Passive house examples: cost breakdown

In this day and age anyone building or extending knows that a high level of insulation and airtightness have become practically mandatory. So we thought we’d break down the costs of two very low energy projects to show you just how much price variation there can be!

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In ROI, we bring you a detached two storey designed to PassivHaus standards with a high spec finish, costing approximately €1,700 per sqm (£158 per sqft). Supplied by architectural practice MosArt, The Phoenix Centre, Block 6, Broomhall Business Park, Wicklow, County Wicklow, tel. 0404 25777, www.mosart.ie.

BUILD SPEC

House size: 300 sqm / 3,230 sqft
External walls: U-value 0.15 W/sqmK; blockwork cavity wall filled with EPS beads, plastered inside and out, total width 50.5cm.
Floor: U-value 0.119W/sqmK; build up of 100mm concrete subfloor, 300mm phenolic foam insulation, 100mm cement screed.
Roof: U-value 0.112 W/sqmK; build up of natural slates, batten & counter- batten, breathable membrane, 100mm fibreboard, 250mm cellulose insulation between rafters, airtightness membrane, 50mm mineral wool, gypsum & cellulose plasterboard 12mm.
Windows: Triple glazed, argon filled, timber alu-clad, total U-value (frame and glazing): 0.8 W/sqmK, G-value: 0.55
Solar panels (hot water): Hot water demand: 5,930 kWh/year for six person occupancy; solar will supply 46% of this demand. Type installed: Vacuum tube collectors, 8 in total, collector area 6 sqm.
Heat recovery ventilation (hrv): 91.3% efficient with average air change rate of 0.29 l/hr for total volume 750m3 (2.5m ceiling height x 301 sqm house).

BUILD COST

Professional Fees €10,000
Earthworks €25,000
Foundations and rising walls €25,000
Structural floor slab €10,000
Blockwork and superstructure €30,000
Roof construction and roof covering €45,000
Airtightness €8,000
Windows & doors €50,000
Fascia & soffit (uPVC) €12,500
First fix electrics €10,000
Insulation to floor and walls €15,000
Insulation to roof (cellulose) €5,000
External insulation to walls €11,000
Floor screed €8,500
Plastering (internal & external) €32,000
Stone cladding €10,000
Second fix electrics €15,000
Plumbing & HRV €41,000
Carpentry works to internal and external beams €12,000
Wood flooring and tiling €25,000
Kitchen and utility fit-out €27,500
Sanitaryware for bathrooms €10,000
Stairs and handrail €20,000
Painting and decorating €12,500
Rainwater goods €5,000
Utility services €5,000
Civil works/external drainage (septic tank) €20,000
Landscaping €10,000

Total €510,000

300713PL103
In NI, here’s a one storey detached bungalow, certified PassivHaus, built to a standard spec finish, costing approximately £67 per sqft (€720 per sqm). Supplied by builders Moffitt & Robinson, 40 Blacksessiagh Road, Omagh, County Tyrone, BT78 1SU, tel. 82243656 Mobile 07803 189303, www.moffittandrobinson.co.uk

BUILD SPEC

House size: 185 sqm / 2,000 sqft
External walls: U-value 0.125W/sqmK; timber frame construction, insulated with 340mm of fibreglass insulation with airtightness membrane, OSB sheeting, plasterboard finish inside, brick and cement render on the outside.
Floor: U-value 0.13W/sqmK; build up of 25mm polystyrene, 150mm polyurethane, 75mm concrete floor, 4mm acoustic underlay, 10mm laminated floor.
Roof: U-value 0.067 W/sqmK; insulated with 600mm of fibreglass with airtightness membrane and plasterboard finish.
Windows: Triple glazed, argon filled, uPVC, total U-value (frame and glazing): 0.8W/sqmK, G-value: 0.55
Solar panels (hot water): Vacuum tube collectors, 30 in total, collector area 3.24 sqm
Heat recovery ventilation (hrv): 90% efficient

BUILD COST

Professional fees £1,120
Foundations, rising walls and structural floor slab £9,046
Blockwork and superstructure £12,691
Roof construction & covering £21,250
Airtightness £3,080
Windows & doors £6,860
Fascia & soffit (uPVC) & rainwater goods £1,200
First fix electrics £2,500
PV panels £12,800
Solar panels (hot water) £2,400
Insulation to floor, walls and roof £9,800
Floor screed £1,800
Plastering (internal and external) £5,906
Stone cladding £941
Second fix electrics £2,600
Plumbing & HRV £6,100
Wood flooring and tiling and vinyl £4,166
Kitchen and utility fit out £4,600
Sanitaryware for bathrooms £2,774
Painting and decorating £1,605
Civil works/external drainage (septic tank) £5,385
Landscaping £8,500
Roller Doors £1,120
Stove £3,300
Internal Joinery work £4,381

Total £135,925

 

Update October 2017: A reader pointed out an error in the conversion between sqm and sqft, we’ve updated the figures to reflect 1sqm=10.7639sqft. Figures are rounded.