It has been a while since we have last blogged. You could say a lot has happened, but that would be an understatement. A year and a half ago we were optimistic here in Manitoba about our covid numbers. The province was opening, everyone was allowed to dine indoors again, and things might be returning to normal. To put it professionally, lol.
Importance of What We Breathe
The pandemic has changed the way we think about a lot of things. Some things I hope are going to be forgotten when this is behind us, others I think we are a lot better for thinking about in more sincere ways. One very important health component of everyday life in everyday spaces is air exchanges.
We have focused on air changes and bringing fresh air into closed places because of the way the virus spreads indoors. We have realized with growing certainty that breathing the same air as everyone else inside the building puts us at higher risk. Moving forward I hope we continue to frown upon breathing in everyone else’s “speaking moistly”.
Why You Should Choose An HRV/ERV?
Here is where a proper HVAC system steps in. I won’t speak much to commercial systems, there are far smarter people than myself (like Matthew Froese) who have far more information on that than I could dream of that I suggest you get in touch with regarding commercial air changes. I mean to highlight a few important reasons to get an HRV or ERV, or better yet, a combination unit with both cores.
HRVs and ERVs both deal with the same basic question. As homes began to be built with tighter and better details, we choked out the natural ventilation that most homes get through leaky walls, doors, and windows. This natural ventilation would allow fresh air in throughout the year, and we simply burned more logs to stay warm in winters. With modern building techniques we’re able to achieve staggeringly low air change numbers in our homes. HRV’s and ERV’s work to make sure that you are in control of your air in your home, and that you get fresh air every day. They are a critical component of building a healthy home.
How Does an HRV/ERV Work?
HRVs and ERVs both exchange the stale inside air with fresh outside air. But instead of direct replacement the inside air is pushed through a core that pre-conditions the incoming air from outside. Practically how this works is that your 20 degree interior air is exhausted through small channels that intermingle with the channels bringing in the -20 incoming air from outside. Now instead of -20 degree air coming in, it’s closer to 10 degrees when it gets dumped into your furnace return air, heated the rest of the way and sent throughout the house. So you are getting fresh air, without having to just open a door in the middle of winter and heat the minus 20 air to room temperature.
But What’s The Difference Between an HRV & ERV?
Now the difference between an HRV and an ERV is that ERVs will also reclaim the energy from the moisture in the air. So in winter when it’s dry outside and properly humid inside your ERV won’t continue to dehumidify the house by releasing your moisture to the outside, and vice versa in summer your ERV won’t bring in the outdoor humidity into your home. An ERV will always move your indoor air humidity level closer to the exterior humidity level. So generally in winter it will dry your home, and in summer it will moisten your home.
Can You Eat Your Cake and Have it Too?
This is where the benefit of having both cores in an exchangeable unit like the vanee unit we spec in our builds. This gives a bit more control over humidity. For example, in a new build there’s a lot of latent moisture in all the building products. Generally it takes a good year to get all that humidity out, so having an HRV core in winter to bring dry air in, and an ERV core in summer to keep humid air out makes a lot of sense.
I’m Driving Home the Point, Pay Attention!
At the end of the day the important item here is bringing in fresh oxygen. When homes are sealed as tight as our blower door tests are showing, it is imperative to have an alternative source of bringing in fresh oxygen. HRV’s and ERV’s perform well as the lungs of the home to make sure you’re breathing in fresh air at home, and non-covid laden air in restaurants, Jets games, schools, and other public places. Make sure the spaces you spend lots of time in on a regular basis have mechanisms for providing clean air. Whether you are building a new home and the HRV is required by code, or you are doing a renovation and have the opportunity to add a unit like that, they are well worth the cost to ensure you have healthy air in your lungs!