Excess Furnace/AC Capacity

[Barney H.]

Even though we have only one finished room (a guest room) on the second floor of this new house, looking ahead to the time when the rest of the 2nd floor may be finished, our HVAC subcontractor put in a large furnace and AC for it, one big enough to take care of several rooms. The problem now is the noise. When it comes on, it sounds like a jet plane taking off. The subcontractor has suggested diverting a large part of the furnace/AC output into the unfinished attic space, but that will mean that most of what we pay for up there will be wasted. Can anyone suggest other solutions?

Thanks for any comments.

[Pop]

What noise? Do you mean air rushing out of the vents? The blower coming on? Both? Other? Ass-u-me it's a forced air system from your descrip.

Sending output to unused, unwanted places is, uhhhh, shall was say, STUPID? I bet that guy's union would like to hear about this, if you feel like the effort! And so especially would the BBB and your local code enforcement office. Talk to the latter; they may have some good advice for you, but you gave no hint of where you're located or even urban/suburban/exurban/non-urban. Too little information for anything definitive.

But, that is about the worst advice I've ever heard of coming from a reliable and honest contractor. Something's not cricket, either with your post or that contractor. I'd guess at this time that you have more issues than this one because it's a LOT more involved here than "extra" capacity. You were very wise to consider the extra capacity, and it's a very smart move that's cheaper today than later, but ... something's very wrong here.

I suggest another post with more details.

Pop

[TURTLE]

This is Turtle.

Tell the hvac fellow to drop the fan speed on the furnce / air handler by 1 speed. Most have a selections of 4 or more. Drop one speed till you can open up the new addition and be able to let the air flow to the other areas. Dropping one speed will not hurt a thing and they do make a lot less noise by even one speed drop.

TURTLE

[Al Bundy]

I think Turtle's advice makes a lot of sense because an over capacity AC unit won't take the humidity out as well as one sized properly because it doesn't run long enough. So the lower speed may help. This might be why the subcontractor wanted to waste some air in an unused space and he did not have your financial interest at heart.

[TURTLE]

This is Turtle.

I'm still wondering here as to why he does not want to just lower 1 speed and have more dehumitifing and just a little less air. Maybe he has a Grossly over sized unit or too small of ductwork and needs the extra air to keep it from freezing. There is something he is not letting out here for some reason or the other.

TURTLE