What is a dual stage furnace ? How do I figire the cost of gas/btu vs. kilowatt/btu ?

[thefatguy]

Dear friends, before I call the furnace guy I want to understand:

1) what is a dual fuel furnnace - who makes such a beast ?

2) I live in seattle - how does one compare kilowatt/btu VS. therm/btu ? Is the efficiency trade in a place like seattle worth considering other options - like heat pumps; and dual fuel furnaces ?

Thanks

[BaldLoonie]

A 2 stage furnace has 2 levels of heat. Low which is 60-70% of full capacity for mild weather and high for the coldest weather. Everyone makes them.

Post your cost of juice per kilowatt hour and cost per therm of gas.

[dhvac]

I think you maybe talking more 2 separate fuels verses a 2 stage that bald covered
In which case it would more then likely be a heat pump down to a certain temp (determined by the heat loss of your house) then at that temp you would switch over to a fossil fuel
You do this when it is cheaper to run a fossil fuel then it would be to run a heat pump with electric back up
Or you want to feel the hot air of a fossil fuel coming out of the registers when it is cold out


As for the best well that goes back to the question that is asked the most often here and the answer is always IT DEPENDS ON WHO INSTALLS IT

[lksmith]

Hi Bald,

Can I hijack this thread long enough to throw in my costs of NG and electricity?? I'm paying $1.39/therm of NG and my electricity cost is 8.77¢/kw. What would my economic balance point be for my heatpump dual fuel setup. FWIW my furnaces are 80% AFUE 2 stage V/S.

Thanks in advance.

Larry Smith