Furnace fan power consumption?

DIYGST · 04-17-2010, 05:52 AM

Does anyone know how much electricity is consumpted approx. by the blower fan? Does it run off the 220V circuit or is it the 110V furnace breaker circuit?
Does not count freon compressor.

Just Bill · 04-17-2010, 07:12 AM

Most forced hot air furnaces run on 115, heat pumps and A/C compressors run on 240, but the fan that delivers the air run on 115. Motors vary depending on the age of the unit, older units are not as energy efficient. Many modern muti-speed heaters run on DC voltage. There should be a plate on the heater somewhere that tells the power draw in amps. Power consumption in watts(P)= voltage(E) x current(I). That is a rough answer because AC voltage works differently than DC. But roughly, a motor that draws 5Amps consumes 575Watts.

DIYGST · 04-18-2010, 02:43 AM

So how much power does a typical compressor itself draws? it's on a 30amp 220V breaker.

frenchelectrican · 04-18-2010, 05:06 AM

For the air handling unit { indoor unit } if straght A/C unit typically the motour useally wired for 240 volts and the motor size will varies a bit depending on how big the unit itself some are at 1/3 and some are on 1/2 and few case at 3/4 HP setting.

But if you have furance with A/C coil on it then the motor useally be on 120 volts due there are other couple motours in there. for motour size it the same as I mention above.

Now for outdoor freon compressour unit that will varies a bit by tonnage size and how effect the unit it is.

The key item is look at the nameplate on the unit it will have all the info there and some of them will list the running amps on there.

Merci,Marc

DIYGST · 04-19-2010, 01:35 PM

I look at the compressor and see some FLA numbers (1, 1.3 etc) but it says minimum amp 17amps that's 240V*17amps minimum when it runs?
I am trying to compare the consumption of a whole house fan vs an A/C system.
But the furnace blower itself is almost as much power as the whole house fan itself. However I don't think an A/C runs constantly in an hour. maybe switch on 5-6 times depends how fast the room is heating up again.

Yoyizit · 04-19-2010, 02:00 PM

http://www.google.com/search?client=...UTF-8&oe=UTF-8

04-17-2010, 05:52 AM	#1
DIYGST Member Join Date: Nov 2008 Location: CA Posts: 307	Furnace fan power consumption? Does anyone know how much electricity is consumpted approx. by the blower fan? Does it run off the 220V circuit or is it the 110V furnace breaker circuit? Does not count freon compressor.

04-17-2010, 07:12 AM	#2
Just Bill Member Join Date: Dec 2008 Location: Wilmington, DE Posts: 3,098	Furnace fan power consumption? Most forced hot air furnaces run on 115, heat pumps and A/C compressors run on 240, but the fan that delivers the air run on 115. Motors vary depending on the age of the unit, older units are not as energy efficient. Many modern muti-speed heaters run on DC voltage. There should be a plate on the heater somewhere that tells the power draw in amps. Power consumption in watts(P)= voltage(E) x current(I). That is a rough answer because AC voltage works differently than DC. But roughly, a motor that draws 5Amps consumes 575Watts.

04-18-2010, 02:43 AM	#3
DIYGST Member Join Date: Nov 2008 Location: CA Posts: 307	Furnace fan power consumption? So how much power does a typical compressor itself draws? it's on a 30amp 220V breaker.

04-18-2010, 05:06 AM	#4
frenchelectrican " Euro " electrician Join Date: Apr 2006 Location: WI & France { in France for now } Posts: 5,100	Furnace fan power consumption? For the air handling unit { indoor unit } if straght A/C unit typically the motour useally wired for 240 volts and the motor size will varies a bit depending on how big the unit itself some are at 1/3 and some are on 1/2 and few case at 3/4 HP setting. But if you have furance with A/C coil on it then the motor useally be on 120 volts due there are other couple motours in there. for motour size it the same as I mention above. Now for outdoor freon compressour unit that will varies a bit by tonnage size and how effect the unit it is. The key item is look at the nameplate on the unit it will have all the info there and some of them will list the running amps on there. Merci,Marc

04-19-2010, 01:35 PM	#5
DIYGST Member Join Date: Nov 2008 Location: CA Posts: 307	Furnace fan power consumption? I look at the compressor and see some FLA numbers (1, 1.3 etc) but it says minimum amp 17amps that's 240V*17amps minimum when it runs? I am trying to compare the consumption of a whole house fan vs an A/C system. But the furnace blower itself is almost as much power as the whole house fan itself. However I don't think an A/C runs constantly in an hour. maybe switch on 5-6 times depends how fast the room is heating up again.

Furnace fan power consumption?