[Leslie22]

We are building a new home and using radiant hydronic heating with no air conditioning because it is situated on a bulkhead on Puget Sound and gets enough of a breeze in summer to keep it cool.

My question is: What is the best way to achieve excellent air flow for this house?

At the back of the house is a 40 foot high slope and the top of the house is a deck that is connected to the top of the slope by a covered bridge. You reach the house by crossing the bridge and entering the house on the deck level.

The house has three floors plus the entrance on the fourth level (the deck). The center of the house is open to the top of the entry level (45 feet high) and contains an open stairway (the opening is almost 1/4 of the space on each floor and when you add the elevator and connecting bridges on level 2 and 3 it takes up almost 1/3 of the space on each level). Two of the side walls of this area slant slightly inward towards the top so the space gets progressively smaller as you go up.

The house has approximately 2900 square feet but only 2135 square feet of radiant floor heating after you subtract the stairs, elevator, cabinet areas, and bridge walkways on two floors.

We don’t have an attic (the roof is a deck) and this will be a well insulated house with 3’x 6’ windows across the front of the building, facing the Sound (facing NW) on each floor, 2-3 (3’ x 6’) windows on the side exterior walls and small windows in the bathrooms on the back wall.

I am assuming that I will need a whole house fan(s) and according to what I’ve read so far, I need to multiply my square footage by 3 to come up with CFM, which is 8700(?), assuming I use the square footage according to outside dimensions and not taking into account the open space in the middle of the house on 2 floors.

The top of the central area has two circular skylights (18” and 36” in diameter) and I would prefer to not have a fan in that ceiling. The back wall on the Entry level (fourth floor level) of the central stairway area has floor to ceiling height windows to provide morning light.

I am assuming I need to have an air exchange at the Entry level in order to exhaust the heated air in the summer.

Any suggestions would be greatly appreciated. Thank you.

[labman]

It is hard to say where to put the fans without seeing the house. I do want to say you need to provide some way on the lower level to allow air in, screened windows, doors, or other ways.

Hot water heat may be a good choice for such a large house. Zones work better than with forced air.