My townhouse has a downflow 1994 Rheem 2.5 ton HVAC unit on its roof (combines both A/C and heat). We have had two issues with the unit and have been in the townhouse for a little under two years. In this latest case, the contractor noticed there was a crack in the heat exchanger of the unit, requiring him by law to shut off the gas and electricity to the unit. His recommendation was to replace the unit completely, in that the amount of labor spent on this and future repair work would overshoot the cost of complete replacement.

I am liable to agree with the recommendation of the contractor, but wanted to ask and see if there was anything out of the ordinary I should be aware in considering the HVAC unit's replacement?

  1. Check your unit's warranty. The heat exchangers on some units are warranteed for 20 years or longer. You may be able to get at least some money from the manufacturer, or a credit toward a new unit of the same brand. They may also cover all or part of the installation labor.

  2. Find out whether there are any federal or state tax incentives that could help. A federal tax credit has been available in the last few years for improving your home's energy efficiency, and replacing an older heating unit with a higher efficiency model was one way you could qualify. I don't know if that's still available in 2012, but worth looking.

  3. Your local utility may also offer some sort of incentive for installing a high efficiency unit (not to mention the lower monthly bills).

  4. Some utilities have programs like this one, where you can save money on your electric bill by letting the utility reduce your energy usage during peak periods. (In simple language, that means they'll turn off your air conditioning for short periods on very hot days to help avoid brownouts.) This probably won't affect your choice of a new unit, but it's something that you might want to consider at the same time.

  • 1
    Great advise. There are lots of incentives out there to upgrade to energy efficient units. Your Gas utility should be a good resource for information. Feb 22 '12 at 12:24
  • I'm not the original owner of the unit, so as much as I would love the lifetime heat exchanger warranty I don't think it applies.
    – fbrereto
    Feb 22 '12 at 17:15
  • FYI (according to this page) there are no energy star federal tax credits for HVAC systems installed after 12/31/2011: energystar.gov/index.cfm?c=tax_credits.tx_index
    – fbrereto
    Feb 22 '12 at 17:19

That unit is already 18 years old which means it's approaching its end of life. Even if you did repair the heat exchanger, you'd likely have to replace it soon anyways. With old stuff, it just always seems to be one thing after another.

Assuming its not covered by warranty, then yes I think the contractors advice to replace it with a new unit is correct. The new units are likely to be quieter and more efficient than the unit your currently have.

If you still have a non-programmable thermostat, this is a good time to change it out for a new one.


The heater is up on the roof too? A crack in your heat-exchange shouldn't affect your ability to run the air-conditioning. Turn off gas to heater? Yes. Turn off power? Maybe...

It's a big expense. I would get a second opinion, just in case you are getting scammed or aren't really comfortable with the technician yet. And I'm stuck on this -- unless your heating system is up on the roof, there's no heat-exchange in the AC part of the system. I'm no expert, but even when I lived in CA, heaters were installed inside somewhere - attic, crawl-space or closet.

But that could all be trivial, compared to the main point below.

More importantly though -- I agree with Steven -- HVAC units are generally good for 20 years. It may not make sense to put anymore money into this system (especially if it's out of warranty). Definitely get at least 2 quotes before buying a new system, and definitely check out the hi-efficiency systems.

  • 1
    The unit is a single unit heater and an air conditioner. He actually had me come up on the roof and showed me the crack in the heat exchanger. I've got a picture on my phone which he took of the crack as well.
    – fbrereto
    Feb 22 '12 at 17:11
  • Oh, excellent then. Thanks for the information.
    – Mike
    Feb 22 '12 at 18:08

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