Advice on System Replacement - Chicago Area

[Lsimon]

Until last year we've never had any repairs to our HVAC system in the 15 years we've lived here. Our system is 30 years old - original from our home's construction. GE furnace and GE Air. Only service we had was maintenance until about a year ago. Since then we've had three repairs on the air conditioning including repairs to a leaky coil, and two other recharges (one last August and one this year).

We're considering replacing the whole system, considering its age, before a major problem develops and it becomes an emergency. We're happy with our current contractor, who we've used for around 5 years or more, and have a quote from them. The dollars appear reasonable based on neighbors who've purchased similar equipment from other contrctors.

My main reason for posting here is to ask for your comments and suggestions both on to equipment selection and if there are other things I should be asking my contractor about. My biggest open decision (other than biting the bullet) s air conditioner selection. Here is what we're considering all together:

XV80 furnace (variable speed - 2 stage). Considered 90% furnace, but there are installation problems that make it impractical.

Air Conditioner - either XR13 or XL16i. I understand the XR 13 is a pretty standard, but good quality, unit. The XL16i is a little more advanced and more efficient, but also is 2 stage. I understand the 2 stage will help with dehumidification (a big item for us) as well as other comfort factors.

Trane coil unit
Chimney liner
Trane THUMD300 Humidifier
Trane XL802 Thermostat

We considered an electronic air cleaner but from my research here, and on other sites, it doesn't appear it is worthwhile since we don't have allergy issues.

Any Comments or Suggestions?
Any advice on our decision over which air conditioning unit to go for?
Anything else we should be discussing with our contractor or asking them about?

Thanks in advance for your advice. This site has been helpful already and it looks like there is a great group of knowledgeable professionals that hang out here and are kind enough to share their thoughts with each other, and with us consumers.

[skippedover]

My first suggestion, as always is, did the company do a room-by-room, window-by-window heat gain/loss analysis of your home? If the answer to that question is "Yes" the I would assume the company is reasonably professional and can be helpful in your decision making process. If the answer is "NO" then find another company because you don't have a clue as to how big the furnace and/or AC needs to be for your home in it's current condition.

A word of caution: you say you haven't had any service on your existing system in 30 years. Okay, now prepare to spend all the money you saved on maintenance and repair and then some. Your new equipment will die and early death if you try the same thing now. One of the ways the new furnaces have met the federal energy standards is to decrease the thickness of the metal in the heat exchangers. Some manufacturer's heat exchangers are built differently than others and therefore fail more frequently. A good way to minimize that potential is to properly size the furnace and after the install is completed, the tech should do a temperature rise calculation with the furnace on 2nd stage heat. If it's within the manufacture's limits, then good maintenance should keep it there. What could change it? Dirty air filters, dirty AC coil, dirty, dirty 2nd stage heat exchanger, dirty blower wheel. You stated you don't have allergies and therefore opted out of IAQ products. That's okay but if the system is 30 or more years old, I'd be willing to bet that the ducts are not sealed and therefore you're wasting money by blowing treated air into the attic or basement and/or wall cavities and out of the home. Unsealed return ducts also pull in lots of dust and dirt. So sometimes a good EAC that is maintained properly (that's not washing it in the dishwasher but rather with chemicals like cleaning an old non-self cleaning oven) can go a long way toward helping you maintain a good, clean system.

As far as the 2-stage furnace and AC are concerned, you'll not save any money on a 2-stage furnace per se but you will save with the variable speed motor. You'll also save with a 2-stage AC unit as the Trane system operates a 1/2 size compressor on 1st stage and a completely different full size compressor on 2nd stage. In both instances, additional comfort should be your main goal. Savings is just a benefit. But as I said, it's all in the toilet if you haven't had a proper load calculation done and your service company should have already done that. Our company does on for each and every replacement and/or new installation. Our Comfort Advisors carry a laptop computer with them so that as soon as the home is measured, the calculation is done before any priceing of the job. If that doesn't sound like what you've experienced, better keep looking.

[Lsimon]

A word of caution: you say you haven't had any service on your existing system in 30 years. Okay, now prepare to spend all the money you saved on maintenance and repair and then some. Your new equipment will die and early death if you try the same thing now.

Not sure what you mean by above, unless you missed where I said the only service we have had was maintenance (as opposed to repairs). We did have the system maintenance done on a regular basis - more or less.

While the contractor did do a lot of measurements and spend a while doing some calculations, he did not do a "room by room, window-by-window heat gain/loss analysis". (At least I don't think he did). Frankly, I kind of wonder how many contractors I'd have to have out here before I found one who did. That's not to say it isn't important, but I'd like to hear from some others here how often I might expect to see that done? I'm truly curious.

[chucko615]

You'll have to check out the cost difference between the 16 and 13 SEER. You'll have better comfort with the 16, but you may not get enough savings on your electric bill to pay for it in Chicago. You don't have that long of a cooling season there.