ERV — Independently ducted with a single supply and multiple returns?
I am looking to add an independently ducted ERV to our 20 year old home. Fortunately, I have a lot of attic space which should make it easy to set up the ERV to cover the whole house without having to hook into our HVAC system (which I would prefer not to do). However, by not hooking the ERV to the HVAC system, the fresh air being supplied into the home will not be conditioned (other than from the fairly minimal air exchange process in the ERV).
As a result, I am concerned about depositing the fresh air directly into bedrooms and living spaces, particularly in the middle of summer or the middle of winter when the fresh air may be fairly hot or cold. Although I do want to be sure that the bedrooms receive the benefit of the fresh air.
Consequently, I am considering having returns in the bedrooms and other living spaces, and then having a single supply in a centrally located point in the house. The thought being that the returns in the bedrooms and living spaces will ultimately draw in some of the fresh air that has been supplied into the home, but only after it has been conditioned or mixed with the current air in the home. I realize this is probably backwards from a typical independently ducted ERV/HRV system where there is probably only one or two returns and multiple supplies into living spaces. But it seems like this idea may work. Any feedback would be appreciated. Thanks!
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Replies
Brian,
If you install a ventilation system with an ERV and dedicated ventilation ductwork, it's unlikely that you will have comfort problems, as long as you don't aim the supply air registers at the armchair you sit in to watch TV or at the head of your bed.
I've heard that some people put the supply register in the bedroom closet, and install a louvered door on the closet. That isn't necessary -- it's usually possible to locate it somewhere in the bedroom itself, as long as it isn't aimed at the head of the bed -- but it is one solution for worried people like you.
While most people install supply registers in the living room and bedrooms, and install exhaust grilles in bathrooms, the laundry room, and sometimes the kitchen, it's possible to do what you suggest. Here is a link to an article on the concept: A New Way to Duct HRVs.
Note that this method was proposed as a way to make sure that bedrooms without any heat source get more even heat. Experience has shown that this method of ducting can't accomplish that goal. But it can be used to ventilate your house, if that's what you want to do. (I assume that your bedrooms will have a heat source, so that you aren't particularly concerned about the "cold bedroom" problem.)