# How many kilowatts heating element ?

#### Externet

Joined Nov 29, 2005
1,533
A natural gas house heating furnace is 90000 btu/hr; runs less than 20% (perhaps 10%) of the time on a normal winter to keep the house comfortable.

What electric heating element power could the gas burner be replaced with ? No problem if turns on 80% of time to supply the same amount of heat.

#### kubeek

Joined Sep 20, 2005
5,732
If i remember correctly, 1 BTU is equal to energy needed to rise the temperature of 1 pound of water by 1°F. Sadly I couldn´t be bothered to translate such a silly unit into anything meaningful

Joined Jul 18, 2013
21,377
1 kW = 3412.142 BTU/hr
Electric furnaces come in 10kw to 27kw on average. In about 7 models.
I have one for my garage that has 5 element selections for heat.
Max.

#### #12

Joined Nov 30, 2010
18,210
90,000 BTUs/Hr is 26370 watts.

Do you feel like you got pounced on?

(I assume you can do the math now that you have the conversion factor.)

Best regards
HP

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#### #12

Joined Nov 30, 2010
18,210
Perhaps ~5KW 'burning' 80% of the time...
The humans will feel more comfortable if the heater runs softly most of the time, and you aren't wasting the power used for the fan motor. It converts to heat at the same efficiency.

I have the same feeling about flammable fuels. Then again, people who don't understand electricity can be just as suspicious of electric heat. The difference is, a fault in a properly installed flammable gas system can sneak up on you in several ways. A fault in a properly installed electric system just makes it stop.

ps, a kilowatt of heater means a kilowatt hour per hour.

If you have any doubts, you can buy the 10KW heater and don't connect half of it. If all else fails, connect the other half.

Joined Jul 18, 2013
21,377
All the same, I agree with the OP -- Natural/LP gas service is an explosion and/or fire waiting waiting to happen! HP
To put it in perspective, I happen to live in a city of over 600,000 and the home heating, including water heating, is predominantly natural gas, it is extremely rare to ever hear of explosion/fire due to gas related, if it happens, it is often due to someone doing something stupid such as laying a basement floor using highly flammable adhesives etc.
I consulted with my son-in-law who is a Fireman of 20+ yrs and he bears out the statistics that gas is not a principle cause of fires by any stretch.
But due to the cost of Hydro electricity becoming more cost effective, there is now a trend to electric heating, after all we do have 15 hydro electric generating stations here. It should almost be free!.
Max.

#### wayneh

Joined Sep 9, 2010
16,399

#### MrAl

Joined Jun 17, 2014
7,792
Correct. 20KW is closer to the 90000 BTU equivalent of 26KW. But the time the gas actually burns in the furnace is ~10% in one hour.

Perhaps ~5KW 'burning' 80% of the time...

Hi,

For this and your previous post before that one...

The difference in units is due to it being either a rate or just a set quantity. But time is always present so sometimes we dont have to mention time. A 10kw load that runs continuously is operating in time even though we dont mention that in the "10kw" itself.

Time does get involved when the device does not run continuously however because then we have to consider the total energy, or the energy averaged over some time period.
If we have a 40kw heater that runs 25 percent of the time then the total energy output is the same as a 10kw heater that runs for 100 percent of the time (continuously non stop). The only thing you have to watch out for is the original rating may be taking into account the worst case heating requirements. If the 40kw heater normally runs at 25 percent duty cycle, it may be that the original designer chose that rating because it was known that in that particular geographical location the temperature could occasionally drop much lower than the norm, and that 40kw would be required for rare but still possible weather conditions. Substituting a 10kw device may work most of the time, but may fail short during those extreme weather condition times. So some care has to go into choosing what size to install, and maybe a second one for those possible extreme times.

Another consideration is the local/global distribution of the energy. We dont want all the heat in one location in the house, we want it distributed evenly so that all areas can get the heat they need. This may mean also taking into account the insulation properties of each room especially in older homes that have insulation in some walls and none or less in others. Cost considerations may make it worthwhile to add insulation in some areas.

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#### Hypatia's Protege

Joined Mar 1, 2015
3,226
We also allow the power company to turn off our A/C compressor if they want, when the rate exceeds \$0.14.
But isn't that when you'd need it most (assuming cost follows demand)? --- FWIW I could improve the rate for my residence building was I to permit the 'POCO' to 'fiddle' with power to my hot water boilers -- 'Tho there's something a bit too 'Orwellian' in that for my taste... --- My major 'gripe' is with their assessment of reactive power 'consumption' (do note the quotes) Re: my 3-θ (so-called 'industrial' service) though as long as usage remains in excess of the 5000 kWh/Mo 'wholesale threshold' it 'balances out' -- even so - until recently it was illegal to bill for 'VARs'... They know what their doing too - They seem to know it's not quite worth my while setting up an 'intelligent' power factor compensator -- Sly little gits!!!

Well hey! -- Kudos on your arrangement! -- Seems you're getting a better deal than could be hoped for with a private wind farm?

Best regards
HP

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