We just move into our house in may so we've only used the AC. We have 2 electric ac units and 1 electric furnace (for 2nd floor) 1gas furnace (for 1st floor and basement). My question is will my electric bill be really high this winter running the electric heat and the gas heat? The highest its been this summer running both electric AC's all the time was $160 but I dont know if the furnace takes more energy. Can someone give me an idea what the average cost is for an electric furnace heating 900sqft?

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Electric (resistance) heat is the least efficient way, both money wise and environmentally. I assume they are heat pumps by your description, if they are, then you should be OK. A heat pump doesn't use any more electricity than an AC unit until the outside temps get really cold, causing extra heat strips to come on. A heatpump is essentially an AC unit "running backwards".

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'87 GT, daily driver
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Our house has what is called a "dual fuel" system.
It runs the A/C during the summer. During the winter it runs the heat pump until it gets too cold (in the 20s) for the heat pump to keep up. Then it lights a conventional set of gas burners to assist. (They'll also come on if the thermostat commands a large temperature increase, like if the house is really cool and the heat has been turned off.)
I suspect that yours is the same. The gas system is just used for the lower floors. The upper floor won't need it since the heat will rise, anyway.

This is the most economical heating system I have ever seen. I really like ours.
Is the 900 sqft. the total? Or is it 900 sqft for each floor?
Either way, I'll be surprised if you exceed $200 most months.

OK let me explain the set up a little more. We have a furnace the runs on gas in the basement heating 2600 sqft of the basement and 1st floor. Then we have a electric furnace in the attic running 900 sqft of the second floor. Then we have 2 seperate AC units outside 1 running the basement and 1st floor and 1 running the 2nd floor. Does this make since now? I'm just worried that on the cold winter days that the 2nd floor furnace is goign to get expensive. I already kinda know what the gas furnace will cost in the basement cause we had gas in our old house.

[This message has been edited by FieroAngel (edited 09-22-2006).]

i agree, i dont think the electric one will have to come on much since the heat will go upstairs.

how much of the upstairs living space?
do you have to keep it heated?

Yeah, you should be ok. If you're trying to save money, though, cut the upstairs furnace down low, and bump up the downstairs unit a little. Since heat rises, the upstairs unit probably won't have to come on much except when it's really cold.

Run heat only on the low levels and see how that works before turning on the electric upstairs. Remember that heat rises.

If it is a little cold upstairs not a big deal. You mostly sleep up there. Use an electic blanket or get a water bed. If you need heat in a bathroom for showering, install a small heater in that room. It doesn't make sense to heat a whole floor when you aren't using it.

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[This message has been edited by theogre (edited 09-22-2006).]

another thing to think about is you gas furnace (flame) dry's out the air alot compared to electric
so thats a good contribution to why people have dry skin in the winter

quote Originally posted by $Rich$: another thing to think about is you gas furnace (flame) dry's out the air alot compared to electric so thats a good contribution to why people have dry skin in the winter

The type of furnace shouldn't matter. The flame on a gas furnace doesn't come in contact with air circulated through the house. I heats up air passing through a heat exchanger. The air from the flame is exhausted out the flue pipe to get rid of combustion gases.

Regarding the relationship between humidity and temperature, heating has no effect whatsoever with the amount of water in the air. However, since the amount of moisture that a given amount of air can hold (saturation, 100$ humidity) is directly proportional to temperature, the relative humidity will decrease as the air temperature rises. So, in the winter when you heat it feels drier because the warmer air has less moisture relative to it's total capacity. Also, when the outside temperature falls below freezing the outside humidity drops to essentially zero, that adds to the dryness of inside air.

In summer when running air conditioning it's completely different since one of the main goals is to dehumidify the air. Drier air feels cooler because you can sweat more easily and therefor dump more heat.

JazzMan