Electrical question, Buick/Deere others.

If I have a space heater that is 120vac and draws 10 amps then that is 1200 watts.......yes?


If I have a space heater that is 240vac and draws 10 amps then is the cost 1/2 of the 120vac to run it?
Amps * Volts = watts (and you pay per kilowatt)

120 * 10 = 1200 watts

240 * 10 = 2400 watts.
I am confused?
Where is the money savings?
Please explain. For us non-electrical engineers.

A good question actually.
You are correct, the 10amp 240V heater uses 2400watts per hour while making 8184 btu.
No money savings as a watt is a watt but......Given the same sized supply wire the and same wattage. There is less loss/heating/wasted power in the supply cbales.
Engineers do consider power cable losses as a serious heat calculation. Regarding power conductors heating making extra air conditioning load in large buildings.
My well meaning maternal GrandFather always claimed he was using only half the power to run the electric water heater. By conencting it 120V rathe rthan 240V.
He couldn't understand that total KW hrs were exactly the same .And that it would take four times longer for the tank of water to reach full temp.

You turn the 240V heater off sooner... or you get more heat. Your call. It consuming twice as much power but may be putting out more than twice as much heat depending on efficiency...

Rod

Actually a good question gun man.

The utility charges for the energy you consume which is volts x amps x time i.e. Watt Hours

If you use a 240 volt heater and it draws 10 amps for 1 hour, you have used 240 x 10 x 1 = 2400 watt hours / 1000 = 2.4 KWH

If you use a 120 volt heater and it draws 10 amps for one hour, you have used 120 x 10 x 1 = 1200 watt houres/1000 = 1.2 KWH.

If you use a 240 volt heater and it draws only 5 amps for one hour, you have used 240 x 5 x 1 = 1200 watt hours/1000 = 1.2 KWH.

Even though copper wire is a relatively low resistance conductor, there are still I squared R resistive heat losses across the length of the wire runs which is sort of wasted as heat energy versus other energy a tool might deliver. However if you use a higher supply voltage and a tool draws less current, theres less wasted heat energy lost in the cord.

Something to consider though, if theres heat losses in the wire to the electric heater, thAT heat is given up to the air and does what the heater is doing anyway, so thats not such a loss now is it !!!!!!!!!!!!!

John T Retired Electrical Engineer but try to explain in laymans terms best I can

So it is the same money per hour for each voltage but..........I get twice the heat out of it or use it half the time.

The reason I am asking this is cause I would like to get one of those 4000 watt electric heaters (a backup) to the pellet burner and my main furnace is a piece of schitt, it works but I have had $2200 in service calls in 10 years and yesterday I had to have a new blower motor installed. (disgusting what the high eff. furnaces cost in parts and maint.)
The high eff. furnaces cost Triple of a regular furnace and parts are double and more parts to break.....ZERO FOOKING SAVINGS THERE. I told the service guy that I hated this furnace and I just might say.....F**** it and rip it out when something else breaks.

I'm not certain what the question is?
4800W on 120 or 240V for 15 minutes, 2400W on 120 or 240V for 30 minutes or 1200W on 120 or 240V for one hour. They all cost exactly the same. And produce the identical amount of heat.

You are paying for power used or KWH.
I understand......I think.
The electric meter doesnt care if you used a 120v single breaker or a 240v dual breaker, KWH used is KWH used.

You have it 100%

Gun Guru, as others have said....a watt is a watt...you cant beat that. If you hook a 1200 watt load to 120 it will draw 10 amps. If you hook it to 240, it will draw 5 amps. You dont buy your electric by the Amp, you buy it by the watt.....


There are a lot of people who think this way....

If you have Nat gas, get a new furnace. one with a real service contract or guarantee. There are great high tech furnaces.
Ground heat source heat pump systems are even better. Jim

If calculating total heating costs, the energy, machinery,parts and service. Some of these ultra high efficiency furnaces or ground source heat pumps. Make for very expensive heating and cooling.
Stopping the air leaks in and out of a house. Is cheaper than the price of a new higher efficiency heating or cooling system.

....unless you're on a demand meter. Given it's your home I'd be 99.99999% certain you're not on demand... but if you were then there would be load/demand charges based on current draw.

Rod

Going demand here this month on the 8th. Dirty rotten s.o.b's in Queens park are going to add 50% to my power bill. To pay off their buddies in the green energy cram.

"Where is the money savings?"

It's in the initial cost of the electrical cable needed to run the 240 volt appliance, as compared to the cost of the cable needed to run the same wattage appliance operating on 120 volts.

Paul

Demand on your home? Ouch.
Don't tell NSP or that will be the next fix for their money grabs. It seems like a constant news story here where they're going to their 'fuel escalator' clause to get rate increases from the UARB. About every 3 months it's back in the news...
People might not mind paying it so bad if they'd cut the trees of the bloody lines.

Rod