Two Story Forced Air Retrofit

[stevene]

I have a split level two-story home, approximately 1700 sq. ft., with no ducting. I want to install a forced-air system with a heat pump. I will have the air handler installed in a large crawl space under the house. The lower floor will then have return and supply outlets on the floor.

What are the pros and cons of going to the attic for the upstairs and distributing the air vertically through the ceiling? As an alternate, I would prefer to use wall stacks and have the upstairs supply in the floor, but the contractors are resistant. In either case, where should the return be located for the upper floor, or can I use one common return in the entry for both floors?

Most of the energy involved is heating. The cooling will be used only occasionally.

[easybend]

If this is a heating solution mostly there is no pros by going to the attic, maybe for the contractor, but not for you.

Heat stays low, so the registers should be low. Now if the supply hot air is blowing from the floor the return has to be close to the floor as well. Try blowing the air from the outside walls towards the "center" of the floor. At the center you can have one central return (separate return for closed bedrooms would be nice as well).