Central Air Replacement

[Admiral]

Ok, for all the HVAC guys, here's my question. I have a two zone system, Trane, new construction 15 years ago in 2001, I assume the builder put in the cheapest unit by the lowest bidder, and likely a SEER around 10, so anything I put in now will be more efficient. My duct work is old school uninsulated sheet metal which is not sealed very well at the joints, so likely quite a bit of leaking going on. I also have two gas furnaces for heat, so they (and the blowers) are getting old as well. In NJ, so we don't always use AC in the summer, but lately the summers are getting warmer. The units are on the way out, so I'm starting to plan. I also think I will remain in this house for the next 10 years at a minimum, and I have a bride that has incredible interest in good AC, and freaks out whenever there is a problem with them, so part of this is my own self-preservation in not wanting to have to listen to rants about the AC. Questions:

1. what are the most reliable units by manufacturer, and are there makes that are more expensive to maintain, i.e., parts are more expensive or servicing more difficult?

2. Are the makes that I should definitely avoid?

3. should I consider replacement of the furnaces (or blowers) as they are also getting old and may be inefficient as well?

4. Should I have them seal up the joints in the ducting as part of the job, or is this something I can do (it will be a real PITA), and what is the best way of doing it?

Thanks.

[rwe2156]

I would have the ducts inspected and either cleaned or replaced, then insulated.

Maybe cheaper to just put all new ducts in.

I would also have the units checked if they are working, I wouldn't replace them.

I live in the south we run AC 24/7 for 5 months of the year and most units will last 15-20 years.

[bottd]

Quality duct work is expensive, I would not replace it just because. Are you sure it leaks, often the duct sealant is placed on the inside as the pieces are assembled. If all the duct work is installed within the conditioned space and you have no problem with condensate in the summer than no worries about insulation. If in the attic or open crawl space than it should be insulated and well sealed.

If you trust consumers report their last reliability ratings had American Standard, Lennox, and Trane as the top 3, with York, Amanda, and Goodman as the bottom 3. As others have said before on here it really depends on the installation and maintenance. Properly sized, installed with correct air flow, and maintained right will go a long way in getting reliable and long life out of any equipment.

Gas furnaces last a long time - But 15 years plus means you are more than likely past the mid point and on the down hill to where they will also need replaced. If it was in the budget I would replace them with the AC units. While not absolutely necessary replacing the furnaces and the blowers will allow your contractor to match the blower to the AC unit exactly.

[Wild Turkey]

Find an established and reputable installer and ask him. When we added on contractor went with a newer contractor for a second system and we weren't happy. When time came to replace it we went back to original contractor, still in business, and are much happier.

It may cost a little more but the care, experience and support pays off in the long run.

[blackhat]

You called it a two zone system. Is it 2 stand alone systems in one space or is one of the systems zoned for sharing? Step one is an energy audit to determine if there are significant weaknesses in the thermal envelope and cost to rectify. After that a full heating / cooling load calculation and an assessment of any problem areas in the house that could be addressed. Duct leakage inside the thermal envelope is seldom a significant problem and sealing or insulating provide few benefits. With the info above, you can start to cost analyze the replacement options.

[Admiral]

Two standalone zones. Two furnaces, two AC units. Everything is in the basement (i.e., no attic units) with the big boxes outside of course. House is pretty well insulated and tight as far as the exterior goes, holds heat and cool very well.

[blackhat]

If you are happy with the system performance in meeting the needs of the home, sizing a new system to match your current unit outputs is viable. Start getting quotes for replacements from reputable dealers. I would recommend 2 stage high efficient furnaces with ECM blowers and enhanced filter boxes. I would insist on external surge protection for all the furnace and AC power supplies. A warmer climate than yours might justify a 2 stage or modulating AC but I question the payback of life cycle costs. You could ask locally. Start getting dealer recommendations and collecting quotes. Use my recommends above as a start state for discussion with contractors. Assess their response and bring any questions that raises back here.

[rwe2156]

I have 2 Goodman's in my office building. One I just replaced after 23 years, the other is 21 and still ticking.

My AC man told me the compressors all come from 2 or 3 manufacturers. The rest is controls and name.

He told me some companies like Trane and Carrier have proprietary parts.

[blackhat]

Almost. The quality of the tubing in the coils, and several other material choices also come into play.

[Admiral]

Thanks to all, very helpful to me.