How we made a house bigger but the energy bills smaller

Bookcase House

How we made a house bigger but the energy bills smaller


SAP Energy Rating improved from E(49) to B(81)
Increase in floor area 19%
Length of bookshelves is 110 linear metres, more than that of a football pitch

A sequence of poorly planned extensions including a large conservatory had made this 1920s home in Highgate, north London, draughty to live in and expensive to run. Our clients were looking for a clear architectural strategy, a set of big ideas that would make the inside space feel more resolved, but also specific to their interests and lifestyle.

The first big idea we looked at was the possibility of demolishing the house completely and starting again from scratch. In analysis, the difference in financial cost between that and a full retrofit did not differ by much, but the cost of waste and embodied carbon was much greater. We therefore focused on taking away just the things that didn’t work – and making what remained perform better – before adding anything new.

We removed the old conservatory, and with it an awkwardly placed column in the centre of the kitchen, replacing it with an airy extension. Large in scale and framed in brick, this enables a direct visual link between the garden and the front door. With the woods rising up from the back of the garden, views from the kitchen had ended at the retaining wall; now the new extension’s high ceiling gives a connection to the sky.

This is also a house specifically tailored to family life. We were interested to discover that every fortnight the owners host a meal for at least 20 members of their extended family. Not only did the house have to be a home, it also – temporarily – had to become a restaurant. In response, the ground floor is laid out with a dining room to one side. This is not normally used but is directly linked to the cosier family dining area in the adjacent kitchen so the space can be opened out whenever needed.

Similarly, the owners had a large library, and a vision for a special place where they could curl up with a book. Around 140 linear metres of shelving have been integrated into the house, including a double height bookstack in the rear extension. This hides stairs to a mezzanine floor which has the required reading spot with its own view out over Highgate Woods.