We did a serious air sealing project on our 1990 Brampton semi-detached last fall — attic bypasses, rim joists, electrical box gaskets, the works. Our energy auditor told us that improving air sealing without adding mechanical ventilation creates indoor air quality problems. We installed an HRV.
Pre-HRV situation: Our house was tested at 4.2 ACH50 before the air sealing project. After the work, we retested at 2.6 ACH50. The energy auditor said any house below 3.0 ACH50 in Ontario should have an HRV for code compliance and health reasons. Below 2.0 ACH50 it becomes essentially mandatory.
HRV selected: Lifebreath 195 MAX (195 CFM), Ontario-made, highly regarded for core efficiency and freeze protection in cold climates. The unit integrates with our existing forced-air distribution.
Installation scope:
- HRV unit mounted in the utility room
- Supply duct: fresh air from HRV teed into the cold air return upstream of the furnace
- Exhaust duct: stale air pulled from the main floor bathroom (best location for whole-house ventilation)
- Two fresh air intake ports (one for furnace combustion air, one for HRV), two exhaust ports through the rim joist area
- Digital control replacing the old bath fan switch — controls HRV normal mode, boost mode (when someone showers), and recirculate mode (winter when outdoor temperature is very cold and you only want heat exchange, not fresh air)
Installation cost: $2,800 (Lifebreath unit $1,200 supply + $1,600 labour, no permit required for replacement/new on existing forced-air).
What changed after HRV:
- CO2 levels (monitored with an Aranet4): dropped from 1,200-1,500 ppm in morning bedroom readings to 700-900 ppm
- Humidity control improved — the HRV exhausts moisture in winter, keeping the house at 35-40% RH even with humidifier running
- Condensation on windows: eliminated (previously we had moisture on the lower corners of most windows in February)
What did not change: Our heating costs actually went up slightly (we are now conditioning fresh outdoor air that previously was not being mechanically ventilated). This is expected and correct — you pay for the fresh air you breathe. The energy recovery softens it but does not eliminate the cost.