Crawfordsburn Diary Entry No.23 - How much did it cost?
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.
Build Cost Price Inflation for historical figures
Please note that the prices below were prepared in 2012 at the time of the tendering process for Crawfordsburn Passive House. The price of materials and labour has gone up considerably since 2012 and this should be borne in mind when using these costs for current price estimates.
The Kitchen and its appliances and the bathroom sanitary-ware fittings were provided to the contractor by our client. The total price therefore excludes these items.
External Works
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
Substructure
Concrete in Foundations - £5,154
Ground Floor Construction to include: Screed, insulation, subfloor, 200mm Platinum EPS Floor insulation, foam glass perinsul SL - £6,550
Superstructure
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
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
Internal Finishes
Plastered internal walls and ceilings -£8,200
Internal painting -£3,000
Internal screen - £240
Internal Joinery
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 fitting by contractor - £200 (supplied by client)
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
Costs Summary
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
Foundations
£5,154 - £3,747
Ground floor construction
£6,550 - £7,231
Timber SIP Frame- standard 'stick' built timber frame and insulation
£56,000 -£44,800
External windows and doors
£11,220 - £10,125
External envelope
£28,613 - £29,613
Plumbing and heating installation
£13,683 - £600
Ventilation
£6,500 - £1,000
Internal finishes
£27,540 - £21,640
Electrical
£4,200 - £4,200
Prelims/insurances/site-works etc
£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.