Heat Recovery and Ventilation Systems
Home Saving Inc.
Ventilation, Energy Recovery
Heat recovery ventilation, also known as HRV, mechanical ventilation heat recovery, or MVHR, as building efficiency is improved with insulation and weather stripping; buildings are intentionally made more airtight, and consequently less well ventilated. Since all buildings require a source of fresh air, the need for HRVs has become obvious. While opening a window does provide ventilation, the building’s heat and humidity will then be lost in the winter and gained in the summer, both of which are undesirable for the indoor climate and for energy efficiency, since the building’s HVAC systems must compensate. HRV introduces fresh air to a building and improves climate control, whilst promoting efficient energy use.
The HRV is principally designed to supply a regulated exchange of fresh air to the house, while simultaneously expelling stale indoor air. This is of particular importance in a home that is too tight to do so on its own, through passive means.
At the core of the HRV unit is a heat exchanger where the airways exhausting the warm, moisture laden indoor air, flow next to the air passages bringing in outside fresh air. Typical heat recovery percentages can range from 70 to over 90 percent, depending on the unit and the controls. This is where the HRV shines in comparison to a simple exhaust fan that blows warm air directly outside.