Hello All,

We are building a nearly 6000 sqft two story home for 4 occupants. A few folks in the home have big time allergies. So we want to get the ERV right. 

We are planning to use a Mitsubishi hyper heat system. We are in climate zone 4 in Nashville. 

For the ERV, our builder is suggesting an intellibalance 200 ERV for each floor (2 total). 

Questions: 

1. Can we just have the Panasonic ERV share ducts with the Mitsubishi? These variable speed systems are designed to be constantly running even at low power, so it seems like it would work fine hooking the ERV to hvac ducts and push clean outside air to its destination in each room. There would only be a marginal penalty for having the larger hvac fan running. Rather than making all duct work dedicated for ERV? I don’t really grasp the physics behind velocities, size of ducts, etc. I imagine the answer lies in there somewhere. What is the downside of this of sharing ducts? Aside from the energy penalty?

2. Does each room need its own clean air supply? I have read some of Martin’s articles, where the ducting is simpler focusing on bathrooms and large areas,  but I wonder if the size of our house with 5 bedrooms, 6 baths, makes this not feasible? 

3. Are two intellibalances, one for each floor too much? Reading on panasonic site, one intellibalance is designed for whole house, under 7000 sqft, 7 bedrooms. 

4. Wondering if I should just give in and do the zehnder? Especially if I’m using dedicated ducts and going to do every room. I don’t really hear any complaints about their system

thanks much for taking and considering.