What first inspired you to undertake your project – what did you hope to achieve?
Prior to moving in 2021, I lived in a 1998 new build semi-detached two-up to two-down cottage in Warwick. Despite double glazing and cavity wall insulation, the house was cold and expensive to heat, and there was always damp and mould on the double-glazed windows and in the bathroom. Since the house was subject to Deeds of Covenant, I couldn’t make the changes I needed and wanted to make:
- Reduce the costs of heating
- Reduce the mould and damp
- Save the planet
What type of project did you undertake?
- Retrofit and renovation of a 1960s chalet bungalow
- Extended the dormer across the full length of the property to increase the useable space of the upstairs rooms.
- Internal insulation: 100m Celotex and Mannok (Cold attic)
- Bamboo flooring with insulation underneath
- Mechanical Ventilation and Heat Recovery (MVHR)
- Double glazing and composite doors
- Replaced 1970s night-storage heaters and immersion heater with air-source heat pump and radiators (There is no gas in Pewsey)
- (Electric underfloor heating under tiled bathroom floors (as yet unused!)
- 12 solar panels and 2 x 5K batteries
Could you tell us any interesting facts or remarkable features about your project?
- High ceilings and double height hallway
- Very large windows relative to floor area and lots of light!
- Very solidly built: cavity wall, cement blocks and brick outside
Before:
After:
Kate's Experience at the National Self Build & Renovation Centre:
How many times have you visited The National Self Build and Renovation Centre before?
Once in person before Covid and three online surgeries during Covid (insulation, windows & heating options (air-source heat pumps), and once after in 2020.
What would you say is the most helpful feature or resource at the NSBRC?
- Lots of stands to look at - they gave me ideas of what was possible.
- The Renovation House and the air source heat pump displays
What did you enjoy most about your visit to the NSBRC?Seeing ‘the art of the possible’.
Did you use any exhibitors at the NSBRC? If so, who?
Total Home Environment. Absolutely super service and I wish I had gone with them for both the MVHR and the air-source heat pump and heating.
Would you recommend the NSBRC to a friend, and if so, what aspects of the Centre would you recommend and why?
Original Floor Plans
Final Floor Plans
N.b. If you go for internal insulation, it is very important that damp doesn’t build up between the wall and the internal insulation.
Normally a breathable, waterproof membrane would be fitted to the wall prior to the internal insulation.
I have mechanical ventilation and heat recovery (MVHR) running all the time, so damp and mould is less of a risk, and I didn’t fit a membrane to the original internal walls.
This chart shows the relative costs of heating a modern100m² house in Warwick with a gas-combi boiler, then moving to the Pewsey 200 m² house with 3 night-storage heaters on very low and an immersion heater for hot water. (I was very cold!). After the MVHR, ASHP with radiators went in, the Pewsey house is a comfortable 20’C in mid-winter.
This chart shows the impact of adding solar panels and batteries on the electricity imported from the grid to run all the appliances, ASHP, MVHR and lights the Pewsey house. In the summer, the house is almost self-sufficient, saving an average of 8kWH/24 hours. On cloudy wet winter days, the saving is less (approx. 3kWH/24 hours) but on bright cold days, the solar panels provide more electricity to help run the harder working ASHP.
Return on investment: solar panels and batteries
Saving
£1000 p.a. on electricity bills
+ £265 p.a. export
Payback of 12 years
Return on capital employed = 7.9%
(tax free)
