You have already posted this question several days ago. No need to repost. This is poor forum etiquette. Keep all posts within one thread. This helps all who are interested to follow your thread.

So sorry, tigerdunes, I didn't mean to be rude. I appreciated your previous answer, I just wasn't sure my reply would be seen. Also, we narrowed down our choice, but are still trying to figure this out, so thought a new post would be in order.

Depends on the load of the home. Where it is located etc etc.

You are welcome. HVAC-consult.com

We decided to go with the single stage furnace. Our home is a 1500 sq. ft. ranch in the midwest. We've always had single stage furnaces and have been comfortable with them. I'm happy with the 96% efficiency rating on it. We sort of feel like there's no sense in trying to "reinvent the wheel". And, we're happy to save some $ too. Thank you for your responses. They were much appreciated!

Hope you get sized correctly....60 K or 80 K?...I see nothing wring with a single stage but you do want a high eff blower motor...plus media filter cabinet if you don't already have one...both well worth it...

tigerdunes, the hvac co. did a load calculation, and it came in at 80 K. It has a multi-speed blower. We already have the media filter cabinet, so I think we're good to go. We chose a company with an excellent reputation in our area, so are sure it will be installed correctly. Thanks for your help!

an 80 K for 1500 sq ft?...simply ridiculous...is blower motor high efficient or just conventional?...you are getting ready to make a mistake on the sizing...

IMO

Multi-speed does not necessarily mean variable speed. It sometimes means that the installer has multiple options for selecting a single fixed speed at installation.

I would first advise you to ignore AFUE. Condensing is condensing. Look at your gas utility rate. Multiply your per therm rate by .06. That is the cost savings of a barely condensing 90% vs a 96%.

Next, consider the two-stage difference of input and blower type. The biggest cost in operating a furnace is the electricity that a fan uses. At low-stage the fan speed is much lower, thus the electricity savings is much greater. A variable speed furnace uses a ECM motor, which is inherently much more efficient than an AC motor that fixed-speed models use.

Finally, consider how appliances work. A two-stage unit means that it will run lower longer. You want your equipment to run at low speed for as long as possible with as high of a setpoint delta as you can tolerate. That means the equipment will cycle less. Cycling is what determines an equipment's lifespan. The more cycles you add, the closer you are getting to the end of its' life.

There is a comfort aspect to it too, but that is subjective.

"The biggest cost in operating a furnace is the electricity that a fan uses. "

I think your math is waay off. Read Mike's description above for what a multistage system offers. He prefers them, I personally don't but i also don't live in a humid summer climate. If I did, I might share his view.

Here's an example for the money calculation. -

My furnace's blower seems to be between 500-600 watts. Let's be generous and round it up to 1000 watts. Operating for one hour would be 1 kilowatt hour, which at my top tiered rate is 30 cents. Remember we rounded up. And in most parts of the US, this number averages about 15 cents and can be much less.

My furnace is 120K btu/hr, input. Let's round that DOWN to 100K btu/hr. At the top tier, I pay over $1.50 per therm (which is 100 btus) but lets round that down too to $1.20.

Operating my furnace for one hour costs $1.20 for gas, 30 cents for electricity. The real electricity number is less because I rounded up, and the real gas number is more because i rounded down.

Did I get something wrong?

I agree with your math. My assumption is that they'd have a fan coil on top of that furnace. You only have to pay for gas during heating, while you have to pay for the blower electricity year round. If you only have a furnace, then I'd agree that there is no payback on the fan. When you add items like a coil, HEPA filter, continuous fan mode, high static duct work, etc, then I stand by the fan watts being far more important than the gas consumption. Also, the motor isn't a "little more efficient" as stated before. An ECM is 20%-30% more efficient at the motor level than a PSC, and qualifies for utility rebates in some states.

Hold on.

When running in A/C mode, the condenser is going to be gobbling many kilowatt hours of electricity each hour while the fan is still just consuming some hundreds of watts per hour. An hour of A/C can be more expensive than an hour of heat.

The consumption of the equipment to heat OR cool the air passing through the system can cost 5-10 X as much as the cost to run the fan. That's where the money is, not so much the fan.

In the end, we chose the Amana single stage furnace. It has 96% AFUE. The multi-speed blower, as I understand it, comes on lower upon starting, then goes higher when the air is warmer. We chose this because it is "tried and true" and we just didn't want to spend an extra grand for added features that we've lived without our whole lives. Capedude, we do have central air, so I guess that would increase electricity cost not having the ECM, but, it only runs about 3 months out of the year. Hopefully, this furnace will be a good one. So far, (had it about a week, now) we're very happy with it. Thanks everyone for taking the time to offer your advice/opinions. I appreciate all of them!