Frequently asked questions
Unsure or mystified by the potential of heat pumps?
Here's our perspective on questions we are often asked*
Is my home ready for a heat pump?
Contrary to what some might think, you don’t need to own an ultra-modern, highly insulated home to run a heat pump. Take comfort that we’ve successfully installed heat pumps in all sorts of homes including country cottages, barn conversions, Victorian homes, large properties and more. Contact us for trusted advice on whether or not your home is suitable for a heat pump.
What exactly is a heat pump?
A heat pump uses technology similar to that found in a refrigerator or an air conditioner. It extracts heat from a source, such as the surrounding air, geothermal energy stored in the ground, or nearby sources of water or waste. It then amplifies and transfers the heat to where it is needed. More specifically, a heat pump generates heat by capturing an ambient heat source using the refrigerant liquid before compressing it to a higher temperature for central heating use.
Because heat pumps transfer heat energy from one place to another rather than generating it from burning, they are far more efficient than conventional heating technologies such as boilers. Heat energy output is normally several times greater than the electrical energy required to power the heat pump.
How do heat pumps work when temperatures are low?
Air source heat pumps can be effective down to -20°C because refrigerant can still boil at -20°C. However, the colder the air, the harder the system must work, and the more energy it needs. With ground source heat pumps, the refrigerant is warmed by the ambient temperature of soil at 1.2m deep, which is usually 7°C to 12°C all year round.
Am I using electricity to warm my home?
Most of the time, a heat pump only uses electricity to power the pumps, system and compressor to generate heat. Depending on the brand of heat pump, direct electrical heat is sometimes needed to defrost the outside unit when it gets iced up. A hot water cylinder might sometimes use direct electrical heat, such as during a sterilisation cycle.
How efficient are heat pumps?
Manufacturers are finding increasingly ingenious way of making heat pumps efficient and the latest ASHP units can generate up to 5 units of heat for every unit of electrical energy used by the compressor. This ratio is called the COP (or co-efficient of performance). In the real world, the COP will be lower in winter times when the ASHP needs to work harder in colder temperatures. The average COP over the year is called the seasonal co-efficient of performance or SCOP. In our experience, SCOPs are usually about 3.6 to 4.6.
Are ASHPs expensive and are grants available?
Many of our customers are surprised at just how affordable a heat pump can be. And residents in England or Wales can also get a £7,500 grant towards a new air source or ground source heat pump from the Government's Boiler Upgrade Scheme. As an MCS accredited installer, we will do all the paperwork and simply deduct the cost from your bill.
Are ASHPs cheaper to run than oil or gas?
Customers living in ultra-efficient homes may see their fuel bills go down with an ASHP. For the rest of us, most customers tell us their systems have about the same running costs as oil. This is not surprising as 1kWh of electricity has historically been about 3 to 4 times more expensive than 1kWh of oil - which is about the same ratio as the average SCOP of 3.6 to 4.6. For gas, the cost advantages may harder to prove. However, ASHPs emit a fraction of the CO2 emissions of oil and gas so the environmental benefit is clear. If running costs are a priority for you, why not consider also investing in a home battery? You could then charge it with cheap-off peak electricity and power your home with it at other times of the day. See our Services page for more details.
Can I install an ASHP in an older home using only radiators?
The simple answer is usually yes, but we will only know for sure once we have conducted a heat loss survey. In theory, a heat pump works most effectively in a highly well-insulated house using underfloor heating. But ASHPs can also be an effective direct replacement for a gas or oil boiler in other types of home too. Customers can be confused when they learn that conventional boilers circulate hot water through radiators at up to 60C whereas it is more usual to run an ASHP at 35 to 45C. However, the heat loss survey may well show your home can be heated with conventional radiators at this lower temperature as well because the ASHP will run for longer but at a lower temperature instead of the intermittent bursts of heat that a conventional boiler gives out. In our experience, we have installed many ASHPs using only conventional radiators without underfloor heating. In most cases, it has usually been necessary to increase the size of some radiators. We will advise of these requirements as part of the heat loss survey. We are also keeping a close eye on industry trends as some new ASHP models can now warm water up to 60C or even 80C, although they will not be operating at their most efficient at these temperatures.
Are ASHPs noisy?
ASHPs usually run quietly and our customers say they are neighbour friendly. In winter, when ASHPs have to work harder, noise will increase.
Can I power my ASHP with solar panels?
Electricity generated from Solar PV can certainly contribute to the running of your ASHP but it's unlikely the panels will generate enough power for the unit to go fully "off grid". Some of our customers have installed a battery to store PV power for use by the ASHP at key points in the day (such as at night time). In the bigger scheme of things though, be reassured that your ASHP, solar PV panel and battery components can all contribute to cutting greenhouse gases, even if you are still reliant on the grid for uninterrupted power supply.
Do I need planning permission?
In many cases, planning permission is not required. However, approval might be needed in some circumstances such as with larger installations or if work is happening on a listed building. We can advise you when we conduct the heat loss survey.
Do I need a well-insulated home?
The answer is an emphatic yes! Before anything else, please invest in good insulation before considering any other renewable technology such as a heat pump. Otherwise you will be wasting your money in unnecessarily heating and contributing to greenhouse gas emissions.
Will I create emissions further up the chain?
Heat pumps do not burn fossil fuels like a gas or oil boiler. Instead, they are powered by electricity and the UK’s National Grid is increasingly decarbonising thanks to huge investment in wind, solar and nuclear power. What’s more, because a heat pump is so efficient, the carbon impact of its output is about quarter of the electrical energy it uses meaning the overall carbon impact is a fraction of a boiler running on a fossil fuel.
* Please note that this FAQ is given in good faith and is based on our general observations and experience of client installations. They should be read as general advice only and not a service guarantee. Every home and business is different and we will endeavour to find a suitable system for your home or advise you of any uncertainties.