(Updated 6th September 2024)
To reduce carbon emissions from home heating, we need to shift away from polluting fossil fuel boilers towards clean, low-carbon technologies such as air and ground source heat pumps. Heat pumps may seem like relatively novel technologies to the British market, but they have been used for decades in Scandinavia. With the expertise and help of the Climate Change Transformation Board's Decarbonisation Advisor, Dave Sowden and the Manx Utilities team behind the Air Source Heat Pump (ASHP) Trial here on the Isle of Man, we've compiled a list of the most frequently asked questions we receive:
How much does an ASHP cost?
In the Isle of Man, on the Manx Utilities scheme, ASHP installations have cost between £13-16,000 for an average 3 – 4 bedroom property. These costs have risen recently due to added labour & kit costs. The MU cost includes a 10-year interest-free loan (5% deposit), a 10-year service package and an extended 7-year manufacturer warranty.
Manx Utilities provides a Comfy Heat tariff for Electric heating and Heat pumps, with reduced unit rates between the hours of 00.00 to 06.00 and 14.00 to 16.00 GMT. Utilising the heating and domestic appliances on setback times during these periods can make savings of around 25%.
Working with industry, the UK government aims to reduce the costs of installing a heat pump by at least 25% to 50% by 2025 and towards parity with boilers by 2030.
Why should I switch?
A heat pump installation may have a larger financial outlay. A heat pump installation is also methodical as it requires a complete heat loss assessment of the property, this is to ensure the ASHP is sized correctly and highlight any radiators that may require upgrading.
A gas or oil boiler can easily mask the fact that it's not operating efficiently (with the consequence of higher bills, but still able to provide sufficient heat due to its ability to operate – albeit very inefficiently – at high temperatures),
Operational costs are also lower for heat pumps, with savings between £551 - £789 annually using Isle of Man energy prices. Greenhouse gas emissions can be up to 82% less compared to gas and 88% less compared to oil as found in new research.
How efficient are they?
An air source heat pump can transfer 300% - 400% more energy than it consumes, meaning 1kW of electrical energy will convert to between 3-4kW of heat energy. Which is more efficient compared to a comparatively modern condensing gas boiler, which operates at a typical efficiency of around 84%.
To get the best out of your heating system, as a customer you should receive a clear explanation to understand the differences of a heat pump system and be shown how to use the controls. These controls allow the homeowner to monitor usage, and efficiency and enable the system to be controlled using smart apps.
They perform best when they heat homes gradually with gentle fluctuations in temperature. It is often more efficient for a heat pump, allowing its control system to optimise its performance, rather than the conventional habit of switching a boiler off during times of the day when the property is unoccupied. Homeowners of ASHP’s will testify that maintaining a regular temperature within the home provides a more comfortable heat.
Will I save money on fuel bills?
A properly designed air source heat pump installation is a much more efficient heating system and can save you money on energy bills straight away. Relative to current gas and electricity prices, a properly specified and correctly installed heat pump can save customers £551 - £789 annually on fuel bills.
Over its lifetime, you can save £9,246 compared to a gas boiler and £144 compared to an oil boiler as prices return to long-term trends in 2035 and heat pump efficiencies increase. Some customers of the MU trial have seen bigger savings compared to oil. View the Isle of Man Heat Pump study.
Are they reliable? They are still new to the market and haven’t been tried and tested.
Heat pumps have been used for decades and use the same core technology as air conditioning. A wide range of them are available today and the technology is constantly improving.
Heat pumps have grown in popularity in Scandinavia since the 1980s [1] and the rollout across Europe has rapidly accelerated in the last few years. The UK is following suit with heat pumps right at the heart of a government policy to decarbonise heating that has an ambition to end the sale of gas boilers altogether by 2035 [2]. UK research has found they are suitable for many types of homes, which has been confirmed by the ongoing trial by Manx Utilities that’s now in its third phase. In both phases one and Two, a sample of new heat pump users surveyed presented an average of 91% satisfaction rate with users stating they would recommend the system to others.
They have also been used in social housing in Ramsey since 2018 which has had a positive impact on tenant’s bills.
We are delighted with the performance of the ASHP which exceeded our expectations – the running costs of an ASHP are significantly less than a gas boiler. The cost of installation is likely to be prohibitive to most and this trial Scheme run by the MUA greatly assists in spreading the cost of the capital spent. Although the ASHP can be heard when sitting in the garden, the overall noise from the ASHP is no louder than the previous gas boiler when operating. We would only move home into another house if it had an ASHP. - Manx Utilities ASHP Trial customer
How long do they last?
For a properly and professionally maintained heat pump, the average lifespan of an air source heat pump is 15-20 years for modern technology [3].
Will they work in a Manx stone cottage?
It depends on your current heating system and the age and fabric of the building. You should consult a reputable installer and ask for their advice. In some cases, particularly if you have an oil boiler, it may be preferable to use a biofuel in your existing boiler instead. However, the Isle of Man Government is still working on biofuel availability for the Island. You could also consider biomass.
Very satisfied, we live in an 1830s Manx Stone Cottage and the outcome has been beyond our expectations, we do highly recommend this to everyone! - Manx Utilities ASHP Trial Customer
Does coastal air cause corrosion?
Manufacturers of ASHP’s have done a lot in recent years on anti-corrosion coatings to address exactly this problem. Reputable manufacturers supply products fit for coastal environments, you should check with the installer before they obtain a heat pump to make sure this is considered.
How much maintenance do they require?
They need less maintenance than gas, oil, or LPG systems because they don't use flammable fuels, so there is no risk of carbon monoxide accumulation. Seek your installer’s advice and adhere to the manufacturer’s warranty criteria requirements on servicing. It is recommended to have a professional service annually as they do require an occasional pressure check, cleaning of the outdoor unit's fins for debris and service on the associated unvented water cylinder.
Will it provide my home with enough heat?
Your installer must carry out a room-by-room heat loss survey to ensure that your ASHP is sized correctly to heat your home adequately. This also includes the sizing of the properties of heat emitters such as radiators and UFH systems. A correctly sized system will provide adequate heat which is comfortably distributed throughout the day.
Related blogs and pages;
Moving to clean heating systems
Low carbon heating options
8 common myths about air source heat pumps explored
Why hydrogen is unlikely for home heating