If you're weighing up the options for your heating system, you’ve likely come across two main choices: the familiar gas boiler and the increasingly popular heat pump.

With rising energy costs, environmental concerns, and new government incentives, now’s the perfect time to make an informed decision. In this article, we’ll break down the key differences, helping you decide which option makes the most sense for your home in 2025.

Key differences between heat pumps vs boilers

When considering a new heating system, it’s important to understand the fundamental differences between heat pumps and gas boilers. From how they work to their long-term costs and environmental impacts, the choice may not be as simple as it seems. Let’s take a closer look at how these two systems compare across several key features.

Learn more about heat pumps.

Upfront Costs

Cost is a major factor when choosing between a gas boiler and a heat pump. While boilers have a lower upfront price, heat pumps come with higher initial costs—but government grants and collective buying schemes can help make them more affordable.

The Boiler Upgrade Scheme offers a £7,500 grant, reducing the typical heat pump cost to around £7,000. Additionally, initiatives like Switch Together leverage group buying to bring heat pump costs down even further, with some homeowners paying as little as £2,500–£3,000 after grants.

By taking advantage of grants and collective buying, the upfront cost of a heat pump becomes much more competitive—making it a viable long-term investment for many homeowners.

Energy Efficiency

Energy efficiency is one of the biggest draws of heat pumps. With their ability to extract heat from the air, they can provide much higher efficiency compared to gas boilers. In this section, we’ll compare the energy efficiency of both systems and what it means for your energy bills.

Running Costs

The ongoing running costs of your heating system can have a big impact on your household budget over time. Heat pumps are typically more energy-efficient than gas boilers, but they come with their own costs, including potential maintenance. In this section, we’ll break down the average annual running costs for each system.

Heat pumps can compete with gas boilers – and in some cases beat it, especially if:

• You’re switching from an old G-rated boiler

• You use a dedicated heat pump electricity tariff

• You have solar panels

Maintenance & Lifespan

Both heat pumps and gas boilers need annual servicing to ensure efficiency and safety. Gas boilers often require repairs as they age, with common issues like faulty thermocouples or pressure valves. They typically last 10–15 years, but performance can decline after a decade, leading to higher repair costs.

Heat pumps generally need less maintenance since they have fewer moving parts. Regular checks include clearing debris from the outdoor unit and monitoring antifreeze levels. With a 20–30 year lifespan, heat pumps last significantly longer than boilers, making them a durable long-term investment.

Can a Heat Pump Replace a Gas Boiler?

Yes, but with some key differences. Heat pumps can fully replace a gas boiler for both heating and hot water, but they operate in a different way. Unlike gas boilers, which provide instant hot water on demand, heat pumps heat and store hot water in a cylinder, meaning you’ll need to plan for additional space.

If your home already has a hot water tank (e.g., with a system boiler), switching to a heat pump is straightforward. For homes without one, installing a cylinder may require some adjustments, but it’s a manageable upgrade for most properties.

Carbon Emissions

Reducing your home’s carbon footprint has never been more important, and when it comes to emissions, heat pumps are the clear winner. Unlike gas boilers, which burn fossil fuels and release 2–3 tonnes of CO₂ per year, heat pumps run on electricity and produce significantly lower emissions—a number that will continue to drop as the UK grid moves toward renewable energy.

According to Carbon Brief, switching from a gas boiler to a heat pump can cut home heating emissions by up to 80%, making it one of the most effective ways to reduce your household’s environmental impact.

By choosing a heat pump, you're not just lowering your energy bills—you’re also investing in a cleaner, more sustainable future.

Carbon Emissions Impact
Heat pumps can cut your home’s carbon emissions a lot compared to gas heating:

• Average saving: Around 1.4 tonnes of CO₂ each year if you replace a modern gas boiler — roughly the same as driving 5,000 miles in an average petrol car or taking a return flight from London to New York.

• Biggest saving: Up to 2.9 tonnes a year if you replace an old, inefficient gas boiler— similar to driving over 10,000 miles or three return flights from London to Barcelona.

• Getting better over time: As the UK’s electricity supply uses more renewable energy, heat pumps will create even fewer emissions in the future — like taking more “cars off the road” without doing anything extra.

Space & Installation

The space required for installing a heat pump or gas boiler is an important consideration for many homeowners. Heat pumps require both an outdoor unit and an indoor hot water cylinder, while gas boilers are typically more compact and easier to fit into smaller spaces. We’ll compare the space requirements and installation considerations for each system in this section.

• Detached & semi-detached houses: Ideal for heat pumps – plenty of outdoor space, good access.

• Terraced homes: Still doable. Heat pumps have been fitted successfully in Victorian terraces during UK government trials (source).

• Flats: Trickier, but not impossible. Shared heat pumps or communal systems are increasingly common in new builds.

For heat pumps, you’ll also need room for a hot water cylinder. Boilers don’t need one – that’s why they’re popular in smaller homes and flats.

New Builds vs Retrofits

From 2025, new homes will no longer be allowed to install gas boilers under the Future Homes Standard. That means heat pumps will become standard in new builds.

In existing homes, installing a heat pump may require some upgrades – like radiators. But thanks to government support, and innitiatives like Switch Together, it’s much more common and achievable.

What About Electric Boilers?

Electric boilers are another option that you might be considering, particularly if your home doesn’t have access to gas. While they are compact and simple to install, electric boilers are typically more expensive to run compared to heat pumps. They work like traditional boilers (100% efficiency), which means they’re usually more expensive to run than gas boilers or heat pumps. Unlike heat pumps, they don’t benefit from the same government grants or performance efficiencies.

Final Thoughts: Which Should You Choose?

There’s no one-size-fits-all answer – but if you live in a detached, semi-detached, or well-insulated home, the numbers are stacking up for heat pumps. And with gas bills on the rise and grants still available, now’s a great time to explore your options.

Go for a heat pump if:

• You’re planning long-term.

• You want to cut your carbon footprint.

• You want to take advantage of grants before they disappear.

Stick with a boiler if:

• You need a quick, lower-cost replacement.

• You have very limited indoor or outdoor space.

• You’re likely to move soon.

Still not sure? Register to receive a personal offer from a qualified installer to see how heat-pump ready you are.