upgrade PROJECT OVERVIEW: Building type: 142 square metre semi-detached house, built 1970. Full passive house retrofit with small porch extension to south elevation. Location: Forster Park, Salthill, Co Galway, Ireland Completion date: April 2014 Budget: €136,000 plus VAT Passive house certification: Full passive house certification achieved (ref. no. 3173) Building Energy Rating (DEAP) Before: F (387.5 kWh/m2/yr) After: A2 (42.9 kWh/m2/yr) Space heating demand (PHPP) Before: unknown After: 15.14 kWh/m2/yr Heat load (PHPP) Before: unknown After: 13 W/m2 Primary energy demand (PHPP) Before: unknown After: 84 kWh/m2/yr Measured energy consumption (after): Total heating/DHW energy consumption for first year’s occupancy was 1117.45 kWh, or 7.87 kWh/m2 – or 18.65 kWh in primary energy terms. Energy bills (after): €15.50 per month or €190 (excl. VAT, levies and standing charges) for space heat and hot water for the year. Airtightness (at 50 Pascals) Before: > 10m3/m2 After: 0.4 air changes per hour Existing ground floor Before: Uninsulated 150mm concrete floor slab (removed) After: 22mm Plywood on 25mm SW battens, on 150 mm concrete floor slab, on damp proof membrane, on 200 mm XPS insulation, on radon barier. U-value: 0.116 W/m2K including an adjustment of 0.68 Existing walls Before: 300mm plastered/rendered concrete block walls with 100mm unventilated air cavity. U-value: 1.82 W/m2K After: 180mm Webertherm mineral wool insulation and Weber-rend mineral render finish externally to existing block walls. 100mm Certainfil blown platinum bead insulation into existing cavity. U-value: 0.12 W/m2K Existing roof Before: Concrete tiles on sarking felt, on battens, on timber trusses at 600mm centres with 50mm mineral wool between ceiling joists and plasterboard ceiling. U-value: 0.78 W/m2K After: Concrete tiles on breather membrane, on battens, on timber trusses at 600mm centres with 300mm Rockwool above ceiling joists and 100mm between ceiling joists, on existing plasterboard ceiling, on Pro Clima Intelllo airtight membrane, on 25mm service cavity, on new plasterboard ceiling. U-value: 0.11 W/m2K Extension walls (small front porch): 180mm Webertherm mineral wool insulation and mineral render finish externally on 215mm aerated Quinn-Lite block with plaster finish internally. U-value: 0.15 W/m2K. Extension roof (small front porch): Single ply Sarnafil roofing on 50mm well ventilated air layer, on 200mm EPS insulation, on 100 SW joists at 600 c/c with 100mm mineral wool between, on 18mm OSB airtight layer with 25mm services cavity and plasterboard ceiling. U-value: 0.11 W/m2K Windows & doors Before: Single-glazed, aluminium framed windows and timber doors. Overall approximate U-value: 5.8 W/m2K After: Munster Joinery triple-glazed Future Proof PassiV uPVC windows and doors. Passive House Institute certified U-value (installed): 0.85 W/m2K Heating system Before: c.20 year old oil fired boiler & radiators throughout After: Thermia DHP-AQ 6.7kW air-to-water heat pump with a CoP of 4.17 feeding 210ltr Dimplex thermal store with thermostatically controlled draw-off for two radiators and a towel rail. Ventilation Before: No ventilation system. Reliant on infiltration, kitchen extractor, chimney and opening windows. After: Zehnder Comfoair 350 MVHR with a Passive House Institute certified heat recovery efficiency of 84%. Zehnder manifolds and 80mm diameter Zehnder ConfoTube flexible ductwork. Green materials: Reused concrete block walls, timber and tile roof and timber intermediate floors; 50% Ecocem GGBS cement; mineral wool insulation throughout. Zero VOC ductwork to MVHR.
(below right) The outdoor unit of the Thermia air-towater heat pump system; (above) the house’s humidity and temperature sensor; (top) deep window sills, created by the use of external insulation, provide space to display artwork; (p73, top) airtightness tapes and membranes were fitted to windows and doors, then taped to the walls on installation before being wet plastered over to ensure a total seal; (bottom, left) the ground floor was insulated with 200mm of XPS insulation; (bottom, right) the masonry walls were insulated externally with Webertherm mineral wool