Environmental benefits

At Atelierdb Architects, we think every opportunity to champion new low carbon technologies should be embraced inline with the UK government’s Net Zero 2050 target and the Royal Institute of British Architects (RIBA) 2030 Climate Challenge. And there’s no doubt that air source heat pumps are far better for the environment than traditional gas boilers. According to research carried out by EDF Energy, an air source heat pump could cut the carbon emissions your home produces by more than 23 tonnes of CO2 over 10 years.

Affordability

According to Energy Savings Trust, a typical air source heat pump costs around £14,000 to install. At the moment UK government grants – via the Boiler Upgrade Scheme – are available for homeowners across England, Wales and Scotland who are keen to make the leap from gas boiler to air source heat pump. However, while the grant is a significant lump sum, the reality is that costs can almost double if you undertake installing an air source heat pump as a standalone project. Affordability becomes less of an issue when undertaking the changeover in conjunction with other home alterations, like an extension, internal renovations, or whole house reworkings.

Return on investment

Similar to solar panels, a lot of homeowners won’t see an immediate return on investment from installing an air source heat pump. However, this depends on how you measure that investment: Depending on your energy tariff and the efficiency of your old heating system, your energy bills should be lower over time because air source heat pumps are far more efficient than gas boilers. Another measure is the appeal of a well-implemented, energy efficient and environmentally friendly heating system to add significant value to homes for future buyers, although this is harder to quantify at present.

How air source heat pumps work in historic homes

In cities, towns and villages across the UK there’s a wealth of Georgian and Victorian terraced housing, and post-war semi-detached and detached homes. The majority of these period properties have solid brick external walls which offer poor levels of insulation and lose heat through conduction (warm air leaking through walls), and via ventilation (draughty windows and doors).

The efficiency of air source heat pumps in historic and period homes is dependent on a number of critical factors:

• How well the main elements of the house are insulated, ie – roof, walls, floor and windows
• How airtight the house is; a leaky house will need a larger air source heat pump to compensate for the heat loss (and require more energy consumption)
• The size of radiators and/or underfloor heating already in place
• Any additional ventilation systems that already exist or have been added to the house

Air source heat pumps have been proven to work in modern buildings built to Passivhaus standards which are super-insulated and airtight, with whole house ventilation systems controlling air supply and extract. But emerging research shows that air source heat pumps can also be successfully installed in the UK’s period and historic homes, and – crucially – provide the same level of comfort as traditional gas boilers. It can only benefit the efficiency of ASHP’s by adding in more insulation and making historic buildings more airtight – but in consideration that condensation also must be addressed. At Atelierdb we can help find the right balance and help retrofit projects grasp latest technologies and save energy becoming more efficient.