Description

Etxea Laura eta Martin is an EnerPHit Unit certified apartment retrofit in Donostia-San Sebastián, Spain. The 88 m² home is in a 1965 building with a concrete frame and masonry infill. All the work was done from inside the flat, with no changes to the façade.

The deep energy retrofit relied on a few simple measures that can be repeated in other flats. The external walls combine 40 mm of internal wood-fibre insulation with insulation to the existing cavity, reaching U = 0.20 W/(m²K). The floor build-up includes 80 mm of wood fibre. Certified Smartwin triple-glazed windows achieve an installed Uw of 0.90 W/(m²K). The airtight layer is continuous repaired plaster, carefully detailed around the existing shafts and pipes. It reached n50 = 0.9 h⁻¹ at the first blower-door test.

An MVHR unit provides 77% effective heat recovery. Space heating comes from a 1 kW electric post-heater in the supply air. Domestic hot water is produced by a ducted air-to-water heat pump, so the gas connection could be removed.

PHPP gives a heating demand of 23 kWh/(m²a) and a renewable primary energy (PER) demand of 63 kWh/(m²a). After 18 months in the home, the owners report steady 21 °C winter temperatures, excellent air quality and electricity costs of around €600–700 a year.Architecture and PH Design: Martin Johnson – Oreka Arkitektura
Building Services: Iturri Iturgintza
PH Certification: Oliver Style – Praxis Resilient Buildings

Web iPHa: https://passivehouse-database.org/details/8056

Photos & renders: Martin Johnson – Oreka Arkitektura