Hi,

Full disclosure: I also posted this in the Indoor air Quality forum as HRVs appear to be discussed in both forums and the forums will not allow search on HRV (too short).

I am in a 2700 sq foot house with 1900 sq feet above grade and a finished 800 sq foot basement. House has 3 bathrooms. My house is 5 years old and was installed with the 3 bathrooms connected to a central exhaust fan. The climate is Canada and very cold. The central exhaust cannot properly/efficiently remove moisture during the coldest months. I am looking to replace or supplement the exhaust with a HRV. I have had 3 certified Venmar installers quote me 3 different solutions. I am looking for comments on why these designs would be so different and what people recommend. I was hoping using certified installers would give me a consistent installation design but this was not the case.

1.) Keep Central Exhaust Fan for bathrooms (with timers) and install HRV using vemars "simplified install". This uses the furnace to exhaust and return the air with furnace fan on low speed continuous interlock with HRV. Model recommended is any of the 1.5 models preferred EKO over SOLO. Logic is this will cover air quality with HRV and peak bath humidity with higher speed exhaust fan.

2.) Replace central exhaust fan with HRV and add HRV timers to boost bathrooms for showers etc. Interlock with furnace as previous. Using Solo 1.5 or EKO 1.5 unit. Logic is that bathroom venting with HRV on low continuous meets 20 cfm min for bathroom in 62.2 specs and venmar's "partially dedicated" install is better then "simplified install"

3.) Replace central exhaust fan with HRV and add exhaust ducts to laundry (main floor) and kitchen. Use boost timers in bathrooms with interlocked furnace. Using Solo 1.5 or EKO 1.5 unit. Not sure on logic but mentioned that dampers can be used to adjust various exhaust volumes (ie low for powder room, laundry higher for bathroom with shower etc.)

Questions:
1.) What is the current thought around using the HRV to exhaust bathrooms? is this realistic assuming HRV is running on low continuous.

2.) Why would HRV makers still recommend venting laundry spaces? I am using a front load washer and the room is exhausting with the dryer. Is this really considered a high moisture source? if i don't hang laundry is this needed?

3.) How many exhaust sources can be connected to the HRV before the draw is collectively too low on each one?

Thanks in advance
Tim