Rosenthal HRV

HRV: Heat Recovery Ventilator

HRV Is It For Me?

Heat Recovery Ventilators (HRV's) were invented after the super-insulated home craze began, when people began getting sick because the air in their homes was not being diluted with fresh air leaking in as it does in typical homes. To be healthy, a minimum of one full change of all of a home's air every 3 hours is recommended. Some new homes only get about 1 change every 20 hours.

Cleaners and building products give off fumes that build up when fresh air can‘t get in. People breathe and the oxygen source couldn't be replentished in tight homes.

Moisture from sweat, showers, and cooking could not escape. Mold flourished. People got sick...AND...HRV's were invented.

An HRV vents air like an exhaust fan. However, before it lets the air out, it captures about 70-80% of the heat. Then, it brings in fresh air from outside, heating it with the captured heat, as shown in the diagram below.

To distribute the outdoor air to all living areas the HRV is can be connected to the heating system ductwork. This requires running the furnace fan continuously to distribute outdoor air throughout the house, increasing operating costs. However, the improvement in air quality is significant. Otherwise the HRV can be connected to a specially installed network of small-diameter outdoor air ducts.

Wet Windows?

In older homes, wet windows are often a sign of poorly insulated windows. A window replacement may be your best option. However, you may want to keep track of your indoor humidity first to see if there is a moisture problem. If your humidity is above 40% in winter, you may also need an HRV if a dehumidifier is not working for you. In a well insulated home, excess humidity can be a danger sign of gases building up and an HRV would be a good idea to prevent sick home syndrome.

A techician can help you determine what will work best for your home and must assess each home individually to see how to best install an HRV for you.

For more information, Canada has a helpful brochure. For product information, see Lennox HRV brochure (ignore ERV which is for warm climates).

Canada HRV Brochure Lennox HRV Brochure