Conventional Gas Furnace Question

[Jim B. Robinson]

What year did mfg's stop producing conventional, natural-draft gas furnaces, or at least start phasing them out.

[Scott Patterson]

What year did mfg's stop producing conventional, natural-draft gas furnaces, or at least start phasing them out.

Are you talking about when they started to use induction fans?

[Jim B. Robinson]

Yes, in a way. I'm interested in when the reliance on indoor combustion and dilution air was being phased out.

[Jim Luttrall]

It is still the standard in my area. Although most furnaces are mounted in attics so are using outside air, they are not sealed combustion units.
It would take a long time to get the ROI due to the fact that I am in a predominantly cooling climate.

[Scott Patterson]

Jim B., we still use make-up combustion air from the room if it is large enough. In my home, my furnace is in the attic. In homes that have them in a room that is not large enough, they add make-up air systems like a "High-Low" vent or they use a direct vent that draws the combustion air from the exterior of the homes envelope.

[David Bell]

You will still see natural draft gas boilers, but furnaces are few and far between. The manufacturers found they could make a power vented furnace with about 1/3 less material and charge more for it. The early 90s saw the biggest change.

[Matt Fellman]

If I had to pick a time I'd say late 80's - early 90's was when the changeover took place.

[Jim B. Robinson]

Thanks for the information!
Appreciated, Jim