Casa MaresLisbon, 2023

Casa Mares is sixty-four homes for a housing cooperative in Marvila, in eastern Lisbon, built as a masonry ground floor with seven timber floors above. The long facades face east and west, which in Lisbon means the low afternoon sun is the main thermal load, and the first design put most living rooms on the west side to catch the evening light over the river.

Before construction we ran the thermal model against a full year of measured Lisbon weather instead of a standard design day. It showed the west living rooms overheating on most summer afternoons. Deep vertical fins, 900 millimetres from the glass and angled ten degrees to the south, cut the modelled west facade heat gain by 31 percent without losing the view. Since move-in every home has carried its own meters for heat, daylight and humidity, and a fourteen-day audit compares them with the thermal twin. Two thermal bridges found at balcony edges in the first summer were sealed within a month.