If we had a pound for every time we heard the words: ‘heat pump’, in the last week; we’d be rich! Heat pumps have been dominating the news; ever since the government released its new ‘Heat in Buildings’ strategy ahead of COP26 next week.
The government’s ambition is to be installing 600,000 heat pumps per year by 2028.
But what are heat pumps and what’s the big deal?
At its simplest, a heat pump is a device that transfers thermal energy from one point to another. They look a bit like air conditioning units.
Although they use electricity to run; they’re considered a much greener way of heating your home. Unlike your boiler, they don’t need to burn fuel (usually gas) to create heat.
When we burn fuel, we’re releasing carbon dioxide into the atmosphere; which is what we’re trying to reduce in our battle against climate change. Although modern boilers are much more efficient than they used to be; (partly due to Boiler Plus), they still release some emissions.
Heat pumps emit less carbon emissions than boilers, but they still need to use electricity to drive the pump. So, they’re not completely zero-carbon unless the electricity is provided by a renewable source, such as solar power.
Are gas boilers being banned?
Because of the media frenzy regarding a supposed ‘boiler ban’; we dedicated a whole blog to this question – you can read it here.
But in short, the government has announced an ambition to phase out the installation of new gas boilers beyond 2035; in favour of ‘greener’ alternatives. This won’t impact your current boiler, and you can still replace your current one until 2035.
But in the future; we’re likely to see a combination of both hydrogen boilers and heat pumps being used to heat our homes; hence this blog!
How heat pumps work
At its simplest, heat pumps transfer outside energy into heat for your heating and hot water system.
Some heat pumps extract energy from the air, and these are known as ‘air source heat pumps’. Another type of heat pump extracts energy from the ground, and these are known as ‘ground source heat pumps’.
As their name suggests, they pump heat. They take energy (from the air or the ground) from a low temperature source; and force that heat to a higher temperature for our heating.
Heat pumps are often compared to a refrigerator to explain how they work. This immediately seems odd because your fridge is cold, right?! But fridges don’t work by making the inside cold, they work by pumping the heat out, thereby cooling the inside.
So, an air source heat pump works like a reverse fridge. It extracts warmth from the outside air before concentrating it. It then transfers it into your home to provide heating and hot water.
Ground source heat pumps work in a similar way. But they collect heat from pipes running underground, rather than from the air.
The different types of heat pumps
As we’ve mentioned, there are two main types of heat pumps, air source and ground source. Let’s take a closer look at each…
Air source heat pumps
An air source heat pump works by using a fan to draw in air from the outside. It absorbs the heat into a liquid refrigerant.
Using electricity, the heat pump compresses the liquid to increase its temperature.
It then condenses back into a liquid to release its stored heat. Heat is sent to your radiators or is stored in a cylinder for later use.
Air source heat pumps are easier to install than ground source. This is because they don’t need the network of underground pipes that a ground source heat pump requires.
Ground source heat pumps
Ground source heat pumps collect heat from the ground through a network of water pipes buried underground.
A mixture of water and anti-freeze is pumped around the network of pipes; and absorbs the naturally occurring heat in the ground. This heat is then transferred to a liquid refrigerant inside the heat pump.
At this point, the process is the same as with the air source heat pump. Electricity is used to compress the liquid refrigerant to increase its temperature. It then condenses back into a liquid to release its stored heat. Heat is sent to your radiators or is stored in a cylinder for later use.
Ground source heat pumps are more expensive than air source heat pumps; because of the network of underground pipes that need to be installed. But they do tend to be more efficient.
Do heat pumps work as well as a conventional boiler?
As soon as any new initiative is launched, you can expect some scare mongering in the news and social media! But heat pumps (when properly fitted by an expert) are just as good; and in many ways better; than a conventional boiler.
Despite what you might have read online; properly installed heat pumps are more than capable of keeping your home warm on the coldest of days.
It’s understandable that people are concerned about how a device is going to absorb heat from the ground when it’s snowy out. But there’s no need to worry!
In the UK, the temperature of the ground doesn’t usually fall below 10 °C. Although you might think that’s a bit nippy, there’s still heat in the ground for the taking. Air source heat pumps will use ambient heat.
Heat pumps are much more efficient than your gas boiler, producing around three times the amount of energy they use! According to Octopus Energy, for every kW of electricity given to a heat pump, it creates between 2-4kW of heat.
What does it cost to install a heat pump?
The cost of installation varies depending on what system is being installed. The only way to find out how much it’ll cost for your home is to get an initial survey completed.
But heat pumps are currently much more expensive than gas boilers.
The Energy Saving Trust estimates that a typical air source heat pump installation will cost you around £6000 – £8000.
A ground source heat pump installation can cost £10,000 – £18,000 depending on the amount of heat required.
The government is currently looking at how to reduce the cost to encourage uptake. You can currently apply for funding for a heat pump under the Renewable Heat Incentive. And there will also be grants of £5,000 through the new Boiler Upgrade Scheme.
What financial help is there to install a heat pump?
The government is giving households grants towards the cost of installation; to try and achieve its target of installing 600,000 per year by 2028.
Under the new ‘Boiler Upgrade Scheme’; grants of £5,000 will be made available to help households install air source heat pumps. There will be grants of up to £6,000 available towards the cost of installing a ground source heat pump.
The government has set aside £450 million for the grants, with the total money allocated enough to cover 90,000 homes.
The grants will be available for three years from April 2022. Details of how to apply are yet to be published. Unfortunately, the scheme is likely to be massively oversubscribed.
You can already apply for funding via the Renewable Heat Incentive (RHI) until March 2022. Buyers must pay for the work upfront; and then reclaim the RHI payments; which are paid quarterly for the first seven years of ownership.
What savings can be made with a heat pump?
If you’re replacing a G-rated gas boiler with an air source heat pump, you should reduce your energy bills. But right now, not by a lot. And in fact, there are concerns that people might end up paying more each year.
Why is this?
Well, even though heat pumps are much more efficient than gas boilers; electricity is currently three times the price of gas!
This is because there are higher environmental levies on electricity. This adds 23% to energy bills while gas only has a levy of less than 2% – to subsidise renewable energy. But the government is hoping that will switch around as more heat pumps are installed.
What are the advantages and disadvantages of installing a heat pump?
86% of UK homeowners currently rely on gas central heating. So how does a heat pump compare?
Advantages of heat pumps
Let’s start with the advantages of heat pumps…
They are incredibly efficient
One of the biggest advantages of heat pumps is that they’re incredibly energy efficient. This is referred to as the Coefficient of Performance (CoP).
The CoP is the amount of heat generated for every kilowatt of electricity used. An air source heat pump can convert each kilowatt (kW) of electricity into 3-4 kW of heat.
This means that they’re between 300%-400% efficient!
This is pretty impressive when you compare it to a modern gas boiler with an energy efficiency of about 92%!
Heat pumps manage this impressive energy efficiency because they transfer heat rather than generate it.
They can save you money on your energy bills
Because heat pumps are so efficient; they can save you lots of money on your energy bills (certainly once the price of electricity comes down!)
To illustrate this, think about a modern boiler with 92% energy efficiency. This boiler will use 92% of the supplied energy for heating your home. But the remaining 8% of energy will be lost in the process of generating heat. So, this means that for every £1 you spend on heating your home, this boiler is wasting 8p!
Now think about a heat pump with 300% energy efficiency. Not only is this heat pump not wasting energy, but it’s also giving out more than you put in. Hopefully it’s now easy to see what a positive impact a heat pump can have on your energy bills!
They reduce your carbon footprint
The government is pushing heat pumps because they’re much more environmentally friendly than gas boilers.
According to EDF Energy; installing a heat pump could cut your carbon emissions by more than 23 tonnes of CO2 over 10 years. That’s the same as 30 return plane flights between Heathrow and Madrid!
Heat pumps use some electricity to run. But if you’re able to power them with electricity from renewable sources; such as solar power; they are completely carbon neutral.
They require minimum maintenance
A good quality and well installed air or ground source heat pump system will require relatively little maintenance. You’ll just need an annual check which can be done either by a qualified installer or engineer.
There is financial help available for installing a heat pump
Whilst the cost of installing a heat pump is currently high, there is some financial help available. You can already apply for RHI payments. And the new £5,000 Boiler Upgrade grants will shortly be made available to 90,000 homes over the next three years.
Disadvantages of heat pumps
As with all things, there are always some drawbacks…
They have a higher upfront cost
Whilst installing a heat pump is pricey; it’s important that you weigh that against the pay back you’ll get on your energy bills. And don’t forget the environmental benefits!
If you’re able to get a government grant; the price of your new heat pump will be comparable to a gas boiler.
It’s also likely that the price of heat pumps will come down. But by just how much, is yet to be seen.
They are not 100% carbon neutral
This isn’t really a disadvantage as such because heat pumps are much more eco-friendly than traditional gas boilers. But it is important to be aware that heat pumps are not 100% carbon neutral. This is because they use a small amount of electricity to run.
If you want to be completely carbon neutral; you’ll need to run your heat pump on electricity from a renewable source such as solar power.
They won’t save you as much on your energy bills until the cost of electricity comes down
As we mentioned earlier, electricity prices are currently very high, particularly in comparison to gas. But it’s important to remember that heat pumps are so efficient; they can convert a unit of electrical energy into 2-4 times as much heat energy. There is also pressure on the government to look at electricity costs to improve uptake. So watch this space…
They are tricky to install
Heat pumps are more complicated to install than conventional boilers. And there’s a lot of excavation work required for a ground source heat pump. As with all heating installations, it’s important to get a qualified engineer to conduct the works.
They need good property insulation
Again, not so much a disadvantage per se, more like something to be aware of. But for heat pumps to work as they should; it’s important that your home is well insulated with double glazing; cavity wall insulation; and a decent level of roof insulation.
Final thoughts…
Heat pumps are a significant part of the government’s strategy to keep the UK on track with its goal of being carbon neutral by 2050. They’re a great choice as an eco-friendly approach to heating our homes.
But they’re not the only choice. The government is also looking into using hydrogen for heating but wants to see results from a pioneering ‘Hydrogen Village’ before it makes further decisions. So watch this space!
Useful links
Government Heat in Buildings Strategy – October 2021
Worcester Bosch video explaining heat pumps
Renewable Energy Hub guide to Heat Pumps
The Guardian article on heat pumps: The costs and savings stack up
The Guardian article: What are heat pumps and why are the government pushing them?