The true costs of a green home

1. Innovation et processus de conception (coûts additionnels : 0 $)
This category covers the preliminary stages of a project, such as setting performance objectives for the future building, integrating green strategies, and consulting with team members. Without adding direct costs to the project, these stages represent an opportunity to plan the work properly in order to limit errors during construction. This is also the time to integrate simple energy efficiency measures, such as site-optimized passive solar design, which can have a significant influence on the performance of a building and the quality of life of its occupants at no additional cost.

2. Location and connections (additional costs: $0)
This category rewards the building’s proximity to services and transport infrastructures.
It therefore favors projects in urban areas. Although the cost of land is higher in cities than in rural areas, this category adds no additional cost to the building itself. On the other hand, it can have a significant tangible impact on the environmental performance of the building and its occupants.

3. Ecological site development (additional costs: $0)
Achieving LEED Silver certification does not require any extraordinary measures in terms of landscaping. On the contrary, it favors natural landscaping, the use of native plants and ground cover, and water-permeable materials. These strategies limit the costs incurred for earthworks, and in the medium and long term, reduce maintenance costs (e.g. fertilizers, mowing, watering).

4. Water efficiency (additional costs: $0)
The reduction from 25 % to 40 % of water consumption in a home doesn’t add any additional costs, since manufacturers now offer a host of water-efficient faucets, toilets and other equipment at the same price as conventional equipment.

Instead, achieving LEED targets requires a minimum of research and analysis into the performance of plumbing fixtures. In homes equipped with water meters or an artesian well, achieving LEED objectives represents a saving in operating costs rather than an additional expense.

5. Energy and atmosphere (additional costs: $10,500)
This category is the most important in terms of the number of LEED points earned in the certification process. In northern climates, it accounts for most of the additional costs of an energy-efficient home compared to the additional costs of a traditionally built home. The efficiency of a high-performance home depends on two essential elements, that is, increased thermal resistance of the building envelope (R-factor), and greater air tightness. As an example, let’s compare a building aiming for Novoclimat 2.0 certification and capable of achieving an EnerGuide for houses rating of 80 (the minimum required for LEED certification) with a 2,500-square-foot house of the same size built to current building codes.

The following additional costs are to be expected:

• Superior thermal insulation of concrete slabs: $3,000
• Superior thermal insulation of walls: $4,000
• Upper roof thermal insulation: $500
• Air infiltration reduction: $3,000 ($1/ft²)

6. Materials and resources (additional costs: $1,500)
This category refers to the use of ecological, local and non-toxic materials, as well as the reduction of construction site waste. As with the choice of plumbing fixtures, eco-friendly insulation, structural and finishing materials can be purchased at prices similar to those of materials with a poorer environmental record. Today’s manufacturers offer a host of interesting materials, and to achieve outstanding results in this category, it’s more important to do your research than to invest additional sums. Ask your suppliers questions about the composition, provenance and manufacture of the materials. Today on the internet you’ll find many technical data sheets and a wealth of relevant information to help you make your choices. Depending on your location, you can expect to pay around $500 extra to buy local FSC (Forest Stewardship Council) certified wood, and anywhere from zero to $1,000 to ensure proper construction waste management, whether you’re a contractor or a self-builder.

7. Indoor environmental quality (additional costs: $877)
This category focuses on good air quality in the building. In a tightly sealed home, adequate ventilation is essential. The installation of a heat recovery ventilator (HRV) that distributes fresh air to each room and controls humidity levels is beneficial to the health of occupants and promotes the building’s durability by reducing the risk of condensation, which encourages mold growth. With a heat recovery rate of 60% and installed with rigid ducts, such a system represents an additional cost of $377 ($115 installation and $262 materials) for an average-sized home, compared to the installation of a lower-quality HRV required under the new Quebec Construction Code, according to Nicolas Bégin, spokesperson for the Ministry of Natural Resources.

On the other hand, the LEED program requires the installation of a basic system to mitigate the concentration of radon (a carcinogenic gas seeping from the ground) in a house. This involves installing a ventilation duct under the concrete slab and raising it up to 12″ [30 cm] above it, at a cost of no more than $300. If a radon test shows that the concentration exceeds Health Canada’s radon guideline, the duct is connected to an extractor fan to depressurize the air under the slab to reduce radon infiltration.
Finally, combustion appliances must be connected to a fresh air intake to avoid depressurizing the building when in use ($200).
In short, we estimate the extra cost of a 2,500 ft² LEED Silver and Novoclimat 2.0 certified home at around $13,400. Given that the average cost of residential construction today is $140/sq.ft., this represents an additional cost of less than 5% compared to the cost of a home built to the current building code. These costs include excavation, foundation, well, septic system, interior finishing (including garden basement) and exterior finishing.
In the next article, we’ll try to assess the economic profitability of energy-efficient construction, bearing in mind that we build green more for the sake of our health and that of the planet than for financial reasons.

Robin Gauthier-Ouellet is the owner of Écohabitations Boréales. He is the Quebec leader in LEED single-family home construction, with eight certified homes and seven more in the process of certification, as of January 24, 2014.