House Shopping 101: “Don’t worry, the City inspected it!” #7: HRV intake terminal incorrect
This is the seventh in a series on construction defects found in the Greater Toronto Area, Ontario, Canada. The header photo shows an HRV. This HRV is red and flashy and has a continuously variable transmission all wheel drive. I don’t know how Honda picked the HRV name, but HRV in the residential building world stands for heat recovery ventilator. The HRVs I want to talk about are quite boring and are tucked away in the basement where most homeowners can ignore them.
An HRV is a system that ventilates the house with fresh air and recovers heat from outgoing air. There is also a similar system called an ERV (Energy Recovery Ventilator) that recovers heat from the air and heat from moisture in the air. Photo at left shows a typical HRV installation. In this photo the front cover of the box is open. Note the two insulated hoses at the left. Those are the two hoses that connect to the exterior.
Most new high-rise condominium units are now equipped with ERVS, often integrated with the bathroom exhaust system. Some houses built in the 90s and 2000s may have an HRV installed, but until now, HRVs were not that common. Many houses built since 2012 have HRVs installed as part of the builder’s energy compliance package options.
HRVs (and ERVs) have two connections to outside air. One is an intake and one is an exhaust. The exterior terminals are easy to find because they are quite large and close to the ground. The exception is on townhouse units where the terminals may be higher up and may be in the form of a single concentric combination intake/exhaust terminal.
A common defect I find related to HRVs is installation of the incorrect type of intake terminal at the exterior. The intake must be an “always open” type terminal with fixed louvers and a screen.
This photo shows an HRV intake terminal that is correct. It is an “always open” terminal with a screen. The paper is being drawn in against the terminal when the HRV is in operation.
This photo shows an HRV intake equipped with the incorrect terminal. The terminal is designed as an exhaust terminal. It has louvers that will open when air is blowing outwards. When this type of exhaust terminal is installed as an intake terminal for an HRV, it slams shut and no air can flow inwards. It’s never a good idea to violate the code of common sense. Unfortunately, there is no indication to the homeowner that the HRV intake is blocked. The HRV will continue to run without any sort of warning. I have found the incorrect terminal installed on a 10 year- old house. For 10 years the HRV intake had been “dead heading” and not bringing in any outside air.
It’s a common sounding from the selling parties on new or almost new homes. Especially those built without Tarion warranty. “Don’t worry, the City inspected it”. As an inspector serving the buying community, I am often amused by that statement. My income on new and nearly new home inspections relies directly on identifying the leftover issues after all the builder and municipal inspections are complete and the first owner has taken possession. These issues don’t go away on their own, and I also find “builder issues” on resale homes, even up to 50 years after original construction.
Don’t hesitate to have new or nearly-new homes inspected by a professional.