Actual Contract cost of building the Crawfordsburn Passivhaus
One of the most commonly asked questions around Passivhaus is the cost. The Crawfordsburn Passive house was constructed at a time of recession and was a competitive contract price. The building was also 'value engineered' before it when to tender so that there were no additional costly items that were not required.
The dwelling has total area of 220.6sqm/2375sqft. The figures below are a breakdown of the construction costs, including site works, building envelope and fixtures and fittings.
Drainage - £7,000
Siteworks including paving, water trap, and lawns - £4,000
Excavation, oversite, reduced levels, foundation trenches and disposal - £980
Trenches for Mains Water supply and NIE supply - £3,000
Concrete in Foundations - £5,154
Ground Floor Construction to include: Screed, insulation, subfloor, 200mm Platinum EPS Floor insulation, foam glass perinsul SL - £6,550
Timber Frame Construction to include: External walls: U-Value of 0.11 W/(m2K) or below. To include breathable membrane, Insulated panels; vapour/airtight membrane and to include all airtightness seals/tapes Upper Floor: eco joists @400cc to incorporate services.
Roof: U-Value of 0.13W/(m2K) or below. Internal Walls (load bearing and non load bearing) Cavity Wall Ties: suitable for timber framed structures with 50mm cavity Fixing: all nails, screws and fixings Additional: 8mm plywood backing behind plasterboard -£56,000
External Outer-Leaf Construction to include:100mm concrete blockwork - £6,972
External Walls Finish to include: 10mm first undercoat, 20mm top coat, 2 coats of paint -£5,420
Windows (including Velux) and external doors - £11,220
Roof construction to include: Natural slate, Ridge tiles, Dormer roofs (zinc) - £9,221
External Zinc - £2,850
Roof drainage - £1,200
External Porch and Balcony Construction
External Porch to include: Roof construction, foundations, steel support, timber slats, flange channels, lead flashings - £2,950
External Juliet Balconies to include: Toughened glass and fixings -£1,000
Plastered internal walls and ceilings -£8,200
Internal painting -£3,000
Internal screen - £240
Staircase and internal Balconies - £4,100
Doors and frames - £5,000
Ironmongery - £500
Skirting, window boards -£1,300
Floor finishes - £2,600
Internal bookcase - £1,400
Services and Fittings
Bathroom Fittings - £200
Electrical installation - £4,200
Mechanical Ventilation Heat Recovery (MVHR) - £6,500
Plumbing and Heating Installation to include heat pump, solar panels and wood burning stove - £13,683
Subtotal - £174,440
Other associated costs (preliminaries, insurance, warranties) - £17,560
Total construction cost - £192,000
Cost comparison - Passivhaus v Standard Construction
This cost comparison exercise between Passivhaus Standard and house constructed to the minimum standard SAP 2009.
The Crawfordsburn passive house is to be 221spm. We have calculated the construction costs of an equivalent ‘typically constructed’ dwelling of a similar size, 221sqm, for comparison.
Cost is undeniably the main factor in any build. This is the limitation which determines what can be afforded, and what cannot. It is interesting for us to list the costs of our passive house, but it is useless if we have nothing to compare it too.
Total construction costs broken down into building element
Passivhaus compared to SAP 2009
£5,154 - £3,747
Ground floor construction
£6,550 - £7,231
Timber SIP Frame- standard 'stick' built timber frame and insulation
External windows and doors
£11,220 - £10,125
£28,613 - £29,613
Plumbing and heating installation
£13,683 - £600
£6,500 - £1,000
£27,540 - £21,640
£4,200 - £4,200
£32,540 - £44,513
Total construction costs compared
£192,000.00 - £175,969.00
Additional cost of building a Passivhaus compared to a typical dwelling build to current building regulation
The cost of the Crawfordsburn passive house dwelling is 8.3% more expensive than the ‘typically constructed to SAP 2009’ dwelling. The difference in construction costs is £16,031.
While this passive house cost more to construct its running costs are significantly lower. We need to gain an understanding of how quickly the construction cost difference will be regained through utility bill savings.
Keeping domestic energy bills under control is a continual battle, with energy suppliers constantly announcing price increases (energy prices have increased by over 30% over the past three years, 17.8% in this year alone). Electricity and home heating oil are typically used to fuel houses in Northern Ireland (85% of households). This innovative passive house employs a variety of techniques to fuel itself.
We have carried out exact calculations to compare the running costs of the Passivhaus with those of a conventional home. In the first year of occupation the running costs of the Passivhaus will be £414.62, considerably less than £1391.95 for a conventional dwelling. Taking into consideration the inevitable price increases the costs of running the Passivhaus are actually a minimum of 70% lower.
Payback period for Passivhaus standard
Tor the purposes of his exercise we have assumed a yearly running costs (taking into account 10% yearly electricity increase which has a compounding effect upon the larger running cost)
By year 10 our client will have gained cumulative amount of £15,575.97 in energy bill differences.
Therefore the difference of the construction cost will be regained in 10.2 years. The overall building efficiency, interior comfort levels and innovative design ensures that the Passivhaus delivers many advantages over typical construction.