Table 19: Unit costs to satisfy recommendations of the National WUI Guide

4.2.8 Energy Considerations

Vinyl siding and fibre board exterior cladding have similar insulation properties, with R values around 0.5 (Alaska Housing Finance Corp. 2020). For windows, where double-pane glazing is used to replace single-pane, the homeowner will enjoy energy savings of up to 40% (Natural Resources Canada 2020). The average Canadian household uses about 11,000 kWh of energy per year (Energy Rates Canada 2020), at a cost of about $0.174/kWh (Energy Hub 2020), suggesting an annual energy savings of about $770 per year. Over a 40-year life (Canadian Choice Windows and Doors 2020) at a 3% real discount rate, the energy savings amount to about $21,000. However, single-pane glazing has not been used in new Canadian construction since the middle of the 20th century, so it seems that retrofit to satisfy recommendations of the National WUI Guide will rarely substantially improve the energy efficiency of a house.

4.2.9 Cost Implications for Houses

The project team selects from the foregoing either what appears to be the most plausible candidate costs (if there is any strong reason to believe one option over another) or an average (where two or more costs seem equally plausible). Table 19 provides unit costs for new construction and retrofit. Costs are likely to change over time and perhaps between locations in Canada because of market volatility and local labour prices and availability. These costs may need to be revisited after about five years to ensure that benefit-cost ratios still seem accurate.

Table 19. Unit costs to satisfy recommendations of the National WUI Guide

Item Unit New Retrofit Delayed retrofit

Ext cladding fibre cement vs. vinyl CC1 sq ft ext wall ($2.72) $4.05(a) –Add type-X GB for CC1(FR) 45-min rated sq ft ext wall $0.75 $0.75 $0.75 Add type-X GB CC1(FR) 1-hour rated sq ft ext wall $1.12 $1.12 $1.12 Non-combustible roofing sq ft footprint – – –Enclose eaves and soffits lf $5.00 $10.00 $5.00 Non-combustible exterior entry door ea – $605 –Non-combustible garage door 9 ft ea ($165) $1,400 ($165) Non-combustible garage door 16 ft ea ($165) $1,650 ($165) Non-combustible deck and ground cover sq ft $15.00 $32.00 $15.00 Non-combustible apron in zone 1A lf – $8.00 $8.00 Vegetation control zone 1 or zones 1–2 ea $3,000 $4,000 $4,000 Vegetation control zones 1–3 ea $35,000 $35,000 $35,000 Energy savings: single to multi-pane glass Property – ($21,000) –Contractor overhead and profit Project cost +20% +20% +20%

(a) Nil if cladding replacement can be delayed until the vinyl meets the end of its useful life.