Stories from across the energy transition

Heating Up: The Power of Air Source Heat Pumps (Part 3 of 6)


Despite fully insulating our home, heating will always constitute a considerable portion of our energy consumption, especially in the UK’s cool climate and with a family demanding hot baths and showers. A pivotal aspect of our sustainable home project was replacing an antiquated gas boiler with an air source heat pump (ASHP), a more sustainable and efficient alternative to traditional fossil fuel boilers. In this third blog post, I aim to discuss the merits and considerations of ASHPs, along with shedding light on their cost-effectiveness, and available grants and incentives within the UK that make the switch an enticing prospect.

The Efficiency of Air Source Heat Pumps:

Air source heat pumps (ASHPs) can be a game-changer in residential heating, working on the principle of absorbing heat from the outside air, even in freezing conditions. By employing a refrigeration cycle, they collect heat from outdoors and efficiently transfer it indoors for space heating and hot water, guaranteeing homeowners comfort all year round. Efficiencies can reach 300-400% meaning these are highly favourable to direct electric heating.

Our Heating Project:

The boiler’s installation turned out to be more laborious than we initially anticipated. The heat pump’s output temperature is slightly lower than a traditional boiler, leading us to re-evaluate our home’s heat distribution. We collaborated with a heating engineer to assess the house’s heating requirements, given the newly improved insulation. Our final design involved underfloor heating for the ground floor and larger radiators on the first floor. We found a suitable south-east facing spot to position the heat pump next to a large wall, which we hoped would absorb additional radiant heat from the sun to boost the system. The unit required ample space for its size and ensuring sufficient airflow. To meet our heating and hot water needs, we installed a 12kW heat pump, which necessitated an electricity connection upgrade from 60A to 100A.

Energy Efficiency and Cost Savings:

ASHPs shine in their ability to deliver high-quality heating with significantly lower energy consumption than traditional systems. By drawing heat from the ambient air, ASHPs decrease energy usage, thereby reducing utility bills and providing long-term cost savings. We expect to see savings on our heating bills of over 50% per year by sidestepping gas costs and utilising solar electricity meaning thousands of points given the current high prices. The efficiency of the system will be interesting to watch through summer and especially into the winter.

Considerations and Grants:

As ASHP adoption gains momentum across Europe, potential adopters must be aware of several key considerations. These include having the appropriate type of cylinder and radiators or underfloor heating system, as ASHPs function at a slightly lower temperature than gas boilers. Sufficient installation space, adequate airflow, and a robust electric grid connection are also critical. To qualify for the current UK grant, homeowners must meet certain standards, such as having adequate insulation reflected in their Energy Performance Certificate (EPC).

The UK government’s Boiler Upgrade Scheme offers a generous £5,000 towards installing a new ASHP system, extended until 2028, providing homeowners and the industry ample time to benefit from this financial aid. Further, to make the transition more accessible, the VAT rate on ASHP installations has been slashed to 0% for the first five years.


ASHPs are a compelling option for homeowners seeking an efficient, cost-effective, and environmentally friendly heating solution. By tapping into renewable energy from the surrounding air, they not only ensure comfort but also contribute to reducing carbon emissions and promoting a sustainable future. As the demand for heat pumps continues to grow, the UK’s ambition of reaching its sustainability goals hinges on spreading awareness about the benefits, considerations, and incentives associated with ASHPs.

Fact: According to the Heat Pump Association, the UK heat pump market is growing fast, 30%+ every year, reflecting a burgeoning interest in this technology. Yet, to meet the UK’s goal of installing 600,000 heat pumps per year by 2028 a significant investment in skills and supply chain is needed. LINK: There is some significant support to ensure a rollout of Heat Pumps which we’ve discussed here UK receives £2.7bn upfront funding to boost grid capacity | Articles | CRA (

Next Post

Previous Post

Leave a Reply

© 2024 EnergyStory

Theme by Anders Norén