HVAC -- what to do?

[Malcolm Hoar]

Situation:

Family of five in a 2500 sq ft single family home in Northern California (Bay Area).

Have central air with Carrier gas furnace and Armana air conditioner. We use the heating frequently in winter but only turn on the a/c when outside temps are exceptionally high. Both units are approx 20 years old. The existing flexible ducts are generally poor (with respect to leaks and insulation). They're not dreadful but certainly not great.

The air conditioning compressor has seized/blown and trips the breakers as soon as it's activated. Yes, I've tried replacing the capacitor, and it looks like the compressor is toast.

The existing a/c is probably beyond economical repair and the furnace must be approaching its end of life too.

Ideally, I'd rip out the whole lot and start over but I don't think we're gonna find the budget for that.

Interested to hear thoughts on how to go about developing a plan. I don't need (and can't afford) to go state of the art with this and lots of compromises will certainly be required.

Having said that, I've love to go dual zone (upstairs bedrooms versus downstairs living area) since we almost

*never* need to heat/cool both simultaneously.

I have one reputable contractor coming tomorrow which should start to give me a feel for options and prices but would welcome inputs from the good folks here.

[Colbyt]

My 15 year old AC will be replaced within the next month as soon as it is safe for the AC guy to work in the attic. I have no plans to replace the furnace at the same time. I really don't think 5 years is all that much extra time for a simple 80+ unit. I have furnaces that are 30+ years old working just fine. Now if your existing unit is a 90+ furnace, you should listen carefully to the estimates you receive. Those puppies do not last as long.

[Bill]

Check out Byrant. I think they have the most energy efficient A/C.

That would probably be more expensive, but run the numbers on energy savings over a period of years. These things can pay for themselves.

For example I bought a new refrigerator for $800 which saved $15 a month on the electric bill. That is $180 a year and not many years and it has paid for itself!

Also if it is cool in the evenings, you can get a window A/C for just the living room and not replace the central A/C at all! Or everyone sleep in the living room on the few hot nights you have...

[Malcolm Hoar]

Yeah, I just found a date installed sticker on the furnace: 1992.

It's given us no trouble so far but I'm guessing it doesn't have a whole lot of life left in it.

However, the furnace is stacked on the a/c air handler. I fear it's not going to play with a replacement air handler assuming I do have to install a completely new a/c system.

[Malcolm Hoar]

Yes, I'm seriously thinking about cooling only one room. I hate those window units but a mini-split could work in the master bedroom. The kids would happily sleep on the floor on those really hot nights.

We'll certainly be looking at efficiency and running costs. I'm assuming that energy costs will triple or quadruple in the next few years :-(

A whole-house fan is another possibility. It fits with the local climate but not so well with the property construction and layout I fear.

However, failing to fix/replace the existing central a/c will have an adverse impact on resale value of the home and that needs to be factored in as well.

[HeyBub]

Here's a couple of ideas:

1. Consider a used compressor. My 3-ton Trane (10-years old) blew during Hurricane Yikes what with the oscillating on-off power. I had a used condensing unit installed for 0. Almost two years now, and still going strong.

1. As for the ducts, you should be able to re-insulate them yourself at a considerable savings.

2. The most common failure on heating units is the heat exchanger. It turns to an orange-colored powder.

So what? I've never known anybody to die from an open gas flame. I grew up in a house that used natural gas space heaters for warmth and it didn't hurt me!

Look! A squirrel! Gotta go!

[Stormin Mormon]

He does make some sense. With people converting to R410a, there ought to be some used R-22 equipment out there. I've also dealt with a company that does new surplus. A couple times I've ordered out of state, and had a compressor trucked in. Cheaper than the local parts house.

Might be possible to replace the compressor, only. Please have the coils cleaned professionally at the same time. The tech should spray cleaner on, which should foam up, and be rinsed off with a garden hose.

[Stormin Mormon]

It may be possible to find a used outdoor unit. Or, to get a compressor only for the unit you have.

Others have, wisely, suggested window AC units to get you by. Ebay may be a source of equipment, not sure what's still out there.

Good lulck, and please let us know how it works out.

[jamesgangnc]

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You've past the expected life expectancy of both. You could just get the ac half replaced, new compressor and new A coil inside, but it's probably a better solution to replace both now. Single speed basic systems will be the most economical. Zone controls are expensive, pretty much equal to the price of two independent systems. If you are on a budget then you will not be getting zone control.

[Ed Pawlowski]

"jamesgangnc" wrote

It may also be required in order to get the energy credit. Be sure to check into rebates from utilities, state and federal energy credits available. You can find most of them on the Energy Star web site.

[trader4]

Exactly. Given the fed tax credits available, plus rebates, and state incentives that may also be only available, I think in this case the only logical thing to do is replace the whole thing.

[jamesgangnc]

I don't know about the tax credits but most of the sales incentoves are on the higher priced systems. It would be my recomendation to replace both just because the gsa furnanace is probably not long for this world either. A thorough inspect of it may reveal otherwise. Pricing wise most installed systems will cost you 2 to 3 times what the installer pays for the equipment. Just replacing the ac still requires the installer to mess around with the air handler to put a new A coil section in. Replacing the gas furnance and the A coil is not a whole lot more labor so you ought to get a bit of break as comapred to having the guy come back in 2 years to replace the gas furnance only.

[Malcolm Hoar]

Yes, so far I have:

• Had a technician confirm my diagnosis; the compressor motor is toast. Not really something that can be fixed economically.

• Got the rebate info. Mainly Federal plus a little from PG&E.

• Started to solicit estimates for a complete replacement (furnace and a/c). Also discovered that local HVAC contractors are *really* hungry for business around here! Seems like this is a good time to buy given that plus the govt credits.

• Identified the major issues with respect to the installation of a new system. In particular, the new compressor unit needs to be moved to the other side of the house in order to comply with code and not block a primary walkway. Fortunately, nothing too tricky or expensive.

• We have yet to decide whether to go with a multi-zone system. This would meet our needs well but add some cost. However, it seems that the incremental costs are significantly lower than they were last year, so it may be feasible.

[jamesgangnc]

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Based on other quotes I've seen I'd also ask for a two system quote if you are considering zoning. The two smaller system solution also gives you partial ac/heat when one is broken.

[Malcolm Hoar]

Yep, got all of the rebate paperwork.

Also multiple quotes. Normally, I would toss the lowest one but am probably going to make an exception in this case.

The contractor is specifying all new Trane equipment. He did a great job with a similar installation in the house next door and has other excellent references. I've checked his license with the State (all in order) and his standing with the BBB (A+).

However, I am taking some time to document my understanding and expectations with respect to the scope of the work so that no small details are overlooked.

I have also decided against zoning. It pushes up the initial cost quite a bit (although the premium is less than it was a year or two ago). I'll probably be tempted to run a zoned system far more frequently and so it will likely end up costing more in monthly running costs too.

Fortunately, the contractors who have looked at my existing duct work seem to feel it's in pretty decent shape; good for at least another 5-10 years.