Brick can absorb a lot of moisture, and Nova Scotia is a damp, humid place, so adding layers outboard of brick requires careful detailing. WUFI Pro dynamic hygrothermal analyses were done on several iterations of panel designs by Will Marshall of Equilibrium Engineering. The chosen solution has the wall panel offset from the brick with a ½-inch sealed air gap, which mitigates moisture problems and also provides a buffer for dimensional discrepancies in the wall. The roof panels were shown to be vulnerable to moisture and require a non-wood sheathing, such as Densglas. Moving forward with the Larsen truss panels means the completed project will store 76 tonnes of CO2e, in addition to preventing another 57 tonnes of CO2e from being emitted had the building been demolished rather than renovated.
Three scenarios were considered for mechanical updates. The existing building is heated with fuel oil, which is common in Nova Scotia, and the building also has several older mini-split heat pumps for cooling. The least expensive option was determined to be replacing the hot water radiators in each unit with electric baseboards, but this approach had the disadvantage of being very disruptive to the tenants. The solution with the lowest energy use would have been replacing the existing boiler with an air-to-water heat pump. However, this option would have high upfront costs and high maintenance costs over time, and it would still require an additional system as backup for very low temperature days. The option that was ultimately chosen was replacing the existing oil-fired boiler with an electric boiler—neither the cheapest nor the most efficient system but enough of an efficiency improvement that the building can still achieve net zero with the addition of a rooftop PV array. Each unit will also have a new ERV installed, a concession to the requirement not to disrupt the tenants.
The combined results of the envelope and mechanical upgrades represent a 75% improvement in efficiency and will prevent 28 tonnes of CO2e from being emitted annually. The retrofit benefits the environment and the comfort and health of the occupants, as well as the finances of the owners. All of the contemplated options in the project were analyzed by Jim Nostedt of SEEFAR Analytics to understand their impacts on the total cost of building ownership over the useful life of the building. Nostedt determined that completing the proposed upgrades would result in $1.5 million in operational savings with an increase in building equity of $1.3 million over a 60-year period. While this is a long timeframe for an individual property owner, the implications are profound for owners of large portfolios of buildings.
Since completing the feasibility study the ReCover team has been engaged in raising funds to complete the pilot build. Construction costs will be partially covered by the property owners with gap funding from the provincial government; to date about half of the build costs are secured. In the meantime, preparations for construction are underway, although they have taken longer than expected. Nova Scotia, like many parts of North America, is experiencing a building boom, supply chain challenges, and a labor shortage, something that ReCover’s systematic approach ultimately aims to relieve. RSI Projects secured a fabrication space in the spring of 2021 to produce prototype panels for use on a smaller build, a garage, to test the methodology before tackling the larger multi-unit project. By late spring Rudnicki and his crew had started constructing the prototype ReCover panels for the Halifax apartment building.
The ReCover team may be small, and yet it has also been mighty. The initiative has attracted national attention from municipalities across Canada seeking strategies for achieving their climate action targets, thanks to QUEST Canada’s extensive network and resources. This attention has led to a pivot from a primarily residential focus to developing retrofit strategies for all types of municipally owned buildings. As preparations and fundraising move forward for the initial pilot build, the ReCover team is simultaneously in the early stages of feasibility studies and potential demonstration projects in Nova Scotia and other Canadian cities. Deep energy retrofits to municipal buildings present opportunities to dramatically lower GHG emissions while also reducing municipal budgets. Building types include housing, office buildings, fire and police stations, and industrial facilities. The ReCover team is working with municipal staff to identify candidate buildings: buildings with aging fossil-fuel-based mechanicals, high energy use intensity, and high energy costs that also have suitable building forms and good solar potential. Current projects in planning include senior centers, transportation facilities, and a public works building.
MURB Feasibility study Metrics
Existing EUI 149 kWh/m2a
Post-retrofit modelled performance for the pilot building
