Air Source Heat Pump FAQs
Your questions about air source heat pumps answered.
What is the Boiler Upgrade Scheme (BUS) grant?
The Boiler Upgrade Scheme is a UK government grant offering £7,500 towards the cost of installing a qualifying air source heat pump. The grant is applied directly to your installation cost — you don't need to claim it yourself. Halo Heating is an MCS certified installer, meaning we can apply for the BUS grant on your behalf.
How much does an air source heat pump cost?
An air source heat pump installation typically costs between £10,000 and £18,000 before the BUS grant. After the £7,500 grant, net costs are usually between £4,000 and £12,000 depending on the size of the system, any required upgrades to your heating distribution (such as radiators), and whether a hot water cylinder is needed. We provide free, no-obligation heat pump surveys.
What is COP and why does it matter?
COP stands for Coefficient of Performance — it measures how efficiently a heat pump converts electricity into heat. A COP of 3 means the heat pump produces 3 units of heat for every 1 unit of electricity consumed. Most modern air source heat pumps achieve a seasonal COP (SCOP) of 2.5–4 under UK climate conditions, making them significantly more efficient than gas boilers in terms of energy conversion.
Do heat pumps work in cold weather?
Yes. Modern air source heat pumps are designed to operate effectively at outdoor temperatures as low as -20°C, though efficiency decreases in very cold conditions. The UK rarely experiences temperatures where a heat pump cannot operate effectively. Many systems include a backup electric immersion heater for extreme conditions. Heat pumps actually work best when they run at low temperatures continuously, rather than in short bursts.
Do I need new radiators for a heat pump?
Not always, but often some upgrades are recommended. Heat pumps operate at lower flow temperatures (around 35–55°C) than gas boilers (typically 65–75°C), which means your radiators need sufficient surface area to emit enough heat. Our engineers will carry out a room-by-room heat loss calculation and identify any radiators that need upgrading. In many modern, well-insulated homes, the existing radiators are adequate.
Do I need planning permission for an air source heat pump?
In most cases, air source heat pumps fall under Permitted Development rights and do not require planning permission, provided certain conditions are met (such as minimum distances from property boundaries and noise limits). There are some exceptions — such as listed buildings, properties in conservation areas, and certain flat conversions. We'll confirm planning requirements as part of your free survey.
How noisy is an air source heat pump?
Modern air source heat pumps are relatively quiet, typically producing around 40–50 dB at one metre — similar to a refrigerator or quiet conversation. Planning regulations require heat pumps to emit no more than 42 dB at one metre from a neighbouring window. Noise levels drop significantly at greater distances, and siting the unit thoughtfully (away from bedrooms and boundaries) further reduces any impact.
Will a heat pump reduce my energy bills?
This depends on what fuel source you're replacing and current energy tariffs. Because heat pumps use electricity, their running costs are influenced by the electricity price, which is currently higher per unit than gas. However, their high efficiency (COP of 3+) partially offsets this. Many households see comparable or slightly lower bills, with costs expected to improve as electricity prices relative to gas decrease. The carbon footprint benefit is significant regardless.
Is my home suitable for an air source heat pump?
Heat pumps work best in homes that are reasonably well insulated and airtight. While they can work in older properties, the investment in any insulation improvements needed should be factored into the decision. Homes with underfloor heating are ideal candidates. We recommend a full heat loss survey before any decision — this gives you an accurate picture of suitability and likely running costs.
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