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yoda888

gas furnace usage equals rediculous electric bill?

yoda888
10 years ago

Hi All,
It's summer here in the US, so I'm not using the heater currently. I figured now is a good time to take a look at it.

During the winter, when we use the gas heater, the electric bill skyrockets. I understand the gas usage increasing since we go from just stove/oven/water gas heating to furnace heating.

However, I did not expect the electricity to increase by so much. My electricity is as high as my gas usage!

Is this normal? Is there something wrong with my heater/blower?

Any help, tips, pointers is greatly appreciated.

Thanks!

Comments (22)

  • tigerdunes
    10 years ago

    Nice little anecdotal story. It would be helpful to provide some facts.

    Can you give typical usage for electric in non heating mths and electric in heating months.

    Are rates the same?

    Keep in mind I am interested in KWHs usage.

    What type gas appliance do you use to heat? Be specific. Is it a forced air furnace? When was it last serviced?

    Post back.

    IMO

  • yoda888
    Original Author
    10 years ago

    Tigerdunes,
    I'll look up the info and post back! Thanks for asking the questions!

    I want to figure this out since the heating bill is outrageous. (Mind you I don't have the heat turned up to 74degrees or anything either! Inside thermostat was set to low 60s)

    EDIT: I was able to look up the usage online. I'll grab the heater brand, model, etc when I get home.

    Here's my usage:
    Date kWh AveTemp(F) Therms
    Jun '12 333 60 14
    Aug '12 351 61 16
    Sept '12 331 61 15
    Oct '12 390 59 19
    Nov '12 604 55 42
    Dec '12 709 48 94
    Jan '13 571 48 96
    Feb '13 498 50 60
    Mar '13 394 54 24

    Thanks

    This post was edited by yoda888 on Mon, Jul 15, 13 at 19:03

  • tigerdunes
    10 years ago

    I agree. Your electric in the heating season has bumped up what appears to be higher than one would expect.

    You have excluded all possibilities other than your gas appliance?

    BTW, what is your location?

    How do you heat your hot water?

    IMO

  • ionized_gw
    10 years ago

    Do residents leave lights on a lot in darker winter months? Do you have a big holiday light display?

  • mike_home
    10 years ago

    Is someone using a portable electric heater?

    Do you have a variable speed furnace? Do you have the thermostat set to the fan on position?

  • yoda888
    Original Author
    10 years ago

    @tigerdunes, The only other gas appliances we have are the water heater, and the gas oven/range.

    We are located in San Mateo, CA (94402).

    @ionized, We do not have any big holiday light display (actually none the past couple of years at all). The lights are on an automatic sensor for 4-hours. Dusk plus 4-hours.

    @mike_home, I will use a portable electric heater at times simply because the power usage goes bonkers whenever I use the gas furnace. But this usage to limited to our master bedroom.

    I don't know if I have a variable speed furnace, how can I check? The thermostat is set to the heat position only. (As another x-factor, I swapped out my previous thermostat for a Nest towards the end of last winter.)

    My utility company (PG&E) gives you "real time" energy usage tracking on line (real time = delay of a couple of hours to 24-hours). I can track when the usage of electricity goes up because when we get home from work, the graph will spike up. In the evening, when we go to bed, I can see that the electric heater (radiator type of heater) does not consume a lot of electricity because the usage graph is not indicating this.

    The furnace we have is a Trane XE80.

    We have never had the furnace serviced. (What does this involve?)

    Thanks!

  • tigerdunes
    10 years ago

    Electric portable heaters are notorious for driving up electric usage and costs.

    As far as your furnace and a service call, tech could check heat exchanger , controls, and make certain furnace blower motor was not consuming excessive electricity and was in compliance specs.

    Sure your neighbor has not run a long extension cord to your home? Just kidding.

    IMO

  • yoda888
    Original Author
    10 years ago

    I know it's not the portable heater as I can track the electricity usage based on time of day. I'm able to correlate it to when I have the furnace on and when I switch over to the electric heater. (Plus I ended up switching to the electric heater because the furnace was so darn expensive to run.)

    So I'm wondering if the blower is consuming an ungodly amount of electricity. There's nothing else really that's part of the heater that should use a lot of electricity I would think.

    I wish it was my neighbor, then at least I could figure out the source of the power consumption. =:

  • Elmer J Fudd
    10 years ago

    I'm in the Bay Area and my usage pattern is similar to yours. My electricity usage goes up 100-150 kwh per month during the heating months.

    We have a setback thermostat and the smart meter data clearly shows the electricity consumption pattern when our furnace is in use, The first hour's warmup is a peak, and then it plateaus out at a lower level while on intermittently, and drops when the furnace is off.

    Electric resistance heaters are hogs. It's easy to estimate usage. If you have a 1000 watt heater, that's 1 kwh per hour of use. 2 hours of on time per day = 60 kwh per month.

  • ionized_gw
    10 years ago

    Can you turn off all the breakers except for the blower, make sure the cooling does not engage (if you have that) and watch your main meter to measure power consumption by the blower motor?

  • yoda888
    Original Author
    10 years ago

    So you're saying turn off the power to everything, and turn on my furnace? (I'm not sure how to engage the blower without turning on the heating element.) I can view the meter, but I'm not sure what units it counts in. I assume we're trying to see how much current the blower is drawing is that correct?

  • tele28
    10 years ago

    I was going to suggest that if it was a one time occurence it may be that the meter reader made an error, but it seems you may have some sort of smart metering. One thing I would suggest especially if you live in a multi-unit dwelling, verify that you are being billed from the correct meter. This actually happened to me when I lived in my condo. I had been paying the neighbors gas bill for almost two years before it was discovered by myself.

  • mike_home
    10 years ago

    "I'm not sure how to engage the blower without turning on the heating element."

    What heating element do you have? I thought the house has a natural gas furnace?

  • jackfre
    10 years ago

    I think a thorough service of the furnace is in order. Dirty air filters can create this type problem as the unit has to run longer to satisfy the stat. Also, probably a small, but contributing issue is that as days get shorter our light usage increases. You could put an amp meter on the blower motor and see if it is within specs. That should be a part of the service call.

  • ionized_gw
    10 years ago

    So you're saying turn off the power to everything, and turn on my furnace?

    Yes

    (I'm not sure how to engage the blower without turning on the heating element.)

    Look a the thermostat. Is there a "fan on" or a "fan only" lever or button? Turn the temp way down to keep the furnace from turning on.

    I can view the meter, but I'm not sure what units it counts in.

    Look at the web, particularly at your power company's web site.

    I assume we're trying to see how much current the blower is drawing is that correct?

    Yes. A clamp-on ammeter would be easier and better if you want to get one.

  • mrjasondude
    10 years ago

    You can also use a Kill A Watt Electricity Usage Monitor around 20 bucks. Clamp-on meter more accurate but the Kill A Watt is very simple to use in comparison. Plug furnace power cable into Kill A Watt , plug Kill A Watt into wall outlet. It can show you amps, volts watts , kwh's used etc.

    P.S, I forgot to mention my oil filled radiator or space heater uses 2x+ the electricity of my 100k btu furnace 1,500 watts in comparison to my furnace blower motor at 700 watts.

    Good luck.

    This post was edited by mrjasondude on Wed, Jul 17, 13 at 13:47

  • yoda888
    Original Author
    10 years ago

    @tele28, yes, my neighborhood is all smart meters, so usage is sent to the utility over the air (and thus I can get my own usage online usually within 1-2hours).

    @mike_home, yes, I have a natural gas furnace. When I say "heating element" i'm talking about the burners that ignite when the heater turns on (most likely i'm using the wrong terminology here)

    @Jackfre, What does a service consists of? I have a feeling they just vacuum it for dust and check the belts. I can do that myself. If they however measure the output, adj the heat produced, etc, then I'm game for it. I have changed the filter and it made no difference in power consumption (and the old one wasn't too dirty to the naked eye.) Can you explain more about contecting the amp meter to the blower motor?

    I can't use a "kill a watt" type of device as my furnace is hardwired to the circuit.

    Thanks all!

  • mike_home
    10 years ago

    In one of your posts you mentioned that you recently installed a Nest thermostat. You want to verify that the thermostat is running your blower 24/7. This would use a lot of electricity.

    The blower motor itself could be going bad, but I doubt it can be using that much more in electricity. If you had a ammeter with a clamp, you could measure the current flowing into the blower. A 0.5 HP motor should use about 373 watts. It may be a little more since there is some load on it. This is something a HVAC tech could do as part of the preventive maintenance and inspection.

    Does your furnace have an electronic ignitor? Maybe the ignitor is never shutting off? It is not a huge power drain, but enough to accumulate over the course of a month. I have never heard of this happening, but it is something that should be checked.

  • Elmer J Fudd
    10 years ago

    "@snidely, during the heating months, how many hours is the heater on? I can say that my average usage per day is probably 1.5-2hours. Which leads me to think the usage is excessive."

    Yes, maybe 1 - 3 hours of actual running per day depending on the weather. Less on weekdays, more on weekends and when entertaining.

    Most Bay Area houses, other than new and carefully constructed ones. aren't particularly airtight nor well insulated. Older ones can be very wasteful to heat. The good news is that it doesn't get too cold.

    I've been here a long while and have concluded than other than being sure a good job is done when repair or replacement of equipment is needed, it's a waste of good thinking time to worry about trying to get significantly more efficient. The payback period for any major retrofits is very long.

    If you have double paned windows and check for big air leaks (like in ductwork), there's little else to do that'll show you any payback besides turning down the temp setting on your thermostat. THAT can make a noticeable difference.

  • yoda888
    Original Author
    10 years ago

    @mike_home, yes, I have a Nest installed now. I can verify it is not enabling the blower at all as the energy reports have been zero. (also, the power usage spikes up during the winter when I'm using the heater only -- right now the power usage is fine)

    I will need to measure the draw on the motor. Or perhaps the previous owner had the blower replaced and they have some gazillion watt motor in there drawing crazy power!

    I'm going to take a look it this weekend. With my wife at home so that if I electrocute myself, my wife can call 911! :p (actually I'll have some time this weekend to look at it)

    @snidely, we had a complete remodel a couple of years ago. New windows, walls opened for insulation and the attic as well.

    The one thing I will be doing is installing a top damper flu on my two chimneys. I suspect warm is leaking out of there. But that doesn't explain why the electricity usage is so high.

    Thanks!

  • yoda888
    Original Author
    10 years ago

    Okay an update!

    Got a HVAC guy out to take a look.

    Long story short is that the furnace itself is drawing 4.6-5amps. According to the guy he said normal is around 2amps or so.

    The inducer itself was drawing over 1amp when he said normally it should be around .25amps.

    The blower was drawing close to 4amps. He said it should be much lower.

    Overall he said a properly functioning furnace should be drawing 1-2amps.

    So I assume that's what's causing my excessive electricity usage.

    I can fix the blower/inducer which would cost about $1500. Or replace the furnace with a 85% efficient furnace for $3700. Or a 97% at $4900! (I think the %s are right, not sure off the top of my head.)

    Does this sound reasonable?

    Thanks!