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Seniors’ homes (MDA): Energy mix, the preferred solution to meet sustainable development requirements

December 10, 2021    5 min.

Announced as “a major transformation in housing environments for seniors,” the seniors’ homes project, launched by the Québec government in 2019, has the goal of creating human dimension living environments for seniors with little to moderate autonomy. Divided into modern, friendly “living units,” each accommodating 12 residents, the buildings include between 12 to 192 air-conditioning rooms.

In this ambitious project, the MDAs have to integrate best sustainable development practices, while respecting certain economic imperatives. What are the challenges that the master team (Bouthillette Parizeau) had to meet in this regard? What solutions did it propose and why? That is what we plan to find out in this case study.


Seniors’ homes in a few numbers

  • 46 buildings across the province
  • Total surface area: approx. 375,000 m2
  • 3,468 beds: average 74 beds/building
  • 1 GJ/m2 energy consumption for a total of: 375,000 GJ/year
  • Construction cost: $1.5 billion
Seniors’ home - outdoors, MDA

Overview of projects

Method used Number of buildings Number of beds
Traditional method by master team 8 672
Traditional method 25 1,836
CCF – Conception/Construction/Financing 13 960


General requirements

  • Create functional 12-room units with dedicated support spaces, as shown below in the layout of a typical floor.
  • Respect the latest instructions in the fight against pandemics: each space constitutes a protected bubble thank to ample ventilation.
  • Orient the rooms toward a living area to create a dynamic space.

Sustainable development requirements

  1. Optimize energy efficiency: + 20% above CNEB2011 (ASHRAE 90.1-2010 reference not accepted for demonstrating efficiency).
  2. Reduce GHGs: Respect criteria 2 & 3 of CCAP 2020, i.e., maximum 20% of fuel used for energy needs, 15% of total consumption.
  3. Obtain LEEDv4 Certification – Healthcare: The number of points for the Energy and atmosphere credit varies between 10 and 17, depending on the building.
  4. Respect CSAZ317.2-2015 standard, which includes specific requirements for heating, ventilation, and air-conditioning (HVAC) systems for healthcare facilities.
Seniors’ home - indoors, MDA


Master team choices

Category Choice
Lighting  Entirely LED lighting
Domestic hot water
  • Low energy consumption appliances
  • Production by electric water heaters combined with fuel-fired water heaters
  • Heat recovery on outdoor air (dedicated systems) with cassette-type regenerative heat exchangers (efficiency up to 90% sensible/75% latent)
  • Double-duct systems for households
  • Simple duct systems for behind-the-scenes sectors
  • Electric boilers combined with fuel-fired boilers (propane or natural gas, depending on availability at each MDA)
  • Radiant floor heating for households with slab on grade
  • Air-cooled outdoor chillers
  • Liquid chiller for free mid-season cooling

*Heating: Explanation of choices

Select the best energy available at the best cost

In the first drafts, an all-electric strategy was envisaged, but given the requirement for boiler redundancy in case of power outages, huge capacity generators would have been required.

Using gas-fired boilers/water heaters allows an appreciable reduction in the capacity of the generators and an average investment saving of about $4 M compared with the use of 100% electric boilers.

Besides considerably reducing capital costs, natural gas boilers also allow savings in the operating costs of managing electricity peaks.


Optimize peak management

When natural gas is available, gas-fired boilers/water heaters are used to manage electricity peaks, respecting criteria 2 & 3 of CCAP 2020.

Peak management allows a quite significant energy saving of about $5/m2, which translates into an average annual saving of $26,000 for a 48-bed MDA, $40,000 for a 72-bed MDA, and $52,000 for a 96-bed MDA. The saving comes from reducing the monthly peak and removing the applicability of the penalty imposed by Rate M.

Note: This peak management strategy is not used for buildings that use propane because of the high costs of propane compared with natural gas.


Technologies envisaged but not retained

Technology Decisions
Geothermal Too many risks are associated with the non-repeatability of the solution, which is dependent on worksite conditions and soil typologies.
Aerothermal Impracticable in a cost-management context.
Heat recovery from chillers Little potential, given the high heat recovery from exhaust air by the heat exchangers, as well as the shape of the buildings.


Solutions from the concept teams

According to the concept teams, certain variabilities can be observed on the various projects, the most important being:

  • 100% outdoor air systems with heat recovery
  • Recovery chillers
  • Heat recovery on outdoor air with lower efficiencies
  • Single duct systems with electric terminal reheat to ensure comfort

Results for a 96-bed MDA

96-bed MDA configuration 

Typical hybrid – Lebourneuf 96 beds

Typical hybrid – Lebourneuf 96 beds -eQuest

Presentation of results compared with requirements

Requirements Objectives Results or Proposal
1. Optimize energy efficiency 20% more efficient than CNEB2011 31% more efficient than CNEB2011

Sources of savings:

  • 60% saving on lighting
  • 47% saving on heating
  • 85% saving on humidification
  • 47% on domestic hot water

See below Table 4

2. Reduce GHGs  Respect criteria 2 & 3 of CCAP 2020 See below Table 5
3. Obtain LEEDv4 certification - Healthcare Between 10 and 17 points 17 points LEED v4 – Energy and atmosphere
4. Respect CSAZ317.2-2015 Standard  Respect the particular requirements of healthcare establishments
  • There is over-consumption in ventilation compared to the reference, which establishes low static pressures, has no recovery, and few fans.
  • The reference is more affected than the proposal since the electricity peak and rate penalties result in a higher equivalent cost ($/kWh).

Table 4 - Sources of energy savings

Proposal CNEB2011
Electricity Natural gas Total Electricity Natural gas Total
Lighting 883,843 - 883,843 2,185,425 - 2,185,425
Various equipment 1,966,040 - 1,966,040 1,966,040 - 1,966,040
Kitchen equipment 49,926 - 49,926 49,926 - 49,926
Heating 2,690,698 1,001,430 3,692,127 4,369,629 2,635,850 7,005,478
Air-conditioning 883,875 - 883,875 583,631 - 583,631
Pumps 457,638 - 457,638 33,084 - 33,084
Heat release - - - -
Humidification 367,299 - 367,299 2,462,185 - 2,462,185
Ventilation 2,582,497 - 2,582,497 1,247,302 - 1,247,302
Domestic hot water 732,307 732,307  - 1,392,826 1,392,826
TOTAL 9,881,815 1,733,736 11,615,552 12,897,222 4,028,676 16,925,898
Energy savings 31%
COSTS $202,884 $19,182 $222,066 $334,888 $41,793 $376,681
Cost savings 41%
Statistics Proposal CNEB2011
Surface area - m2 10,493
GJ/m2 1,11 1,61
kWh/pi2 29,22 42,58
Average cost - $/kWh 0,074 0,093
Average cost - $/m3 0,42 0,39

Table 5 - Goals related to CCAP 2020 (to be removed from table)

Objectives related to CCAP 2020 Proposal Objectifs
% of energy needs for heating met by fuel 11,8% < 20%
% of fuel consumption compared with building's total energy consumption 14, 9% < 15%

Role of Énergir in this project

Énergir participated in the MDA project by supporting the master team in seeking solutions that optimally meet requirements while maximizing the amount of financial assistance available. This collaboration led, in particular, to grants averaging $70,000 for 96-bed MDAs under the New efficient construction program.


Given a context that called for reconciling energy savings and costs, reducing GHG, and ensuring the comfort of the users, the energy mix (the right energy in the right place at the right time) turned out to be the most viable solution for the seniors’ homes. While the choice of technologies may vary according to the local setting, the combined and complementary use of natural gas and electricity will enable delivering MDAs that comply in all respects to government requirements. To date, 34 of the 46 MDAs announced are already under construction, and the large majority should be delivered by Fall 2022.

Seniors’ home - outdoors, MDA
Nathalie Boulet, Eng., CEM CEA Leed C+CB
Project Manager,
Bouthillette Parizeau
Sami Maksoud, Eng., M. Eng., MBA, CMVP®
Advisor, Energy Efficiency, DATECH

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