THE desire for a utility room brought Michelle Sutherland and Neil Thomson to the ‘passive house’ they built in North Berwick. The couple and their two children, Maja, 7, and Lois, 5, were already living in the town, in a Victorian ground-floor flat which they had refurbished and reconfigured with the help of architect Julie Wilson of Brennan & Wilson Architects.
They had considered building a house after relocating from the Highlands to East Lothian in 2005, but realised that any plots were outwith their price range, so decided instead to buy a period property and inject it with new life.
“We thought we’d be there forever,” Michelle reflects. The only thing missing from the reconfigured flat was a utility room, so the couple decided to add one and started researching online, which is when they spotted this plot for sale. Michelle says: “We wanted a space for our washing machine and ended up building a house!”
Neil, a corporate finance adviser, and Michelle, an employment lawyer, share an interest in environmental design. “For both of us the environmental angle was the thing; that’s what drove us to Julie’s practice initially,” Michelle reflects, and the couple turned to Julie again when designing this house.
The couple considered various options, from ground source heating and wood pellet biomass boilers to grey water harvesting, before coming to a simple realisation that led them to the passive house concept.
“Essentially, having a house that’s as well insulated as possible makes sense, rather than having the heat leaking out,” Neil says. “It was an education for us,” Michelle acknowledges. “We thought a passive house meant no heat, and it can mean that, but there’s a limit to the amount of heating required in order for a house to be officially classed as passive.
“The key thing is creating an airtight building, with lots of insulation and no cold bridging – so there’s as little material contact between the outside and the inside skin, as the more connections you have, the more heat is conducted through it.” In terms of airtightness, a passive house requires a level of just 0.6m3 per m2 per annum.
So what does that mean in real terms? It means super-low energy bills, at a time when the rest of us are facing escalating costs and crippling winter gas bills. When considering an airtight house, you might imagine there is a lack of air, but a mechanical ventilation heat recovery system (MVHR) is used to remove the heat from the extracted air and use it to heat the incoming air. “There’s more fresh air in this house than there would be in a leaky house,” Neil says. “It’s just circulated in a controlled way.”
A key factor in any passive house is the quality of the build required to achieve an airtight building. “It requires careful building and getting your builders on board,” says Michelle. Reywood Construction came up with the goods for them. Julie also suggested hiring a quantity surveyor. “We didn’t understand why we’d need one at first,” Michelle admits. “The QS we worked with, Chris Ward, told us that his fee would be reaped back a number of times in controlling the costs. He was right. We couldn’t have done this without him.”
Budget was an issue for the couple, particularly as they sold their last property only when this house was completed last summer, and they focused on the fundamentals. “We made compromises to afford the things you can’t see, like the recycled glass insulation, and things you don’t notice, like the triple glazed windows,” Michelle explains. The house is timber framed, and heated by solar gain through large south facing windows, incidental gains from appliances, lighting and people and three low output electric towel rails, with heating back-up provided for colder days by a small electric coil in the MVHR ventilation system.
Photovoltaic panels can generate up to 3.7kW of electricity – more than half the family’s electricity requirements for the year – while solar panels provide hot water for at least six months of the year. This four-bedroom house achieved an A rating of 97 on the Energy Performance Certificate.
“One of the reasons we wanted to do this was to say, you can do it for the same money as you would spend building a non-passive house,” Michelle says. “We didn’t want to put other people off.”
In the end, they finished under budget. They bought the kitchen online (it was an ex-display model) a year before the house was built. Energy efficient LED lighting is used throughout, while the slate countertops used in the bathrooms came from reclaimed snooker tables. The couple even made the industrial-styled pendants that hang over the dining table using old fishing chains.
The design and planning stage took a year – a lengthier process than it might have been as the initial house design was sited differently on the plot, in the back corner, where it could be orientated best for the sun. The planning application was denied and they had to start again. “That was very difficult,” Michelle acknowledges. “It was a lot of time wasted, emotional time too.”
The couple also wanted the timber-clad house to remain unpainted, but again had to compromise and paint it white. “It’s been beautifully referred to by the builders as the ‘Scout Hut’,” Michelle says, chuckling.
One of the highlights of the project was when the official airtightness check was carried out. “The whole build crew and us stood here holding our breath, watching the needle to see whether it achieved the 0.6 rating,” Michelle recalls. When it did, she says she “had to restrain myself from hugging the builder. The fact we’d reached that point of being passive; it felt like a force of will at times. But we did it, and we want other people to think, ‘we can do this too’”. k
Brennan & Wilson Architects (01368 862 783, www.bwarchitects.co.uk)