Around 85% of UK homes use a traditional boiler to provide hot water and heat their homes. However, with energy bills on the up and the effects of climate change becoming more evident, many home and business owners are looking at alternatives to traditional heating systems. If you have an LPG, gas or oil boiler, it may be worth considering moving to an air source heat pump.
Air source heat pumps are an energy-efficient alternative to boilers and are cheaper to run in most cases. They don’t burn fossil fuels and so will reduce your home’s carbon emissions. Like a boiler, an air source heat pump can supply hot water and work with an existing central heating system.
No wonder a record number of property owners – 36,799, to be precise – decided to install heat pumps in 2023 (source: MCS). If you are looking to install a heat pump yourself and want to find out more about how it can outperform your gas boiler, then read on.
Cinergi is a trusted expert offering all types of domestic heating services, including air source heat pumps. You can rely on us to undertake a detailed assessment of your property and offer independent energy advice. To book a callback from one of our friendly team, please fill out our contact form.
Can an air source heat pump replace my boiler?
Yes, an air source heat pump can replace a natural gas, LPG, or oil boiler in an existing property. This remarkable technology works by transferring heat energy from the outside air into the home.
A heat pump is compatible with radiators and underfloor heating and provides a reliable source of hot water, which it stores in a hot water cylinder. Basically, anything your boiler can do, an air pump does, but, in most cases, more efficiently!
For more information on how heat pumps operate, please visit our FAQs page or contact us today.
Do heat pumps work with boilers?
Yes, an air source heat pump can work with an oil, LPG, conventional, or combi boiler to create a hybrid system. It depends on the property’s heat requirement, and in some instances, it is preferable.
In this setup, the heat pump provides heating most of the time, while the boiler kicks in during very cold weather or when a higher temperature of water is needed. This combination allows for greater flexibility and energy savings.
The first stage in any good air source heat pump design process is to carry out a heat loss calculation by assessing the building fabric and measuring walls, windows, etc. Depending on the result, a reliable heat pump installer like Cinergi can advise you on what is best for your property.
If your property’s heat loss comes in at 16kW or less, then a heat pump alone is sufficient. If your home’s heat loss is greater than 16kW (and you don’t have 3-phase electricity), then it may be that a hybrid heat pump is the best option.
Benefits of switching to air source heat pumps
Here’s a look at why making the switch to an air source heat pump could be a smart move for your home:
1. Lower heating bills
Heat pumps operate with impressive efficiency. They often deliver more energy in the form of heat than they consume in electricity. Depending on the model, every unit of electricity used can produce up to three or four units of heat.
This high efficiency translates into significant savings on heating bills, especially as energy costs continue to rise. Over time, these savings can outweigh the initial investment in the system, providing long-term financial benefits.
2. Reduced carbon emissions
A heat pump can dramatically reduce a home’s carbon footprint. Unlike gas or oil boilers that rely on fossil fuels, air source heat pumps use electricity to extract heat from the outside air. When paired with renewable energy sources like solar panels, carbon emissions can be reduced even further.
3. Energy efficiency
An air source heat pump harnesses the thermal energy in the air, even in colder climates. They work by transferring heat from the outdoor air into your home, meaning that they don’t generate heat but rather move it. This process is much more energy-efficient than traditional heating methods, which burn fuel to create heat.
4. Versatility and compatibility
You might be concerned about whether an air source heat pump can be integrated with your existing heating system. The good news is that they are quite versatile and can often be adapted to work with your existing radiators and pipework.
In some cases, upgrading to larger radiators or underfloor heating may improve the performance of the system, but overall, the transition is relatively straightforward. ASHPs can also provide cooling during warmer months, offering a year-round climate control solution in one system.
5. Future-proofing your home
As we move towards the government’s net zero targets, there is a goal to reduce new gas boiler installations by 80% by 2035. By switching to an air source heat pump, you’re taking proactive steps to future-proof your home. Installing an ASHP can also increase the marketability of your home as energy efficiency and sustainability become a higher priority for home buyers.
7. Low maintenance and long lifespan
Air source heat pumps require relatively little maintenance compared to traditional boilers. Regular servicing, typically once a year, is usually enough to ensure that the system runs efficiently. With proper care, a heat pump system can last 15-20 years or more, which is longer than the average lifespan of a gas or oil boiler. This durability adds to the long-term value and cost savings of the investment.
Can air source heat pumps heat water?
Yes, in most cases, an air source heat pump is sufficient for all of your hot water and central heating requirements.
It is a common misconception that we need piping hot water in our homes; in fact, we very rarely use water hotter than 45°C.
At Cinergi, we typically commission our air pump heating systems to provide domestic hot water between 45-50°C. Some modern heat pumps can comfortably achieve flow temperatures of 80°C. In fact, you really won’t notice the difference between hot water generated by a heat pump and that of a boiler!
Is an air source heat pump cheaper to run than a gas boiler?
Air and ground source heat pumps can work without a gas supply but need electrical energy to run. To work out if a heat pump is more cost-effective, it comes down to the efficiencies and unit costs of both fuels:
- a boiler creates approximately 0.9kWh of heat for every kWh (kilowatt hour) of gas burned
- a heat pump creates around 3.6kWh of heat from every kWh of electricity
This means that heat pumps use a quarter of the energy of a gas boiler.
However, we all know that electricity is more expensive than gas. How much an air pump can save you depends on your gas and electricity costs per kWh.
Here’s an example based on current average gas and electricity costs:
- Gas cost = 10.3p/kWh
- Electricity cost = is 34p/kWhA boiler uses four times as much gas to generate the same amount of heat as a pump, so:
- 10.3p x 4 = 41.2p/kWh
So, in this case, a heat pump is around 18% more cost-effective.
For more guidance on the potential cost saving of installing heat pumps, visit The Energy Saving Trust’s website. As of October 2024, they calculate the potential savings of switching from an old boiler to an air source heat pump as follows:
- from an old gas boiler – £290 per year
- from an old LPG boiler – £650 per year
- from an old oil boiler – £280 per year
What to consider before replacing a boiler with an air source heat pump
Switching from a conventional heating system like a gas boiler to an air source heat pump is an excellent option for reducing heating bills and cutting carbon emissions. However, before making the leap, there are several factors to consider.
How much does a heat pump cost?
Air source heat pump installation costs to an existing property can be higher than installing a new, traditional boiler, particularly if you need additional upgrades, such as a new hot water cylinder or modifications to your existing radiators.
The cost also depends on the size of your property, how well it is insulated, and your energy needs. If you have cavity wall insulation and double glazing, you’re likely to benefit more from the energy savings over time, even with current energy prices.
Expect to pay in the region of £4,000-£6,000 (after the BUS voucher has been deducted) for a modern three-bedroom, semi-detached property.
Contact Cinergi for a personalised quote based on your energy needs.
Household energy consumption
Air source heat pumps work more efficiently at lower temperatures than conventional heating systems. If your home is well-insulated, the heat pump unit will use less energy, meaning lower heating bills.
However, homes with poor insulation might struggle to achieve the same savings. Improving insulation, such as upgrading cavity wall insulation, can make heat pumps more effective.
Installation process
The installation of an air source heat pump is more involved than replacing a gas boiler.
The process involves installing both an outdoor and an indoor unit. The outdoor unit is usually placed by an external wall on the ground, where it can efficiently absorb heat from the air. This unit needs adequate space and ventilation to function effectively.
The inside unit is modest, around 100cm high by 30-50cm deep. If you don’t already have one, you may need a new hot water cylinder and adjustments to your existing pipework. Homes with a gravity-fed system may need upgrades to handle the lower water pressure and temperature typical of heat pumps.
Additionally, your radiators need to be checked and potentially replaced to ensure they are compatible with the heat pump’s lower temperature output and to maximise efficiency.
Government grants
Fortunately, the Boiler Upgrade Scheme (BUS) provides grants of £7,500 for air and ground-source heat pumps and £5,000 for biomass boilers.
Initially launched in 2022, the scheme has been extended to March 2028, with additional funding allocated to meet growing demand.
To be eligible for the grant, you must own a property in England or Wales. The property must also have a valid Energy Performance Certificate (EPC) with no outstanding recommendations for loft or cavity wall insulation at the time of application.
See GOV.UK and Ofgem for further details.
Conclusion: should I ditch the boiler?
The short answer is, if you can, YES, you should replace your boiler with an energy-efficient system like an air-source heat pump. It can improve your home’s energy efficiency, reduce your carbon footprint, and save you money. What’s more, an air-source heat pump requires little maintenance, typically every two years, and has a life expectancy of 20-30 years.
There is a financial outlay at the start, but you may be eligible for the Boiler Upgrade Scheme (see above). If not, your air-source heat pump will still pay for itself over time, and you can begin to enjoy lower running costs straight away.
It’s also worth considering that if you can ditch the boiler and no longer require gas, you can notify your supplier and save on paying the standing charge on your gas supply.
Contact the air source heat pump experts at Cinergi
At Cinergi, our team of highly accredited engineers has 40 years of experience in domestic and commercial energy. Our customers enjoy a high level of service and recommend us for our quality workmanship and trustworthiness. In addition to traditional gas boiler services, we can offer a range of low-carbon heating systems, such as biomass boilers and ground source heat pumps.
We are trusted local installers of air source heat pumps in Hampshire and all along the South Coast. We are not tied to any one supplier, so we can give you impartial, honest advice on a wide range of heat pump systems depending on your requirements.
To ask questions or to arrange a call back, please contact us.
Frequently asked questions about replacing a boiler with a heat pump
The cost of replacing a boiler with a heat pump can vary depending on the size of your property, its insulation, and your energy requirements.
Expect to pay in the region of £6,000 to £8,000 (depending on the heat requirement of your property) for air-source heat pumps. A ground-source heat pump is more expensive due to the need for ground excavation, starting at around £14,000.
While upfront costs are higher than replacing a traditional boiler, heat pumps offer long-term savings through lower energy bills and reduced carbon emissions. Government incentives like the Boiler Upgrade Scheme may also help reduce the overall expense.
Absolutely, and in fact, this is where the largest cost savings can be made. According to The Energy Saving Trust’s October 2024 figures, switching from old electric storage heaters to an air-source heat pump can save a whopping £1,200 per year.
If you only need an air pump to heat your home, a water tank is not required. However, a heat pump is usually installed to provide heating and hot water.
Unlike a boiler, a heat pump doesn’t heat water instantaneously, so the water needs to be stored in a domestic hot water cylinder. A heat pump-compatible cylinder is required, which can be installed in airing cupboards and lofts. It’s not usually possible to use an existing water cylinder.
Yes, provided they’re designed correctly! If you scour the internet, you will find numerous stories about heat pumps not working. These are nearly all due to outdated technology and poor design and installation. Therefore, it is vital to choose your installer carefully – this is far more important than the heat pump itself!
A conscientious heat pump installer, like Cinergi, will carry out accurate heat loss calculations before recommending the appropriate size of pump – not to state the obvious, but if your heat pump is not big enough, your house will be cold!
A trustworthy installer will also ensure that the emitters in the property’s radiators or underfloor heating are sized correctly to accommodate the lower flow temperature heat pumps generate. An upgrade to your radiators or underfloor heating may be required.
As with all home maintenance, diligence, accuracy, and good design are essential to ensuring your air source heat pump works to maximum efficiency. At Cinergi, we are lucky enough to receive glowing reviews from our happy customers, a testament to how well heat pumps can work when designed and installed by a true expert.
An air source heat pump comprises of an external unit, which is about the same size as a standard air conditioning unit. They range in size from 80 to 140 cm (31 to 55 inches) wide, 60 to 110 cm (24 to 43 inches) tall, and 30 to 40 cm (12 to 16 inches) deep. Unless you opt for a hybrid system, there is no requirement for a boiler, but a hot water cylinder is necessary to store the hot water that a heat pump supplies.
