Alistair Barr, founder of Barr Gazetas architects, is well versed in making period buildings more energy efficient, picking up a sustainable building of the year award in 2016 for the practice’s ‘7 Air Street’ project, currently recognised as the most sustainable historic building in the country.

His home, a converted mews house in Belsize Park is of equal eco merit, being a naturally ventilated, air-cooled space with energy-producing solar panels on the roof. Having been in the house for a year, after buying it via The Modern House, we caught up with Alistair to see what changes he has made.

Alistair: “We had always lived in Victorian north London houses, which are great because they’re so flexible, but you never feel you can get them exactly right. Then our eldest son moved to Melbourne, and our youngest son will move out soon too, so we were almost looking for the last place, in a way. We wanted to downsize but not compromise; I think our brief was to find a quiet oasis.

“My wife and I have been married 30 odd years and this is the fifth house we’ve done up. Luckily, my wife’s father is an architect so she was used to moving house every couple of years!

“In the Victorian homes we had lived in, we’d always be fighting against the nooks and crannies. Here, because the conversion was designed in a modern way, there are sections of the house for staircases and loos, for example, and the rest of it is given to big open-plan living spaces, which is much more conducive to modern living.

“There’s about half the space we had in our previous house, where both of our sons lived, but bizarrely it feels the same size, if not bigger.

“This stable dates from around 1860 and we think it was a working mews until the 1950s or 1960s. There’s something very romantic about a mews, especially a dead-end one like this one, as it creates its only little community.

“Through my practice’s work for The Crown Estate, we design to the highest sustainable credentials. We’ve learnt a lot through that process, and I knew it was possible to meet those standards in a Conservation Area, say, like we are in here.

“My office was involved the whole way through, so this is was a collaborative effort. I think sometimes when architects do their own homes they can suffer from tunnel vision, so I was keen to get as many ideas into the mix as possible. It feels like a culmination of ideas my office had been researching for a long time.

“So, downstairs we installed a false door with a louvre behind it, which allows air to come in. It’s super-insulated, so there are no drafts in winter and then last summer, it was wonderful – we could feel the cool air coming in when we opened it, which then made its way through the house. And we installed solar panels on the rooftop terrace and a unit downstairs, which tells me that, in the last three days, only 26 per cent of our power has come from the grid. We’ve been here a year, and we reckon our bills are about 30 or 40 per cent what they would be in a similar-sized house.

“The staircase that runs continuously up the house provides perfect natural ventilation. Some houses being built at the moment, which are completely sealed, well, it’s a bit controversial of me to say this but I think they are going to lead to a whole lot of trouble – there are already examples where there is too much condensation and things like that.

“I suppose the idea of having a breeze travelling through the spaces wasn’t anti-Passivhaus but it was saying that there is a way to have an energy efficient house which doesn’t feel like its hermetically sealed.

“Typically, in an old Victorian house the problem is that they’re leaky, and hot air escapes, which means you use more energy heating it and your fuel bills go up. But modern houses are all double or triple-glazed. In the summer, you actually want to have air movement through the house.

“When I first moved to London in the 1980s I worked for a private practice that was renovating blocks of flats that Camden Council had built in the 1960s. I spent my first three years as an architect putting right the flats that Camden had built wrongly – all of them were sealed units that had condensation problems and mushrooms growing in the corner!

“Without being cynical, it’s like we’ve come round in this big circle – of course, Passivhaus houses are better, but I didn’t want to live in the sort of place you could only open the window half an inch.

“Living in a modern space like this is all about efficiency. When we moved in, we had boxes to the ceiling full of stuff we had accumulated over the years. All that clutter sort of gets absorbed in a Victorian house but moving here, where there is such an emphasis on open spaces, forced us to think about what we really loved and what we could donate to the charity shop. Moving house is a great way of organising yourself.

“I think we’ll be here for a very long time. Our friends tease us about the number of stairs but I think they are good; the older you get the more you probably should be walking upstairs!”

Alistair, how do you define modern living?
“The freedom to enjoy every individual space and feel connected, but to be private if you want to be. If you can achieve this whilst connecting with sunlight and nature then you have created an oasis.”

Is there a home on The Modern House website that has caught your eye?
“Murray Mews, 1988. Madigan and Donald combine recycled London stock bricks with high-quality interiors. It sits in a cobbled mews and I think mews living is the only way for us now.”