Heat Pumps vs Gas Boilers: An Expert Guide

With the UK government’s ambitious plan to reach net zero carbon emissions by 2050, our home heating systems must be relooked. There has been a remarkable shift toward eco-savvy heating systems in recent years.

Older boilers, like oil boilers, rely on fossil fuels and release way too much bad stuff into our environment. Hence, their low-efficiency ratings and why they’re being phased out by 2035.

But even the gas boiler has its downsides, and UK energy warriors are kicking these to the curb – for new builds – from 2025.

This is where green alternatives, like heat pumps or electric boilers, come in. Heat pumps are the most carbon-friendly heating system around, with a whopping 300-400% energy efficiency rating!

But how do they compare to a gas boiler?

In this article, Eco Happy will explore the differences between these two heating systems.

Understanding Heat Pumps And Gas Boilers

Let’s take a quick look at how heat pumps and gas boilers work.

Understanding heat pumps

• A heat pump is a heating device used to heat and cool buildings.
• It transfers heat from one area (e.g. outside air) to another (e.g. inside) using a compressor and fan-like structure or gas refrigerant.
• A heat pump moves heat rather than generating it.

By moving heat rather than generating it, heat pumps reduce energy consumption and lower energy bills. They’re often used in domestic and commercial properties and can be integrated with renewable energy technology (e.g. solar panels).

To find out more details on the power of heat pumps, have your questions answered in our “Do heat pumps work in cold weather?” guide.

Types of heat pumps

You get two main types of heat pumps:

1. Air source heat pump (ASHP)

• This heat pump system extracts heat from outside air and transfers it inside. They’re used to heat and cool properties and can operate in low temperatures.
• They’re suitable for moderate-temperate climates.
• However, they can only provide warmth/cooling via central heating and do not provide sufficient hot water.
• Their energy efficiency is varied as it depends on the external air temperature. On average, heat pumps have a Coefficient of Performance (CoP) rating of 3.0 – a traditional heating system has a 1.0 CoP metric.
• Air source heat pumps are easier to install and just require an outside unit (similar to an air conditioner).
• Air source heat pump installation for two- to three-bedroomed houses costs between £8,000 and £18,000.

2. Ground source heat pump (GSHP)

• Also known as geothermal heat pumps,these systems use the consistent temperature of the ground for heating and cooling purposes.
• They provide warmth through underfloor heating systems and radiators and are hot water champions.
• GSHPs are more energy-efficient when compared to air source heat pumps as they use the constant temperature of the ground.
• Ground source heat pumps are particularly favoured in extreme weather countries.
• Installing ground source heat pumps is a bit trickier as technicians need to dig up the ground to lay a loop system – this also means that repairs are more expensive, too!
• Installation is pricier than air source heat pumps, ranging between £17,000 and £45,000.

With UK renewable heat incentive grants available, such as the Boiler Upgrade Scheme or ECO4, you can receive a heat pump grant of up to £7,500 towards your heat pump installation cost – for qualifying homes.

Understanding gas boilers

Gas boilers are common heating systems installed in the UK.

They use natural gas, which is connected to the gas network via pipes. These pipes feed gas to the boiler to power our homes with warmth and hot water. The great thing about a gas boiler is that it provides consistent hot water – no matter the weather. However, it releases mega carbon emissions and will be phased out by 2035 – making them not so eco-friendly.

(Here’s the government’s boiler stance if you don’t believe us).

Luckily, homeowners who have a gas boiler can continue using it. However, when the time comes for a replacement, you’ll have to shift away from this fossil fuel-sucking machine, as per regulations.

You get different gas boiler models:

1. Combi boiler – a compact central heating and efficient boiler system in one unit.
2. System boiler – requires a separate storage tank to store hot water and is less space-savvy than combis.
3. Conventional (regular) boiler – the bulkiest model out of the three, needing a separate water tank and hot water cylinder.

Each of these boiler types brings their own benefits and functionality to the table. For example:

• Combi boilers are the best boilers for 3-bedroom homes with 1 – 2 bathrooms.
• Regular boilers are ideal for larger properties with 3+ bathrooms.
• System boilers offer a happy medium between the two.

Head-To-Head: Heat Pumps vs Gas Boilers

Now on to the part you came here for.

We’re laying down the facts so you can make a more informed decision regarding your home heating. We’re going to dive into the differences, installation costs, running costs – and more!

Let’s compare the two in terms of:

Initial installation costs

• Heat pumps are generally expensive to install when compared to gas boilers.
  • Air source heat pump = £8,000 – £18,000
  • Ground source heat pump = £17,000 – £45,000
• Gas boiler systems vary, depending on the model type you choose. However, they are far cheaper overall than heat pumps.
  • Combi boiler = £700 – £2,500
  • System boiler = £1,500 – £4,500
  • Regular boiler = £1,700 – £2,200

Top tip: Take advantage of UK Government-backed heating schemes to offset installation costs.

Efficiency

According to 2022 statistics, UK greenhouse gas emissions resulted in over 410 million tonnes of carbon dioxide equivalent (MtCO2e). This showed a 2.2% reduction when compared to the previous year and a whopping 48.7% reduction over three decades – thank you renewable energy!

• Heat pumps are fantastic low-carbon heating solutions. They are considered a renewable source as they transfer heat instead of generating it. A heat pump is 300-400% energy efficient, meaning it generates 3 to 4 times the amount of heat per single unit of energy.
• Modern gas boilers have an “A” Energy Performance Certificate (EPC) rating due to their 90% efficiency. They produce 90p of heat for every £1 spent.

Running costs

In 2023, electricity was charged at 27 p per kWh with an annual Energy Price Cap (EPC) of £1,834 for typical households.

Ofgem, the UK’s energy regulator, announced the new price cap coming into effect from January to March 2024, when it will increase to £1,928 per year.

Huh? What does this mean?

It means the cost for various energy sources is as follows:

• Electricity = 28,62 per kWh (with a 53.35p daily standing charge)
• Gas = 7,42 per kWh (with a 29.60p daily standing charge)

Ofgem also stated that the annual energy consumption for average UK households is 2,700 kWh of electricity and 11,500 kWh of gas. With this in mind, let’s do a quick running costs comparison below.

• Air source heat pump:
  • Annual heat demand = 9,653 kWh
  • Energy efficiency = 300%
  • Annual energy use = 3,218 kWh
  • Average electricity energy price = 27p/kWh
  • Annual heating costs = £870
• Gas boiler:
  • Annual heat demand = 9,653 kWh
  • Energy efficiency = 82.5%
  • Annual energy use = 11,700 kWh
  • Average gas energy price = 7p/kWh
  • Annual heating costs = £820

This example shows that gas boilers are cheaper to run per kWh as they rely on natural gas. Natural gas is cheaper than electricity as per the above Ofgem price points.

But, as you can see, heat pumps’ annual energy usage is a third less than gas boilers.

Remember those 300-400% efficient ratings?

This reduces your reliance on the gas grid, slashes energy wastage, and allows you to kiss daily gas standing charges goodbye! Also, when connected to solar power, heat pump running costs are further reduced.

Top tip: Heat pump technicians must provide homeowners with a Microgeneration Product Standard Certificate (MCP) which is a document that lays out your potential running costs before installation.

Space requirements

The space you need for a heat pump depends on which system you install (ASHP or GSHP).

Air source pumps require less space as they only need an external unit installed.

A ground source heat pump takes up more space, as loop systems need to be installed underneath the ground. This can be slightly disruptive for homeowners while technicians dig up your garden.

Gas boilers also have varying size requirements, depending on the boiler model you use (e.g. combi, system, or regular). Combi gas boilers are the sleekest model while conventional boilers are the bulkiest.

Ease of use

• Heat pumps offer user-friendly controls and smart functionality. They are easy for homeowners to operate and are less likely to break down when compared to gas boilers. Heat pumps can also effortlessly integrate with solar power, making them a versatile and sustainable option.
• A gas boiler is a tried and tested system that most homeowners are already familiar with. Their systems are simple and easy to navigate.

Energy efficiency

• Heat pumps have a 300-400% energy efficiency rating, using three times less fuel to generate heat.
• Gas boilers are 90% energy efficient, but their “true” energy output is around 82%.

5 Alternative Heating Systems

We’re quickly going to touch on five alternate heating solutions in this section:

1. Solar systems: Solar panels absorb sunlight to generate power. The UV rays are converted into Alternating Current (AC), which is used to power appliances within our homes. Solar units are easily connected to heat pumps and most gas boilers.
2. Biomass boilers: Biomass is a renewable energy source where wood is burnt to generate power. However, these are large systems that require a lot of space.
3. Hybrid heating systems: This technology is a combination of renewable energy (e.g. heat pump) and boilers (e.g. gas or electric). Standard boilers serve as a backup energy source, should air/ground heat transfer become limited.
4. Electric boilers: This heating system is powered by electricity, which can be generated from renewable sources (e.g. wind turbines). These are reliable boilers but keep in mind that electricity prices are higher than gas, meaning they can be more expensive to run. Make sure to read our guide on the best electric combi boilers to learn more.
5. Hydrogen boilers: These future-ready boilers burn a hydrogen-natural gas (20:80 ratio) blend to power our homes. It’s a promising technology but currently has limited availability.

Want to read more about green boilers? Of course, you do!

Importance of Low-Carbon Heating Systems

As we mentioned, the Boiler Ban UK 2035 means the government wants to phase out less efficient boilers by 2035. But certain boiler ban installations in new builds will already start as early as 2025 to align with the country’s Net Zero Strategy.

Basically, this encourages homeowners to switch over to more sustainable heating solutions.

Environmental impact of traditional heating systems

For decades, fossil fuel systems have been the backbone of heating and hot water. Unfortunately, this convenient warmth comes wrapped in a nasty layer of environmental damage. Burning fuels, like oil, gas, and coal, release major emissions into the atmosphere. This is accelerating the global warming crisis.

Lowering our reliance on fossil fuels is a surefire way to preserve planet Earth for future generations. Transitioning to renewable energy sources, like solar panels, or a low-carbon system, like heat pumps, drastically reduces air pollution. (Bonus: You’ll save on your energy bills too!)

Benefits of low-carbon systems

To recap, switching to eco-friendly heating has many benefits, such as:

• Lower carbon emissions and greenhouse gases (i.e. less air pollution)
• Sustainable energy source
• Reduces dependency on fossil fuels
• Energy efficient
• Energy price stability (i.e. lower energy bills)
• Aligns with UK Net Zero Strategy
• Helps you save our planet

FAQs

What houses are suitable for heat pumps?

Another advantage of heat pumps is that they’re compatible with almost every type of home. Gas boilers, on the other hand, need a reliable gas connection, making them a more limited option.

Why is my electric bill so high with an air source heat pump?

The reason for this is that electricity rates (28,62 per kWh) are higher than gas (7,42 per kWh), as per Ofgem’s price cap. However, you’ll probably notice that your gas bill has drastically reduced!

Conclusion

And there we have it – a complete heat pump vs gas boiler rundown.

As the humble gas boiler is slowly phased out, we look towards the future with a newfound sense of responsibility for sustainability as we welcome the renewable energy era.

It’s exciting to see how effective heat pumps are, being the most carbon-friendly and eco-friendly heating system around. These nifty systems provide warmth by transferring heat instead of generating it.

While gas boilers are great, their time is running thin and the environmental impact they have is not cutting it anymore. When considering making the switch to sustainable energy, weigh up your options before making a final decision. Whether you opt for air- or ground-source heat pumps, chat with the Eco Happy team today.