Can an air source heat pump replace a boiler?

can an air source heat pump replace a boiler
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    Around 85% of UK homes use a traditional boiler to provide hot water and heat their homes. However, with fuel prices on the up, energy bills are becoming a concern for many. If you have a natural gas boiler (or an LPG 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 do not burn fossil fuels and therefore reduce a home’s carbon emissions. Like a boiler, an air source heat pump can reliably supply hot water and work with an existing central heating system.

    An air source heat pump system could be the answer to reducing your energy bills and carbon footprint in the years to come. If you want to find out more about how a heat pump 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 call back from one of our friendly team, please fill out our contact form.

    Can an air source heat pump replace my boiler?

    An air source heat pump can replace a natural gas, LPG or oil boiler to heat water. The heated water can be used to run central heating systems, including both radiators and underfloor heating. 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 service page and FAQs page.

    Do heat pumps work with boilers?

    Yes, an air source heat pump can work with a boiler to create a hybrid system. It depends on the heat requirement of the property and in some instances, it is preferable.

    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 a hybrid system is likely your best option.

    What are the advantages of a heat pump/boiler hybrid system?

    A hybrid system will heat the property until the external temperature drops to a pre-calculated level (this may be anything between 0°C and 10°C). If the temperature drops below this, then the heat pump will shut down and the boiler will take over.

    This is clearly an advantage if you live in a cold part of the country in an older, less insulated property, for example.

    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 and 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 source heat pumps negate the need for a gas supply, but require 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 what you’re paying for gas and electricity per kWh.

    Here’s an example based on current average gas and electricity costs:

    • Gas cost = 10.3p/kWh
    • Electricity cost = is 34p/kWh
    • A boiler uses 4 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 2022, they calculate the potential savings of swapping from an old gas boiler as £395 per year.

    Conclusion: should I ditch the boiler?

    The short answer is, if you can, YES you should ditch your boiler. It will 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 over time your air source heat pump will pay for itself and you can begin to enjoy lower the benefits of lower running costs.

    If you are on the fence about replacing your gas or oil boiler, consider that the government is currently running the Boiler Upgrade Scheme (BUS) that offers a £5,000 incentive to install heat pumps. Installation costs vary, but are generally around £10,000 to £15,000, so the grant offers a significant contribution.

    It’s also worth considering that if you can ditch the boiler and no longer have any requirements for gas, then 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 have both domestic and commercial energy experience spanning 40 years. Our customers enjoy a high level of service and recommend us for our quality workmanship and trustworthiness.

    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 a wide range of heat pump systems depending on your requirements.

    To answer any further questions you may have, or to arrange a callback, please contact us.


    Can air source heat pumps replace electric storage heating?

    Absolutely, and in fact, this is where the largest cost saving can be made. According to figures from The Energy Saving Trust’s figures for October 2022, switching from old electric storage heaters to an air source heat pump can save a whopping £1,500 per year.

    What’s the difference between air source heat pumps and ground source heat pumps?

    As the name suggests, an air source heat pump uses the outside air to produce heat energy, while a ground source heat pump gathers heat energy from the earth. Ground source heat pumps require a lot more land to house the underground piping system required. Read more about ground source heat pumps here.

    Do you need a water tank with an air source heat pump?

    If you only require an air pump to heat your home, then a tank is not required. But usually, a heat pump is installed to provide heating and hot water.

    Unlike a boiler, a heat pump can’t heat water instantaneously, meaning that the water needs to be stored in a domestic hot water cylinder. We’re often asked if an existing hot water tank can be used, but the answer is sadly, no. A heat pump compatible cylinder is required, which can be installed in airing cupboards and lofts.

    Are air source heat pumps as good as gas boilers?

    Yes, providing they’re designed correctly! If you scour the internet you will find numerous horror stories about heat pumps not working – these are nearly all down to poor design and installation. Therefore, it is vital to choose your installer carefully – this is far more important than that heat pump itself!

    A conscientious heat pump installer, like Cinergi, will carry out accurate heat loss calculations before recommending the size of pump that is appropriate – not to state the obvious, but if your heat pump is not big enough then your house is going to be cold!

    A trustworthy installer will also ensure that the emitters in the property’s radiators or underfloor heating are sized correctly, to allow for the lower flow temperature heat pumps generate. It may be that an upgrade to radiators or underfloor heating is required.

    As with all home maintenance, it comes down to diligence, accuracy and good design to ensure 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 just how well heat pumps can work when designed and installed by a true expert.

    Do air source heat pumps take up more room than gas boilers?

    An air source heat pump is located outside of a property, usually on an external wall, and is similar in size and appearance to an air conditioning unit. 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.

    Picture of Dan Loveridge
    Dan Loveridge

    Dan is the managing director at Cinergi, a renewable energy company based in southern England specialising in air source heat pumps and EV charging solutions.

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