The very modest heating requirements of a Passive House leads to a rethinking of heat distribution. In Europe, the base system is typically a fully ducted Energy Recovery Ventilator - exhaust from bathrooms and kitchen, fresh air to all other rooms. To deliver the 6,000 BTUs/hr or under 2 kW of heat in the example above, an air volume of just 150 to 200 CFM could be used. This is well within the capacity of the ERVs that are designed specifically for Passive House. In fact, the European models include an air source heat pump within the ERV. Unfortunately, there are just one or two of these units that meet the basic National and Provincial requirements for cold weather performance in Canada as outlined in the Home Ventilating Institute (HVI) test protocol. There are Canadian made ERVs with adequate airflow capacity and efficiencies above 90% Apparent Sensible Effectiveness suitable for Passive House where a simple duct heater could be added. The other rather obvious approach to Passive House heating and cooling would be the mini-split, variable refrigerant air source heat pumps that are now so common. A couple of small capacity wall mount heads or a mini-ducted version would provide all the heating and cooling required.

While Passive House continues to be a niche market, more popular in mild climates such as Vancouver, it has gained the attention of those architects looking towards the Net Zero goal for all buildings by 2030. Professional mechanical contractors will do well to recognize the passion and enthusiasm Passive House proponents have and put aside your own preconceived notions of how much insulation is enough or how to calculate payback. Passive House is a rigorous, well thought out program that allows you to provide exceptional comfort and air quality with small, premium performance equipment.

This ERV unit is Canadian made and meets Passive House expectations for high performance. It could provide adequate airflow to deliver the heating capacity needs of many Passive Houses.

This article was written by Gord Cooke, President Building Knowledge Canada and originally published in Mechanical Business, September 2018 edition.