What Is A Heat Pump And Should You Get One?

The principle of how heat pumps work involves pumping a refrigerant through a network of pipes. The refrigerant flows through the “warm” area (outdoors or underground) and absorbs heat, evaporating into a gas. It is then pumped through a compressor, further increasing the gas’s pressure and temperature. Now, these hot gases enter the “cold” area, where they condense back into a liquid, releasing a significant amount of heat energy into the heating system.

 

Why Are Heat Pumps So Efficient?

Traditional heaters convert electrical or chemical energy into heat energy. Modern gas boilers have an efficiency of over 90%, meaning that for every 1 kilowatt-hour (kWh) of energy burned, more than 0.9 kWh is ultimately used to heat your home. Electric heaters have an efficiency of 100% – they convert 1 kWh of electrical energy into 1 kWh of heat.

 

This may sound impressive, but well-designed heat pump systems can achieve efficiencies of around 350%! The reason is that heat pumps don’t generate heat; they simply move existing heat from one place to another. A heat pump consuming 1 kWh of electrical energy can move 3.5 kWh of heat from the outdoors to indoors.

 

This performance significantly reduces the operating costs of heat pumps compared to traditional electric heating systems. Additionally, unlike gas boilers, you can power heat pumps with renewable energy, making them a carbon-neutral technology.

 

What Are the Drawbacks of Heat Pumps?

Unfortunately, heat pumps do have some drawbacks compared to traditional heating systems. While heat pumps are highly efficient, their efficiency is highest when heating at lower temperatures, typically up to around 40°C, rather than 55°C or higher like gas boilers. Therefore, they are best suited for well-insulated homes with larger heating areas, such as underfloor systems.

 

GSHPs can operate year-round, whereas ASHPs are highly sensitive to outdoor air temperatures. They can work in cold and freezing conditions but need to work harder, resulting in lower efficiency during winter peak demand.

 

All heat pumps have slower heating times compared to traditional systems—you can’t expect to turn on a heat pump and have hot water for a shower in 30 minutes. Additionally, because heat pumps heat water at lower temperatures, larger water tanks are generally required to store more hot water.

 

You can mitigate the primary limitations of heat pumps by installing them in hybrid systems, using the heat pump for basic heating, and relying on a traditional boiler for rapid additional heat when needed. However, new homes designed for heat pumps without boilers will optimize their performance through stricter insulation and windproof standards.

 

What Are the Costs of Heat Pumps?

Typical ASHP installations cost around £5,000-£8,000, considerably higher than the £2,000-£3,000 cost of traditional gas heating. GSHPs are even more expensive, costing around £10,000 or more. However, both systems are eligible for the government’s “Green Homes Grant,” which can provide up to £5,000 toward installation. They also fall within the scope of the Renewable Heat Incentive (RHI), which pays homeowners for using renewable energy for heating. Payments are made quarterly and continue for seven years after installation.

 

These grants can help offset the high installation costs of heat pumps, and over time, heat pumps may become cheaper than traditional heating even without these incentives. According to calculations by the Energy Saving Trust, the cost of heating with natural gas is approximately 4.6 pence per kWh, while electric heating costs about 9 pence per kWh (using Economy 7 rates). The cost of using a heat pump with standard electricity rates is approximately 4.7 pence per kWh.

 

This makes the operating costs of heat pumps comparable to gas heating but potentially cheaper with Economy 7. If you have solar panels installed, your operating costs could be very low.

 

The UK government has consulted on “Future Homes Standards” for energy efficiency measures in new homes. One proposed amendment is to ban the use of gas boilers in new homes from 2025. While this is not yet government policy, boilers as we know them will inevitably be phased out in the coming decades. As one of the primary practical alternatives, heat pumps are set to become more common as we upgrade to the next generation of heating and insulation technologies to meet our future environmental goals.