every unit of electricity consumed, a heat pump can produce at least three units of heat, a measure known as its Coefficient of Performance (COP).

The mechanics of a gas boiler

A gas boiler ignites natural gas in a combustion chamber, heating water that is then pumped around your home. Modern condensing gas boilers capture heat from the exhaust gases, which would otherwise be wasted, to pre-heat the returning water, improving efficiency.

Efficiency: heat pump vs gas boiler

Heat pump efficiency (COP)

Air source heat pumps can achieve efficiencies of 300% or more, meaning they produce at least 3 kWh of heat for every 1 kWh of electricity used. This efficiency is often measured by the Seasonal Coefficient of Performance (SCOP), which accounts for varying outdoor temperatures and operating conditions throughout the year. Most modern systems can achieve a SCOP of 3.0 to 4.5 when properly designed and installed.

Gas boiler efficiency

Modern condensing gas boilers can achieve efficiencies of 90% or higher. This means that for every unit of gas consumed, 90-95% of the energy is converted into usable heat, with the remainder lost through the flue. While this is a high percentage, it is important to remember that they convert fuel into heat, rather than moving existing heat like a heat pump.

Running costs: heat pump vs gas boiler

Impact of electricity and gas prices

The running costs for both heat pumps and gas boilers are heavily influenced by the fluctuating unit prices of electricity and gas. Electricity is generally more expensive per unit than gas. However, a heat pump's high efficiency (SCOP) means it uses significantly less energy overall to produce the same amount of heat. The average UK home uses around 2,500 kWh of electricity per year and 9,500 kWh of gas per year.

Optimising running costs with smart tariffs

Regardless of your heating system choice, optimising running costs is crucial. Fuse Energy provides a data-backed approach to this, focusing on real-world efficiency. Our app helps customers monitor and optimise energy usage for both electricity (heat pumps) and gas (boilers), aligning with the vision of empowering you with control. Smart tariffs can play a significant role, especially for heat pump owners, by rewarding off-peak electricity usage when prices are lower.

Installation costs and government grants

Upfront costs for heat pumps

Typical air source heat pump installation costs in the UK range from £7,000 to £15,000 before grants. This cost can vary depending on the size of your home, the specific system chosen, and any additional work required, such as upgrading radiators or insulation.

Boiler Upgrade Scheme (BUS)

The Boiler Upgrade Scheme (BUS) offers significant grants to reduce the upfront cost of heat pump installations in England and Wales. The standard grant is £7,500 for air source and ground source heat pumps. For homes currently using heating oil, an uplifted grant of £9,000 is available. To claim the BUS grant, installations must be carried out by an MCS-certified installer. The installer applies for the grant on the homeowner's behalf, and the grant value is deducted from the installation quote.

Upfront costs for gas boilers

The upfront cost of installing a new gas boiler is generally lower than that of a heat pump. While costs vary, they typically range from £1,500 to £4,000, depending on the boiler type and complexity of the installation. Fuse Energy installs the Vaillant ecoTEC Plus gas boiler, known for its efficiency and reliability.

Suitability for your home

Insulation and property type

Heat pumps perform best in well-insulated homes, as they deliver heat at a lower, more consistent temperature than gas boilers. Older, less insulated properties may require insulation upgrades to maximise a heat pump's efficiency and ensure comfort.

Radiator compatibility and sizing

Heat pumps often work optimally with larger radiators or underfloor heating systems, which can effectively distribute the lower flow temperature heat. Existing radiator systems may need to be upgraded to accommodate a heat pump, adding to the overall installation cost.

Space requirements

Air source heat pumps require an outdoor unit, similar in size to an air conditioning unit, which needs adequate space and airflow. Gas boilers are typically more compact and can be installed indoors, often within a kitchen cupboard or utility room.

Environmental impact and carbon footprint

Emissions from heat pumps

Heat pumps have a significantly lower carbon footprint than gas boilers because they use electricity to move heat rather than burning fossil fuels. As the UK's electricity grid decarbonises with more renewable energy sources, the environmental benefits of heat pumps will continue to grow.

Emissions from gas boilers

Gas boilers contribute to carbon emissions by burning natural gas, a fossil fuel. While modern condensing boilers are efficient, they still release greenhouse gases into the atmosphere. Heating homes accounted for 18% of all UK greenhouse gas emissions in 2021.

Making your informed decision

Pros and cons of heat pumps

Pros:

• Highly energy-efficient, producing more heat than the electricity they consume.
• Lower carbon emissions, contributing to a greener home.
• Potential for significant long-term running cost savings, especially with smart tariffs.
• Eligible for government grants like the BUS.

Cons:

• Higher upfront installation costs compared to gas boilers.
• Performance can be affected by poor home insulation.
• May require upgrades to existing radiator systems.
• Electricity unit prices are generally higher than gas.

Pros and cons of gas boilers

Pros:

• Lower upfront installation costs.
• Familiar technology for most homeowners.
• Effective at heating homes quickly, even with older radiator systems.
• Compact size, requiring less installation space.

Cons:

• Higher carbon emissions due to burning fossil fuels.
• Running costs are directly tied to volatile gas prices.
• Less efficient in terms of energy input vs heat output compared to heat pumps.
• Not eligible for BUS grants.

Fuse Energy's role in your heating journey

Fuse Energy positions itself as an unbiased expert in energy consumption and cost optimisation for any heating system. We empower homeowners to make the best choice for their specific needs and then manage that choice effectively. While Fuse offers Vaillant ecoTEC Plus gas boiler installations, we do not install heat pumps. Our focus is on providing transparent information and tools, such as our app, to help you monitor and optimise your energy usage, regardless of your chosen heating solution.