Rheem 2 stage vs modulating ?

[stvc]

Am trying to decide between the rheem RGRL classic and the RGFD prestige. Am a little confused that the 2 stage is 95% afue and the modulating prestige with a energy eff. blower is less - 93.4. Any thoughts which way to go?

[BaldLoonie]

The story we got from Rheem last month at the factory is temp rise. To get 95%, they run the furnaces cooler. More air, cooler temp. The Mod is designed for hot air, normally around 65° warmer than return air. Since they've designed this furnace to be the ultimate in comfort, they didn't want to tweak it with cooler discharge to get the extra couple of points on AFUE.

[stvc]

Thanks. that said is there any reason I should give more consideration to either one such as reliability, track record etc ?

[htrguy]

I believe all Rheem furnaces have a good track record. There is a consideration that does not come out of the AFUE directly. The electrical efficiency is not stated in the AFUE. Lower temperature rise is a result of higher blower speed. The gas burning efficiency may be higher but how many watts to get it?

[stvc]

I think I have made up my mind and am going with the modulating, less efficient but with a more efficient motor because I am also now adding AC so I figure it will help there too. Are you saying that the motor eff. is not included in the afue? Also, no one has replied with a pro or con for either unit or any other brand. Would it be safe to assume the pros on this site have no strong opinion of either one?

[BaldLoonie]

AFUE looks at gas use only. The VS motor will save on electricity any time the motor is on. That's why it boosts SEER of a system considerably. In constant fan it can use 1/10th of what a standard motor uses though at a lower airflow rate.

There are quite a few Rheem fans on here, including me. I think you will be very happy with the Mod and the touchscreen stat.

[stvc]

Thanks for the input, it's really helpful to get unbiased opinions on a purchase such as this. I'm in the construction industry but even the folks you are used to dealing with don't always shoot totally straight and in some cases not that familiar with the high eff. stuff i'm interested in. I actually ended up going with someone new on this one and looking forward to working with them. I'm sure I'll figure this out next week when it's installed but is the constant low speed fan option selectable from the tstat? I know it looks pretty cool but don't have all the details on it yet.

[docholiday]

If it means anything... I have a 90k Rheem Mod... In heating mode (low fire) the whol furnace including the blower, inducer and control pull about 80 watts. Less than a lightbulb (you also get a lifetime furnace replacement warranty, not just a heat exchanger with the mod)origanal owner of course.