This blog series by Sustainable St Albans trustee Catherine Ross follows her journey, figuring out how to get off gas heating and the steps to consider before getting a heat-pump in her 1930s semi-detached home. Blog 1 introduces the context and subsequent posts will share the process of heat surveying, air tightness testing and the resulting action plan along with indicative costs.
Are you – like us – trying to figure out about this whole ‘heat pump’ thing?
We know the best thing environmentally is to stop burning gas – a fossil fuel – which means an electric solution of some kind. The most efficient option is a heat pump.
And we really, really don’t want to find ourselves in a position where our gas boiler breaks down and we have to install a new one, just because we’ve run out of time to think about other options.
We live in a 1930’s semi-detached house, much extended by the previous owners at different times in its life. We know it needs a new front door and new windows on the back; they leak cold air. But do we need to go further?
We decided in January 2022 that this year would be the year of gathering information: What would it really require? What would it really cost? Is it worth the money?
We also want to share what we found out to help other people up the same learning curve.
Isn’t the solution obvious? Just get on and install a heat pump.
It’s not as easy as it sounds, because heat pumps work efficiently heating the water circulating in the radiators to a lower temperature than conventional gas boilers. This means that for heat pumps to work well, and keep people comfortable, it generally also means;
- Reducing heat loss, through insulation, improved windows, dealing with draughts and
- Installing bigger radiators.
We’ve already done a lot at our house; new double-glazing on the front, loft insulation, solar panels. But we still find the house gets cold quickly when we turn the heating off, which we do as much as we can, so we know more changes to the fabric are needed.
Our first step: engage an architect, and get a proper survey.
Step one was to get advice. We spoke to local architects, AD Practice, who have done several local retrofits and passive houses.
Through AD Practice, we commissioned an Energy Efficiency Assessment, consisting of an airtightness test and a thermal imaging survey. The architects then used the results to give us a high-level set of costed recommendations.
A thermally efficient home has three main components:
- a well-insulated building fabric, helping to minimise heat gain in summer and heat loss in winter (checked through the thermal imaging survey)
- airtightness, to minimise draughts coming in or air leaking out (checked through the air-tightness test); and
- controlled ventilation.
For our house to be ‘heat-pump-ready’, we need to reduce the space heating demand, which means the building envelope needs to be both insulated and airtight.
Our next posts will share the results of the Thermal Imaging Camera, the Air Tightness test and the full Recommendations report too. We really hope our experience can be useful for other people. Once we’ve installed everything, and gone through a winter with the new heating system, we’ll write another blog to let you know how it all went!