Kestrel Lane, Wellingborough

Project: Kestrel Lane

Client: Lovell – self-funded retrofit project

There is no Code for existing housing, of course, but we did not want to wait for the Government to devise one before we developed a robust process designed to address the existing housing stock. With existing homes accounting for 27% of the UK’s carbon emissions, it is a sector that simply can not be ignored.

Working with Northamptonshire-based Wellingborough Homes, we identified a three-bedroom terraced home, built in the 1970s. We used our expertise in the refurbishment market to not only work to the highest standards but also to complete the work as economically as possible so that our model was a realistic and affordable one for councils across the country.

The house is set to achieve a 62% reduction in CO2 emissions against current building regulations for a house of a similar size. The house should save 3,600kg worth of CO2 a year - an 89% reduction in emissions from the original dwelling. In comparison, a new home built to Code Level 4 would save 1,000kg of CO2 a year.

Current market costs for a similar retrofit is in excess of £40,000. This project was completed for less than £18,000.

The project can be completed alongside existing planned Decent Homes work in around 20 days.

Specification

A 2.1KWP array of photovoltaic panels were fitted to reach a target of zero energy bills for heating and lighting. It is anticipated that the PV panel will produce £740 through a Feed-in Tariff and provide a saving of £201 on electric bills each year.

A mechanical ventilation and heat recovery unit provides a heat recovery system to recover 60-70% of the heat normally lost through trickle vents and other breakout points in the building.

A gas saver ‘top box’ sitting between the boiler and flue reuses flue gasses to pre-heat incoming mains water to reduce gas consumption. This will achieve a 40% reduction in gas use.

Loft insulation was increased to 400mm. Cavities were filled with insulation. Knauf internal wall insulation system was installed. Thermally engineered insulated studs were incorporated. Earthwall EcoBatt – water repellent grasswool – was used. As a result of these measures the wall U value increased from 0.9 to 0.3.

The final air test showed the volume of air escaping had reduced from 7.8m3/(h.m2) to 4.02m3.

• Eco bins fitted with three separate compartments.

• Water efficient sanitaryware and fittings, with flow limiters fitted to all taps, a dual flush WC, eco-shower and 169 litre bath.

• Space for home working.

• Sun pipe to improve levels of natural lighting to the first floor.

• Water butt installed.

• Eco paint used containing 35% less embodied carbon.

The home was refurbished to support Lifetime Home standards. Features include level access to front and rear doors, and spurs fitted to accommodate a stair lift. There are additional space requirements in the bathroom together with a shower gully fitted beneath the bath for future conversion to a level access shower.

All windows and doors are Secured by Design compliant to provide high levels of security.

During the project we hosted three visits by school groups, which enabled the pupils to find out more about the house and its features. These schools are now engaged in a competition to design their own house of the future.

“In this project, we have taken the retrofit theory and put it into practice. Our objective was to deliver a sustainable solution, which was affordable for Wellingborough Homes and beneficial to the tenants. Our results have met the initial objectives and we are now recording energy efficiency performance and working on continuous improvements. Affordability has improved significantly in comparison to other schemes within the industry. We now intend to roll this initiative out to other authorities and associations within the region as part of our commitment to achieving green improvement targets and greener living.”

David Gough, Regional Director, Lovell