I just purchased my first home and have a question about my brand new furnace.
Is it more efficient to run the heat/cool on AUTO or ON? It's a brand new Ducane gas furnace. I have it on auto now... and living in New England it is constantly flipping on/off. Not sure if that is more efficient or if I should leave it in ON mode?

Thanks!

It depends on how often the blower comes on when it is in the AUTO position in not many then it would be cheaper to leave it there. Other wise in the run position it will run all the time.

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Originally Posted by 8purplepeople

I just purchased my first home and have a question about my brand new furnace.
Is it more efficient to run the heat/cool on AUTO or ON? It's a brand new Ducane gas furnace. I have it on auto now... and living in New England it is constantly flipping on/off. Not sure if that is more efficient or if I should leave it in ON mode?

Thanks!

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I'm assuming the ON refers to the furnace fan. It's really expensive to run the fan all the time - unless you have cold spots ine house that need constantly moving air. Ditto for A/C. I tend to keep my furnace fan running more in the summer so as to suck cold air from the basement and recirculate it to the upper floors.

Our local library had a gadget you could attach to various electric appliances and this was how I learned how many kwh's were being sucked up by fridges, freezer, computers, pond pump, etc.

I've done mine both ways. With fan "ON" for 3 months and dident see any increase in electric bill. I guess it has a lot to do with the rates in your area

I think what I am going to say is correct

In AUTO the thermostat operates the fan

In ON the fan runs continuously 24/7/365

Running continuously is what
hvacservicetech_07 recommends

Bigsie, sorry to tell you this, but running the blower on cont. is actually better for it, the start and stop is what really wears it out. It actually doesn't cost much at all to run the fun constantly, actually I advise this to homeowners with large homes because it gives you a more even tempature throughout the house.

Running the fan doesn't cost much at all, because it is only a fan, about the same as a large ceiling fan. The compressor outside is what uses the most energy, more than half of the whole system.

I live in small Florida apartment, so mine is set to auto. This is because eventually, the air coming out of the vents will be humid, making it not as comfortable, and doesn't make a cooling effect like a ceiling fan. Also, you won't have to change the filter as often.

Biggsie, I didn't mean to undermind or insult you, I'm just speaking from experience.

Running a 3/4 horse fan, at 10 cent a KWH can add up to more than 30 dollars a month. I'm not going to give any bad ratings here, but split phase motors are very inefficient.

Yes, most engineers I have spoken to over the years say it is easier on the motor, but at 300 dollars a year operating cost you can afford to replace it every 10 years. (average life expectancy)

Running the fan continuously, as stated above, can improve even temperatures through out the home, in conjunction with good filtration, (and I don't mean a filtrete or plastic elecrostatic filter) it can improve indoor air quality. Indoor air is very poor when compared to outdoor air, even in a large metropolis.

Don't get me wrong filtrete filters work as advertised, if you only need 800 CFM for a 16" x 25" x 1" filter and you change it often enough.

Due the math, 800 watts per hour equals about 19KW per day, or 1.9 dollars per day, 57 dollars in a 30 day month.\

My 1/2 horse pond pump costs me 32 dollars a month at 8 cents per KW. I saw the spike in my bill the first month it was installed.

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Originally Posted by NorthernHeat

Running a 3/4 horse fan, at 10 cent a KWH can add up to more than 30 dollars a month. I'm not going to give any bad ratings here, but split phase motors are very inefficient.

Yes, most engineers I have spoken to over the years say it is easier on the motor, but at 300 dollars a year operating cost you can afford to replace it every 10 years. (average life expectancy)

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It's obvious that running it constantly uses more power. A blower motor won't die in 10 years, and still, most people are more than willing to pay the extra cost of running it than go through the trouble of having a technician put a new fan in.

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Originally Posted by NorthernHeat

Indoor air is very poor when compared to outdoor air, even in a large metropolis.

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Not in Los Angeles.

I see your point, Northernheat, Ive got a 1/2hp motor in my furnace and ran the thing for about 2 months due to a bad circuit board that I didn't have time to change, and my bill went up about four bucks a month, So I guess I'm basing my advice on that, of course, the bigger the motor, the more the cost. I'll step out of this one...

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Originally Posted by SuperTyphoon

It's obvious that running it constantly uses more power. A blower motor won't die in 10 years, and still, most people are more than willing to pay the extra cost of running it than go through the trouble of having a technician put a new fan in.



Not in Los Angeles.

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Where do you get your indoor air in Los Angeles?. Colorado. Sorry for being such a smart a... but it is still true in LA or anywhere else.

I see hundreds of 10 year old motors die, even in less than 10 years. What kills a motor, that runs constant, is dirt. If you are going to do this I would suggest good filtration.

Call your local fire department and ask them how many fires are started by dirty blowers, it seem to happen here about once a year.