The Carrier equipment you have been quoted is top of the line and one level below. In terms of features and quality it is very good.

The prices seem high even after rebates. I think you can do better. At these prices you should be getting a Carrier 10 year labor warranty. I don't see mention of the lineset being replace. What type of filter is included?

Did anyone do a load calculation? What are the sizes of the current equipment?

Good points above. Looks like lineset is going to be replaced, which is good. I would also want a 4-5" media filter for a higher end system. I would not choose option 2. 2-stage outdoor units work best with indoor furnaces/air handlers that have a variable speed ECM blower motor, and the 59TP5 does not. If you're going with the Infinity system, you'll want to get the whole "package" -- matching Infinity indoor/outdoor units and the controller -- for best performance.

It is difficult to judge a price without seeing everything a job entails, but from here, the quotes are definitely high. Might want to get a few more quotes.

The equipment you are being quoted appears oversized, especially the furnace. Not good for comfort or efficiency, multistage equipment or not. A load calculation should be done to determine proper sizing versus just going by what is currently installed. I second the question: What size equipment is currently in place? Not uncommon to find homes with oversized equipment that may not be performing at its full capacity for various reasons, so going with the same or larger is not always the best thing to do. If going up in size, the ductwork needs to be checked to ensure it can handle the airflow required. Note however that 2-stage air conditioners and heat pumps come in full-ton sizes, so if you had a 2.5 ton system before, then a 3 ton would be appropriate. BUT if a load calculation says 2 tons is all that's needed for downstairs, then going to a 3 ton would be bad and would likely not run long enough cycles in low stage to dehumidify well.

Are you in Montgomery County, MD by any chance?

This post was edited by ryanhughes on Thu, Apr 18, 13 at 23:24

Thank you, mike and ryan, for your responses! I'm learning more about HVAC, though not enough to be dangerous yet.

mike: yes, the lineset will be replaced. I'm not sure what filter will be included, or if the tech did a load calculation. I've emailed him to ask him those questions.

The current system is 3 ton, and seems to do alright. (It gets a little hot in the late afternoon in the summer, but is great other than that.) There was a load calculation before it was installed, but I don't have any information about that.

ryan, I'm in PG county; are we "neighbors" (in the DC metro area sense)? I'm glad you commented on system 2. My husband and I were leaning towards that one, to split the difference, so to speak. Shows you what we know.

A little information that might be relevant to the cost now... The initial installation, though inspected, was almost certainly not to code. Round flexible ducting was squashed to fit between joists, resulting in restricted flow and duct leaks. The intake/exhaust pipes are sloped AWAY from the furnace, rather than slightly towards it. The draining system doesn't work, resulting in major mold problems. I forget the rest, but there's lots more. Two of the companies that came out spent all of 5 minutes looking around, and didn't identify all the problems (they did notice the incorrect slope of the pipes, though). They're basically going to swap out the system and correct the pipe slope, and their quotes are substantially less for similar systems. The guy from the company whose bids I showed was in the crawl space and at the compressor for well over half an hour, and his company gets rave reviews from more than half a dozen friends and neighbors, so we're leaning toward spending the big bucks for a proper installation. As long as it makes sense, that is...

Thanks again for helping me ask the right questions of my HVAC guy!

I find the pricing on high side.

It's difficult for me to believe you require an 80 K furnace size for 1700 sq ft even with 9 ft ceilings especially since this is ground floor system. I would want to see a load calc. Option A is overkill in my opinion both size and models. I can make several suggestions as far as less expensive alternatives both furnace and AC.

IMO

tigerdunes, I'll say "yes, please!" to your offer of suggestions, but let's wait until I hear back from the HVAC guy about whether or not he did a load calculation. I think that makes sense, right? Many thanks!

You definitely have the right goal of seeking out a proper installation. That is certainly of utmost importance for reliability, efficiency, and comfort in the long run. Best of luck and please keep us posted with anymore information/questions. I will leave you with one company recommendation (below) in case you had any plans to seek out further estimates. They service your area and do good work. They are primarily a Lennox dealer, but they can also install Carrier equipment if that's what you're interested in. And yes -- we are neighbors. Always glad to help out another Marylander.

Here is a link that might be useful: http://www.lennoxdealer.com/handcheatingandcooling/

This post was edited by ryanhughes on Fri, Apr 19, 13 at 11:12

Thanks for the dealer recommendation, ryan! I'll certainly look them up.

So I talked with the HVAC guy. He can certainly put a 4-5" media filter on the unit. I'm glad you asked about that, ryan, because we're battling mold issues.

He did not do a load calculation. He was using our current system as a sort of baseline, and was adjusting where he thought it could improve. He is happy to do a load calculation, but it takes a lot of time, so he'll charge me for it unless we go with his company. Sounds fair to me.

His estimate of our needs included the fact that all the ducting is in our large, unconditioned crawl space. There is a vent down there, which is always closed, but we're thinking we should have it open from now on, because of the aforementioned mold problem. Also, we have a lot of windows, most with no treatments. He thought that 2.5 tons would be about right for us, but we'd need to to with 2 or 3 if we want a 2-stage system, which I think we do. I told him I might ask him to bid a 2 ton/60,000BTU 2-stage system, and he thought that could possibly work for us, especially since we set our AC at about 78.

tigerdunes, would you be willing to give me some recommendations now?

Thanks so much!

Ok here's a nice system

An Infinity 60 KBTU furnace with 3 ton two stage Performance 17 AC. Would require Infinity controller.

AHRI Directory performance/ efficiency numbers with model numbers.

5631318 Active Systems PERFORMANCE 17 PURON AC CARRIER AIR CONDITIONING 24ACB736A**31 CNPH*4321A** 59*N*A060V17**14 36000 13.00 16.20 1 RCU-A-CB 263 Yes

I agree about adding a media filter box cabinet as suggested above.

When I have time later, I will give you a less expensive middle of road system.

IMO

Here is a link that might be useful: New Infinity 96 Furnace

This post was edited by tigerdunes on Fri, Apr 19, 13 at 14:15

OK

Here are two more systems both with the new Performance 96 two stage furnace. While the furnace has a high eff ECM blower motor, it is not var speed.

The first system includes the two stage Performance 17 while the second system has the single stage Performance 16 AC. Pair with the Carrier Thermidistat. Both have good numbers.

5630882 Active Systems PERFORMANCE 17 PURON AC CARRIER AIR CONDITIONING 24ACB736A**31 CNPH*4321A** 59*P5A060E17**14 36000 12.70 16.70 1 RCU-A-CB 255

4765019 Active Systems PERFORMANCE 16 PURON AC CARRIER AIR CONDITIONING 24ACC636A**30 CNPH*4321A** 59*P5A060E17**14 34200 12.70 15.50 1 RCU-A-CB 261

IMO

Here is a link that might be useful: New Performance 96 Two Stage Furnace

Wow, tigerdunes, you are so kind to provide me with such specific recommendations! My husband has his work cut out for him this weekend. (I'll be finishing the tile on the kitchen backsplash, so he's in charge of HVAC research from now on. Phew, dodged that bullet!)

The kindness evident on all the fora I've visited here is truly heartwarming. Thank you!

you mention major mold issues.
can you give us some details?

also you mention squashed ductwork,
will this be replaced?
all ductwork & returns should be mastic sealed.
not duct tape, not foil tape but a UL rated
mastic or mastic tape like Hardcast brand #1402.

as long as returns are air tight the media filter
will work well. putting a good filter on a leaky
dusty return does little.

get a couple more bids, and ask for the
good better best that your previous company
provided. load calcs are always great..and it
is just fair to pay for them if you don't use company
that did the calcs. most only do loads when you
hire them...or release the load calc to you when
hire them.

nice to see the good info you've gotten so far.
and fyi.

best of luck.

Well, tigerdunes, my husband has quite a spreadsheet made up now. He's still in the analysis phase, and one question has become clear. If we get a two-stage system, or, even better, a modulating system, why is over sizing the furnace bad for comfort or efficiency?

energy_rater_la, the company who gave the bid above will fix the squashed ductwork. The other companies, I believe, won't. We are not sure when the mold problems started, or why. There is a lot of moisture in the crawl space that is not draining properly. We're going to get a mold company out here soon to get rid of the mold. We hope to fix the underlying problem, whatever it is, before then. My brother-in-law is a home inspector, and he'll help us figure out what the problem is.

While modulating might not be as bad as a two stage furnace, why would you want to oversize and pay for BTU capacity that you don't need or will ever use?

And with a two stage furnace that is oversized, it will simply cost you more to operate. Not to mention possible comfort issues due to short cycle which can contribute to possible premature wear and tear.

Size to the load and design temps inside and out both cooling and heating with a small fudge factor if that makes you feel good.

IMO

The reason we're considering oversizing is simply the rebate. The 80K unit is not much more expensive than the 60K one, but the rebate is much better. But if it costs more to operate over the lifetime of the unit (would it?), it might not be such a great deal after all.

P.S. I meant to ask if the modulating unit would cost more to operate.