Annandale Estates located near Lockerbie has undertaken a project to convert a traditional stone barn into four energy efficient affordable homes. The Raehills Home Farm development was designed by White Hill Design Studio and challenged contractors to retrofit the draughty disused agricultural building into warm modern homes as close to Passivhaus standard as possible.
The estate was keen to ensure any new development was of a standard which would allow for tenants to gain the benefits of consistently comfortable temperatures achieved at a low cost.
A planning application was submitted at the end of 2011 and tenants moved in at the beginning of 2017. The homes are all occupied at affordable rents and help to meet the local demand.
The buildings have substantial insulation lining the existing stonework. In order to ensure good air quality and eliminate any potential damp issues, mechanical ventilation and heat recovery systems were installed. These systems automatically remove warm damp air from the kitchen and bathrooms and recirculate this as dry warm fresh air to the bedrooms and living areas. The properties also have large windows to allow plenty of light and warmth from the sun.
Since moving in, all but one of the homes have required no heating whatsoever and the tenants are delighted with their predictably low energy bills. The intention is that the running costs for a two bedroomed cottage should be in the region of £600 per year all in.
The houses are completely powered by electricity, including the hot water, which is supplied by a private grid where the electricity is sourced from either a hydro scheme or a combined heat and power plant, or the solar PV panels on the roof. They are in effect completely green and off the grid.