Inherent failure of heat exchangers in high efficiency funaces: Myth or Reality

[mixer440]

I just finished reading this interesting article (somewhat dated: http://seattletimes.com/html/homegar...087_hay01.html) that basically said that high efficiency furnace heat exchangers inherently fail due to a number of reasons, but primarily lack of regular maintenance----the labor cost of that sometimes negating the savings from the efficiency.

(Of course the exception here, which I'm ignoring, is that the DOE will soon require +90% for buyers in many locations.)


If this is even a tiny bit true, why in the world would you want a +90% versus a 80 AFUE furnace ?

[catmanacman]

not true ,although all furnaces should be properly maintained

[tipsrfine]

In Missouri, I advise homeowners to put an 80% furnace in and use the money saved to air seal & insulate their home, and/or fix their ductwork, especially natural gas customers. NG is cheap and expected to stay that way.

[LKJoel]

I was reading this article, shaking my head wondering where this guy gets his HVAC knowledge from, then I found it, last line

"Darrell Hay is a local home inspector and manages several rental properties."

Just like any new technology, condensing gas furnaces HAD growing pains, but they are long gone ad were long gone in 2007. This article is %90 unjustified paranoia and %10 facts and should not be the reason you steer clear from condensing technology.

[tipsrfine]

The article is from 2007, I believe.

[bmathews]

A 90% furnace isn't prone to failure any more than an 80% if setup and installed correctly. It does require more maintenance due to it making water when it runs, drains can get clogged up. Depending on the model of the 90%+ furnace purchased, parts can be somewhat more expensive just because there are more of them, but a higher end 80% furnace can have expensive parts on them as well. I don't particularly care for 90% in natural gas applications unless you are in areas that stay cold, I'm in Texas, so it's a waste vs. the cost. For propane, there is a savings, but if propane is what you have, you need to go dual fuel.

[motoguy128]

If anything, I'd expect little change. The HE most suspecptible to issues would be the primary HE and it's no different than the primary in an 80%. A condensing furnace for the most part is just a 80% furnace with an additional stainless steel economizing heat exchanger added to it. This gives it the benefit of lower flue gas temps so you can use PVC vent piping. THere in lies the issues. Give an installer more flexibility and they take advantage of it and you create new installation problems.

Shrot cycling and low airflow should kill a condensing furnace just as quick as an 80%'r.

[beenthere]

Why doesn't he mention all the popped crimp rings on 80% furnaces.