The energy efficiency of the buildings sector is essential to adapt to climate change: the share of buildings in energy consumption and greenhouse gas emissions in Canada is significant.
By taking these general characteristics into consideration, it is possible to have a good overview of what is highly required and what is incidental as an intervention on a building. We can get a good idea of the main energy failures depending on the period of construction of a house. Besides, a seasoned home inspector should be able to recognize them.
For example, for older homes, there is usually a need to increase insulation and airtightness. However, relying only on increasing the insulation would greatly reduce the efficiency of the installation.
Foundation: little or none
No air barrier system.
Inefficient and polluting central oil-fired system.
Foundation: R12 by 24 inches high.
Use of polythene film.
No air exchanger, but an airtight building.
Basement slab: R5
Very good airtightness.
Mandatory air exchanger.
In Quebec, the Regulation regarding energy saving in buildings, commonly known as "Law 9" establishes minimum energy performance thresholds. These regulations were adopted in 1983 in reaction to the first oil shock and only underwent minor changes in 1985 and 1992. Quebec was then a pioneer, being the first province to adopt such economic measures in the building’s regions.
Important basic concept: iit is much more profitable to save a kilowatt hour than to produce one. This means that the investment required to save a kilowatt hour is always less than that required to produce one.
Energy Efficiency: New Rules for Large Buildings
The energy efficiency of new commercial, institutional and industrial buildings is set to take a big leap forward with the entry into force, last June, of a new chapter of the Construction Code. Please note: the transitional period ends on December 27, 2021.
The result of a collaboration between the Régie du bâtiment du Québec (RBQ) and Transition Énergie Québec (TEQ), the new chapter I.1, Energy efficiency of buildings, of the Quebec Construction Code, replaces the rules that have since applied… 1983! This is an adaptation of the 2015 National Energy Code for Buildings (CNEB) to the energy context of Quebec, a province where electricity is more affordable and where fossil fuels are used much less for heating than elsewhere in the country. The provisions concerning the building envelope, lighting and mechanics are much more detailed in this new regulation than in the previous one.
The new requirements should make it possible to improve the energy performance of new buildings by 27.9% on average compared to current requirements, according to the RBQ.
TEQ estimates the increase in construction costs linked to these new standards at 3.5%. The organization calculates that the average period of simple return on invested capital will be 6.8 years.
“It is clear that there will be impacts on businesses, but we are in favor of the company's choice to focus on energy savings”, said Guillaume Houle, spokesperson for the Association de la construction du Quebec. Companies in the building sector will indeed have to train their staff on these new measures and their consequences. They will also have to explain to their customers why these new rules lead to an increase in construction costs.
A Renewed Vision
The new Quebec regulations are generally more daring than the 2015 CNEB. For example, although the thermal resistance required for the walls is lower, the attention paid to thermal bridges is more detailed, and the requirements in matter of heat recovery are superior.
This adaptation of the CNEB is also distinguished by its way of considering the energy performance of a building as a whole and of evaluating it other than by adding the coefficients of each component, underlines the architect specializing in envelopes Richard Trempe. “The modeling part has been completely revised, “he emphasizes. We see energy efficiency globally, including building mechanics.”
Compliance with the requirements can be achieved using one of these three methods:
- The prescriptive method, which consists of following the requirements of the regulation or the proposed assembly diagrams;
- The alternative solutions method, which consists of proposing materials or assemblies equivalent to the prescriptive requirements;
- The energy performance method, that is to say the realization of a computerized energy simulation on the whole building.
Insulation and thermal bridges
The thermal resistance required for walls, roofs, floors and slabs (see table below) increases almost double. This is essentially a catch-up on part 11, “Energy efficiency,” of the Building chapter of the Quebec Construction Code, in force since 2012 in the small residential sector.
The reason why we are satisfied with RSI 3.6 (R20) for wall insulation is because it is now a question of total effective resistance rather than total thermal resistance. "We consider the best value of the wall, that of the insulation, and also the worst value, that of the framework," explains Simon Lortie, coordinator, regulations and standardization at TEQ.
Rather than imposing additional thicknesses of insulation in the walls, the new regulation requires better assemblies of materials to insulate thermal bridges, whether on a fire wall, a structural beam, a projection or a slab. Balcony.
Doors and Windows
doors with windows at 2.0. Products that achieve this coefficient are already widely offered on the market. They do not have to be Energy Star qualified.
The openings cannot count for more than 40% of the envelope. This requirement poses a challenge for curtain walls in large glass towers, as the opaque part of the cladding can hardly achieve the required thermal resistance.
“These buildings will have to comply by simulating [by computer the energy performance of the] building,” warns the architect of the RBQ, Nathalie Lessard, who participated in the development of the regulation. Designers will have to offer performance that goes beyond the Code’s requirements, for example through better building mechanics or the production of renewable energy. Many changes have been made to minimize the possibilities of privileges that would not bring the desired efficiency.”
Indoor and Outdoor Lighting
In order to reduce the total electricity consumption by lighting, the new regulation dictates maximum lighting power densities for each type of room. In addition, devices such as timers or photo controls must be installed in order to limit the consumption of electricity in this area. It will not be necessary to use advanced technologies or to use LEDs everywhere to achieve the required efficiency, underlines Simon Lortie.
In fact, one can also comply with the requirements through alternative solutions. In this case, one will base his proposals on the total energy consumption rather than on the power density of each light fixture.
The regulations also affect swimming pools, refrigeration equipment and commercial hoods. Equipment that makes it possible to reach these thresholds is already available on the market.
Thermal resistance required, zones 4, 5, 6 and 7A (southern Quebec)
|Requirements of the Quebec Construction Code (1983) |
|Requirements of the new chapter I.1 (2020)|
RSI value (R value)
Walls above ground
|≈ 2.38 (R-13.5)||3.60 (R-20.4)|
Walls in contact
|2,20 (R-12,5)||2,64 (R-15)|
|2,20 (R-12,5)||5,46 (R-31)|
|3,10 (R-17,6)||5,46 (R-31)|
|No requirement||RSI 1,76 (R-10)*|
* Requirement for a width of 1.2 m on the perimeter of the floors in contact with the ground, without integrated heating ducts.
Source : Régie du bâtiment du Québec, 2020.