HVAC question (1 Viewer)

Well, as people may know, I've been having a heck of a time getting someone to come out and do my HVAC work in the basement. So we got yet another quote today, this time from a company that's highly rated by Angie's List in our area.

Anyway, the guy came out (10 minutes early even!!!) and was looking at the basement. He counted the number of ducts coming off of the supply line, and said that our supply trunk was undersized. He was measuring, and said that the trunks currently start at 20" and go down to 16" (I think), and that ideally we should have 28" supply trunk!!! He said that wasn't reasonable due to space considerations, but that he'd like to make it 20" the whole way down to improve air flow.

He also wants to replace the 4 flex ducts (returns) that we have going to the living room with rigid pipe because it gives better airflow. When I mentioned that a lot of people use flex duct to keep sounds down, he said that a good rigid duct installation shouldn't add much sound and gives much better performance.

With all this, as well as adding the 3 supplies and 4 returns in the basement, he wants to charge $1,800! If we keep the flex duct returns, the cost is "only" $1,500.

Now this is MUCH higher than I was expecting to pay. However, I don't want to ruin the airflow in my house either. Is what this guy is saying correct, or is he full of crap and just trying to get a lot of money from me? Personally I'm guessing the latter, but was wondering what everyone else thought. Should I increase the size of my trunk? Is this a reasonable amount of money for that service? (they'd be expanding 10' of the return trunk and 13' of the supply trunk with this wider trunk). I'm so confused...

CW

Chris,
Without actually seeing the project, it's a tough call but....I'll go out on a limb and tell ya he's full of ****.
Keep looking, $1500-1800 is too much, IMHO.

Chris--that sounds high to me when I consider that I had a new high efficiency heatpump installed for $2400 and they added three runs and a couple of returns for no additional cost (and indicated that they would add as many as I wanted for no additional cost). Therefore, factoring in a major install of the outdoor heatpump unit and indoor airhandler with electric backup plus adding the additional runs for my future basement HT room, it would make the cost of your sheet metal work a little on the high side IMHO. However, I did choose the time of year when the HVAC companies were least busy and needing business. When I took bids based upon my specs (same airhandler, heatpump, etc.) they varied by more than $1000, which would lead me to think that additional bids might secure you a lower price IF the winter season was not keeping them so busy. Good luck.

Michael S.

WOOHOO!!!!

I just got the HVAC work done in my basement! The guy came out (Robert's Mechanical in the Twin Cities -- highly recommended) and did a very good job. He used mostly rigid duct, but did some connections with flex duct. The basement is warmer already

One thing that I thought was strange was that for the returns (at floor level), he didn't run any sort of ducts down the wall. Instead, he used some flat boards (don't recall what they're called) and said that when I put the drywall up, that the whole wall cavity acts as the return. Kinda strange, but he seemed to know what he was talking about. Can someone put my mind at ease and confirm that that's normal?

Anyway, now I have to schedule getting the electrical done. If I'm lucky, I'll have that done by the end of the month.

Things are starting to move along. Woohoo!!!

CW

PS: I got it done for $625.

ChristW--dunno what the technical trade names for the way that the area between studs is used as a cold air return, but cold air returns are commonly created that way in most homes in my area.

Michael S.

Chris,

What he did was create a plenum return within your wall cavity. While not all too common in residential installations it's very common practice in commercial buildings. The area above the drop ceilings in most office buildings is used as a plenum for return air.

One thing you may need to be aware of, though. Residential codes may differ, but in a commercial application any wires run through a plenum space must be plenum-rated. Plenum-rated wire/cable typically runs 2x-3x the cost of similar "normal" wire. If your space is to be inspected just be aware of your local codes in this regard.