We’ve recently completed an extension/new build project on top of our office come workshop in Hackney by London Fields. The project resulted in new sustainably built office space, several flat ‘green’ roofs and a greenhouse on the second floor.
Most plants, like most people, thrive in moderate temperatures of around 18ºC to 22ºC. Conventional greenhouses tend to get too hot when the sun is shining, even in winter, and for most of the year they get too cold at night. As greenhouses have no thermal mass, that is they cannot store daytime solar gains, they have to vent surplus heat in the day and be provided with supplementary heat in the night.
Buildings by contrast, have a lot of thermal mass that can be used to store heat and release it slowly at night. This is normally lost to the night sky, but a rooftop greenhouse provides an insulating buffer, reducing heat loss while the crops growing inside gain from the transfer.
Not only has the greenhouse allowed us to grow lots of our own produce, in turn it has doubled our amount of light and halved our energy bills thanks to our clever ducting system which circulates warm air from the greenhouse to the ground floor if and when needed.