‘low energy house MZ’ by calderon-folch-sarsanedas arquitectes, sarrià, barcelona image © R. diaz wichmann all images courtesy of calderon-folch-sarsanedas arquitectes

spanish practice calderon-folch-sarsanedas arquitectes refurbished a 94 square-meter house built in 1918 in only 120 days, to improve its energetic and acoustic comfort. the ‘low energy house MZ’ posed three challenging parameters: it’s northeast orientation, a small budget, and the client’s need to inhabit the dwelling as soon as possible. the components of the house are prefabricated, saving money and allowing the main timber structure, facade and roof to be assembled in only a few days using a numbering system like a toy set.

the biggest changes made to the existing structure are the centrally located skylight and large sliding door connecting to the long garden. the openings provide solar gain in the winter and natural ventilation in the summer, as well as illuminate the primary space and reduce the need for artificial lighting. the walls, made from structural timber frame oriented-strand-board (OSB) panels are insulated with natural sheep wool and wood fiber boards, and integrate a dual flow ventilation system with 88% heat recovery. natural larch planks constitute the facade, while heat treated pine makes up the roof and three-ply panels compose the interior cupboards. the overall result is a ten-factor rehabilitation, lowering the residence’s energy need from 171 kwh/m2 to 17 khw/m2.

calderon folch sarsanedas arquitectes: low energy house MZ dining area image © R. diaz wichmann

calderon folch sarsanedas arquitectes: low energy house MZ glass facade separating the interior and exterior image © R. diaz wichmann

calderon folch sarsanedas arquitectes: low energy house MZ living room image © R. diaz wichmann

calderon folch sarsanedas arquitectes: low energy house MZ facade facing the garden image © pol viladoms

calderon folch sarsanedas arquitectes: low energy house MZ site plan

calderon folch sarsanedas arquitectes: low energy house MZ floor plan / level 0

calderon folch sarsanedas arquitectes: low energy house MZ floor plan / level 1

calderon folch sarsanedas arquitectes: low energy house MZ floor plan / level 2

calderon folch sarsanedas arquitectes: low energy house MZ section

calderon folch sarsanedas arquitectes: low energy house MZ detail section 1. ventilated facade with vapor barrier, sheep wool and wood fiber insulation, pine structure, water impermeable and breathable membrane, larch veneer 2. heat treated pine, wood fiber insulation, waterproof membrane 3. linoleum flooring, 80 mm thermal insulation, concrete foundation 4. low-E double-pane glass wall with argon gas infill, 58% solar gain control 5. wood beams with 3-ply floor boards