A heat pump is an alternative heat source to gas or electric boilers. They produce hot water for wet central heating systems, distributing heat to radiators and a stored hot water cylinder.
They work by harvesting heat from the environment (either from the air or underground).
Air Source Heat Pump
In the case of ASHPs, a fan draws in the air. This air then passes over an evaporator containing a refrigerant gas which harvests the heat from the air. The refrigerant turns from liquid to gas at low temperatures, and this gas passes through a compressor, which compresses the gas and further increases its temperature. This “hot” gas then passes through a heat exchanger, which transfers the heat into the “wet” central heating circuit, heating the radiators and cylinder.
Ground Source Heat Pump
A GSHP harvests heat from the ground. A coil buried in the ground has a refrigerant solution pumped through it, drawing heat from the ground. This heat is used similarly to the heat harvested by air source pumps.
“I’m told they only work when the air is warm.”
It’s understandable to believe this to be the case, but it’s not actually true
Heat pumps work effectively in ground or air temperatures as low as minus 15 degrees centigrade. They are used to significant effect in Scandinavia, where temperatures reach minus 10 in winter.
“Yeah, but what are the real benefits?”
There are several benefits to using heat pumps instead of more traditional heating options:
- They will lower the costs of heating your home compared to using gas – even more so if converting from Electric, LPG or oil.
- The carbon emissions are 70% less than fossil fuels, as they use air, which is a renewable source.
- They will typically last for about 20 years (the average life span of a gas boiler is 12-15 years)
- Environmentally friendly, no plumes of condensate or co2 gasses, which can worsen air quality.
- Safer than fossil fuels, there is no combustion process to worry about, meaning there is no risk of carbon monoxide leaks.
- No gas means no gas leaks and potential explosions to worry about and a reduced fire risk.
“Do they use a lot of electricity?”
They do use electricity, as so do conventional systems. However, much of the electricity produced now comes from renewable technology, making it more eco-friendly.
“There is always a downside, right?”
They aren’t perfect, and your property may need some alternatives to allow heat pumps to work at maximum efficiency.
- Heat pumps produce less heat than boilers, so in some circumstances, properties will need larger radiators.
- Heat pumps will not typically work well alongside a combi boiler, so a high recovery unvented cylinder is the best design solution.
- Investing in better insulation and draught-proofing will always be beneficial, even with traditional gas-fired systems.
- You need outside space, but could free up internal space by removing your old boiler.
Are Heat Pumps The Future?
As a planet, we must look at renewable energies, not only due to the shortages in fossil fuels but also due to environmental issues. There have been many proposals in the past, and the uptake and adaptation have been slow. However, with the advance in the development of these technologies, solutions are getting better and more affordable.
Some say heat pumps are not renewables as they require electricity to run, but they are if this electricity is from a wind or solar farm. The energy output is several times the power input, so most heat comes from renewable sources.
The cost of installation and upgrades in existing properties can be off-putting. Still, with grants and incentive schemes available from the Government, a decent proportion of these costs are being subsidised.
We have to make a change. We have to make it now.
