Which uses more electricity, furnace blower or portable heater?


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Old 01-16-07, 03:46 PM
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Which uses more electricity, furnace blower or portable heater?

Our finished basement gets cool in the winter. I purchased an oil filled portable heater (DeLonghi) to help supplement the furnace heat. It helps quite a bit when on, but the thing uses 1500W of power on high (other available settings are 700W and 900W). I have also read that leaving the furnace blower set to "on" all the time will help even out the temperature so that the basement will feel warmer.

Given the choice of 1) setting the blower to "on" or 2) using a 1500W setting on the portable heater, which will have the least impact on my electric bill? I can't find a wattage rating on my furnace blower, but I'm pretty sure it's fairly average in size (installed for an 1800 sqft atrium ranch home). I realize there are other considerations such as wear and tear on the blower motor and overall comfort level between the two options, but I'm mainly interested in electricity usage.

Also, how do I calculate the dollar impact on my monthly electric bill of running the 1500W heater for say 10 hours a day at some assumed electric rate? I think the rates are based on KWH, but I need to check a recent bill. Is it as simple as 10 Hours X 1.5KW per Hour X Rate?

EDIT: I think I figured this out - I think it's about $30/month (1.5KW * 10 hrs per day * .065$/KWH * 30days). Now I just need to know how many watts a "typical" furnace blower uses...15amp * 120V = 1800W???

Any help or opinions would be appreciated.

Thanks,
Nuzy
 

Last edited by Nuzy; 01-16-07 at 04:01 PM. Reason: answered own cost question
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Old 01-17-07, 11:54 AM
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Wink

Look on the blower motor name plate. It will have the AMP draw for that motor on it.
 
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Old 01-17-07, 01:46 PM
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Thanks, Ed. I'll take a look when I get home.

Any opinion or experience on which will give me more comfort level in the basement, running the blower vs. running the portable heater?

Also, will running the blower constantly have significant wear and tear on the blower or is it negligable given the overall life of the blower.

Thanks again!
 
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Old 01-17-07, 01:57 PM
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Wink

More heat right where you need it is best in the long run. BUT not sure just what all you have there its hard to say for sure.
On many homes we say run the blower 24/7. The blower is a lot the same as the AC. It costs a lot more to start and stop and start it. Than to just let them run.
 
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Old 01-17-07, 06:53 PM
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Is your furnace newer or older? Standard or Variable speed? Do you have any returns in the basement? Where are the supply vents?

I run our fan all the time in the winter, and our temps are same as upstairs (68degrees).. In the summer I leave it in Auto in the day and Circ at night.

I think over all, your heater is going to cost more to run than running the fan.
 
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Old 01-17-07, 09:41 PM
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Jay,

It's a newer furnace, only about 4 yrs old. Nordyne 96000 btuh, 1/2 hp motor. Manual says multi-speed motor: High (factory preset cooling speed), Med-High, Med-Low (factory preset heating speed), Low. Manual also says my model has max operating voltage 127, minimum 103, and max amperes is 9. So I guess worst case it's around 1100W vs the 1500W portable heater. I should have dug the manual out earlier!

There are no returns in the basement because it's an atrium ranch. We had five different contractors bid on the basement job and they all told us that since the air is free to flow up through the large open stairwell at the back of the house and to the return vents upstairs, they really did not need to put in any return ducts downstairs. The staircase is open and on the back wall of the house where all the windows are located. There also is a full louvered door going into the storage room where the furnace is located.

The basement supply vents are located towards the front of the house in the ceiling blowing down. In theory, the warm air should be pulled across the basement from the supply vents in the front to the back where the windows are located and up the open stairwell to the returns on the main level - at least I think that was the idea when it was done. When the heat is on, it's pretty comfortable, but when it turns off it gets cool down there. In reality, since heat rises, I think it's mostly just going upstairs rather than staying downstairs, but I guess there really isn't much that can be done about that - maybe that is where turning the blower to "on" would help?

We keep the upstairs at 68 degrees too. I would guess that downstairs is probably several degrees cooler - enough that it is noticable when the furnace is not pumping warm air down there. I'll have to put a thermometer down here and get a real check with and without the blower on to see how much difference it makes.

Thanks for the input.
Mike
 
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Old 01-18-07, 06:37 AM
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I still would of put a return in down there. Cold air falls, and with that large stairway, the cold air upstairs is going to "roll down" the steps to the basement.

do you have central air?

Try the fan ON for a few days and see what you think?
 
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Old 01-18-07, 07:29 AM
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Yeah, I should have forced the issue when I had the chance. Maybe that would have helped pull the warm air from downstairs too, or keep the warm air downstairs from going upstairs. Not too much I can do about that now, although I may see if there is a way to tap into the return duct from the unfinished storage area into the finished area. I'll try the fan for a couple days and see if that helps. It's not unbearable, just not a perfect balance.

Yes, we do have central air. In the summer I shut off all the vents in the basement, because it keeps itself nice and cool. Of course, as you said, there's probably quite a bit of my conditioned air falling down into the basement from upstairs, which is why it can be much warmer upstairs in the summer. I think there is more of a temp difference between the two floors in the summer than in the winter.

Thanks again,
Mike
 
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Old 01-22-07, 03:47 PM
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Just thought I'd kind of close the loop on this. It turns out that keeping the blower on during the day rather than setting it to auto makes a pretty big difference with respect to keeping the temperature more even throughout the house. As a matter of fact, when I go downstairs after work when it's been running all day I barely notice much difference in temperature from upstairs.

I've decided to keep the fan on during the day when the wife and kids are home and turn it back to auto when we go to bed - I'll reverse this in the summer. I'll use the oil-filled electric heater when it gets really cold outside and we need the supplemental heat downstairs. This shouldn't add more than about $20/mth to my electric bill and only for 6 or so months out of the year. I think this is the most optimal / efficient method for me in terms of cost vs. comfort.

Thanks for the suggestions and help.
Mike
 
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Old 01-22-07, 04:03 PM
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Glad to hear that you do notice that it helps to keep the fan on.

If you get to the point where you don't like switching the fan and off all the time. Upgrade to a new t-stat like Honeywell VisionPro. You can program the blower to come on, or to Auto, or to Circ.

I have the above t-stat, and I program mine to do the stuff below.

-7am 68, fan ON
-8am 60, fan ON
-5pm 68, fan ON
-10pm 60, Fan Circ

Summer, I leave the temp at 76 at all times, and only run fan in AUTO in the day, and Circ at night.
 
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Old 01-22-07, 07:57 PM
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Thanks for the suggestion. I never really saw the need for a programmable thermostat since the wife and kids were home all day and the only time I changed temp was before we went to bed and when we got up. Now that I will be using the fan, I'll check into the one you suggested. It would be much more convenient. I didn't realize a t-stat could turn the fan on and off. I thought it just changed the temperature setting at specific times.

By the way, what is the "circ" mode? When you mentioned circ, I thought you were using it to mean "on." It appears that they are two different modes.
 
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Old 01-22-07, 08:03 PM
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I'd suggest the Honeywell VisionPro TH8110 since you just got a single stage furnace.

http://www.hotfreshcool.com/visionpro_demo.html

Circ is a setting that turns the fan on and off ramdomly. About 35% of the time.

Reason I use Circ at night is that our bedrooms is over a garage, and right now there is no insulation between the space and ductwork, so with the set back at night, the cold garage cools down the ductwork down.

Also I use Circ in the summer cuz the A/C don't run much at night, just enough to move air around as needed.. I leave fan in AUTO in the day time so the humidity is not thrown back into the home.
 
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Old 02-03-07, 06:39 AM
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I have a similar issue with my basement, first floor and second floor not being consistent temps throughout.

I'm just trying to understand what might be best in my situation. I only have a 1 zone system and generally just have my HVAC fan set to auto and try to regulate temps throughout the house by balancing using the adjustable floor registers.

What does running the fan the whole time do that makes the temps more even throughout the home?
 
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Old 02-03-07, 11:19 AM
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I'm sure the experts here will give you a better answer, but in my case I believe leaving the fan on evens out the temperature between floors because the warmer air upstairs is constantly pumped back downstairs rather than all the hot air sitting in the upper floor. Granted, the recirculated air is not as warm as when the furnace is heating it, but it still helps. In addition, in my case, having the fan on pulls the warm air from the registers at the back of my basement through to the front. This in itself helps even out the temperature in the basement alone. It used to be warmer near the vents and colder further away. I still need the oil filled heater in the finished basement when it's really cold, but I do notice quite a difference just with the fan. I'm waiting to catch a good deal on the VisionPro thermostat, and then I'll install one of those too.
 
 

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