I learned something about the Kingspan Lighthouse (pictured) this weekend, something that I’d completely missed when I visited it at Offsite 07 in June, where it got star billing as the first Code for Sustainable Homes Level 6 house to be completed. The Lighthouse reverses the conventional wisdom on orientation. There is only one tiny window, indicated by my arrow, facing south. The bulk of the glazing faces east, west and north. In contrast, the south face is almost covered in photovoltaics and thermal solar panels.
Why? It seems the logic is thus. The space heating requirement has been all but insulated out of the house and the free heat arriving from the sunny south just isn’t needed in the winter heating season. And in the summer, south-facing glazing just leads to a mammouth overheating problem. It is, I think, the first house in the UK that identifies summer overheating as a bigger issue than winter warming.
Now whether this novel approach proves popular with the punters remains to be seen. But Potton Homes, recently taken over by Kingspan, feel very confident that the Lighthouse design approach is going to be a winner. They are busy incorporating Lighthouse into their brochure offerings and plan a launch event at the upcoming Grand Designs show, taking place at the NEC, October 5-7.
Coincidentally, this all chimes in with a talk given by Simos Yannas of the Architectural Association last week at the Nottingham Zero Carbon Symposium. Yannas has spent much of his working life studying passive solar design and admitted that he has always been attracted to the concept. Despite this, he has recently and reluctantly come to the conclusion that massive insulation trumps passive solar everytime. If you engineer the house down to Passivhaus levels of heat loss, solar gain just ends up being a problem. It’s unpredictable and uncontrollable and there are very few days in a year when it actually makes a useful contribution to the heating load.