Hello,
We live in a condo in the northeast on the 2 & 3 floors with a forced hot air furnace/AC in the basement. We never seem to get enough air moving up to that third floor from the AC. We had a HVAC contractor out here once who essentially said that the problem was that we need more return capacity so that we could increase the amount of air to that third floor. Currently, the only return is located in the entry stairwell down on the 1st floor. Great location for heating, but obviously not AC.
The problem with putting a return up on the third floor is that we have do go through our downstairs neighbor to do it. We do however have a chimney that is unused, and will actually be taken down and roofed over in the near future. Would it be possible (and a good or bad idea) to run a return down through that chimney. That is, without taking it apart all the way to the basement?
If that’s not a good idea… any other suggestions? We get an enormous amount of air coming out on the 2nd floor, but even shutting down all the dampers we just can’t push the air up. I thought about getting one of those in-duct fans… but the posts here seem pretty unanimously against that!
Thanks!
– kristian
Replies
Once you take the chimney down it isn't a chimney anymore only a chase which could be used for anything provided it meets fire code especially in a condo.
I would seriously look into ductless air conditioning for your situation which might solve your problem. Getting a/c into a second floor is bad enough (cold air is heavier) so a third floor would be nigh impossible unless the whole system was specifically designed and I can guarantee that it wasn't.(That cost would proabably be more than double the entire HVAC cost).
We used to say that ductless was "location specific" in that it would solve a lot of location specific problems which you definitly have.
roger
Thanks for the respone. We had looked into ductless briefly, but the HVAC guy said we would need 2 units (or at least a 2-headed unit) which would run us about $6k installed... and that a whole second system up in the attic (AC + ductwork) would be like $7000. Still cheaper to go ductless, but I was surprised at how close in price the two were. Does that seem right?
Those ductless systems are expensive and are half the price in Central America and in Asia. Someone is making huge bucks on these and the local dealer is making his also but the price for a doppleganger seems close. Shop around.
Unless someone designed (and I really mean design, like engineer stamped responsible design) I wouldn't go with any add-on ductwork that you HOPE will work. Just think how complicated a system that you would need to get enough fan oomph to push up three floors and not blow the wall paper off the wall on the first floor. You can move more air also with volume but again, complicated.
A stand alone system for a/c (why not get a heat pump system, not much more..........or shouldn't be) would give you much better control of the temp and its operation and it WILL work and you will be impressed with it.
roger
You wouldn't want to run air through the old flue liner -- too much dust, soot, and odors. But it would likely be possible to thread some flex duct (or even rigid duct, if the flue is straight enough) down through there so that the air doesn't contact the flue liner.
Hard to say if this would be enough volume, though, to make a difference. You'd likely be looking at about a 6" round.
If the chimney were completely removed then you'd have a nice chase for ductwork, but removing the chimney would likely disrupt the apartment below.
Another way to address your problem would be to extend the duct connected to the 2nd floor return up to the 3rd. One could even insert dampers to turn off (part way) the 2nd floor return.