Hi, we have a weekend house with a loft. As expected, the loft stays warmer in the summer and the winter. One thing I did do was relocate the loft return to a higher spot. It had been at floor level on the open stair wall. That did help, but not quite enough. We have a Rheam combination gas (lp) furnace/heat pump. I checked and did not see any dampers on the lines. I would really not want to have to go into the crawl space to make changes all the time. I did some checking and came across a site, Smarthome that advertises a control board that would create two zones. It seems pretty straight forward, but wonder if I am missing something? Seems the best way to approach the problem. I really don't want to do something like a split system for the loft. Is a two zone system possible from one on our type of system? Bart

 

A given piece of heating or cooling equipment produces a fixed btu/hr output.
This being the case, you need to move a fixed amount of air thru the equipment. If a system is zoned, you still have to move that same amount of air which means air not needed for a particular zone has to be dumped somewhere. I've never seen a zoned system which worked well. You would be far better off with a small supplemental system for the loft.

 

Thanks Grady, I'm following you, but wondering if one zone is closed wouldn't all the available air go to the open zone?

When you say small supplemental system are there different alternatives? Could I supply the existing duct work to the loft from a seperate system?

Any ideas how to get what we are looking for out of the existing system? We can close the registers in the winter time. Any way to increase the AC flow in the summer time?

 

For the sake of simplicity lets say the main area ducts carry 800 CFM (cubic feet per minute) of air & the loft 400 CFM. If you close off the loft zone, the main area MIGHT be able to handle the excess but certainly not the other way around. In the furnace you have a fan, not a compressor. Even if you could possibly get all of the air out of the ducts, the noise at the registers would be unreal. It would sound like a jet engine & blow your hat off if you got too close.

Without getting too crazy, maybe some balancing dampers where each branch comes off of the trunk duct would be in order.

 

10-4 Thanks Grady. Makes complete sense. I think I will try putting in the dampers. Surprised the contractor did not install them (well not really considering the location of the loft return). Twice a year adjustments should not be too bad. We can handle those in between period ok.