"Lucy, you go some 'splaining to do..."

[lspencer534]

I got tired of constantly getting my propane tanks refilled for heat in my work shop, so I did some research on the efficiency/cost of various heat sources (propane, electricity, butane, etc.). One Google article said essentially this: All properly functioning electric heaters are 100% efficient, meaning that for every dollar you spend you get a dollar's worth of heat. Heat pumps are 300% efficient: For every dollar you spend you get $3 worth of heat.

Huh? I thought that no machine is 100% efficient, must less 300% efficient. And what about different costs for the same energy source, such as a kilowatt/hour costing 10 cents in my area but 20 cents in Michigan? I have no idea what the actual cost is, but using those figures, can a Michiganer bring his electric heater to Mississippi and get $2 worth of heat for his dollar? And if I took my heater to Michigan would I get only 50 cents worth of heat for a dollar?

Are they saying that the 3:1 heat/cost ratio for heat pumps is actually you get 33 cents worth of heat for every dollar you spend for electricity for an electric heater and 99 cents worth of heat for every dollar you spend on a heat pump? BTW, electric heat is cheaper for almost all of the Country right now.

[boracayjohnny]

It's on the internet so it must be true.

Talk to an HVAC dude and, maybe, Hank Hill.

[Uncle Meat]

It's on the internet so it must be true.

Talk to an HVAC dude and, maybe, Hank Hill.:rofl:

http://cdn.meme.am/instances/28060048.jpg

[island14]

Pics of Lucy? :island14:

[Mike Mercury]

Heat-pump is most efficient (when it is not requiring back-up). Next is Propane, then nat gas closely behind.

[DAB]

the more insulation you have, the less heat loss you will have, and thus, the less heat input of any kind will be required to maintain a given interior temp.

[ZipZap]

They must be talking about energy efficiency, not overall efficiency. Nothing is 100% efficient overall, but think about something like windpower. Electrical energy wise, it's way more than 100% efficient because electrical energy out >>> electrical energy in. Wind is free, right?

For a standard electrical heater, the current is run through a resistor, so theoretically all of the electricity is turned into heat. 100% efficiency.

For a heat pump, most of the energy (heat) is taken from the surroundings and moved to another location. There is an electrical cost to do this, but your not just changing electricity to heat. I don't know if 300% is right, but given the right conditions, they can be very efficient.

They become inefficient as the temperature differential between the areas exchanging heat becomes large, say 40-50F. Most are limited to an absolute differential, driven by efficiency. That's why you don't see them much where the temps go below 0F.

[mrvette]

Heat pump is fine, until the outside temps drop down to ~45f or so, because the COLD side of your HVAC unit is now outside trying to keep from icing up, while the HEAT is keeping you comfy.....BUT eventually that cold side frosts up due to the outdoor humidity freezing on the coils.....so when the happens the thing goes into AIR CONDITIONING mode, to defrost the outside coils.....

so to put heater coils in the airflow that turn on to keep the air at a reasonable temp in the house.....resistance heaters cost $$$$ to run in the defrost cycle....I can't imagine a heat pump operating up north....all the time in the defrost/resistance heat/cycle.....

Nat gas off the street is the way to go up north......even propane if you have to.....

:seasix::leaving:

[MrPeabody]

When I built my house in '05, propane was cheap, so we have a propane furnace. Right now I use electric space heaters because it's much cheaper than propane. Propane would have to be around a buck a gallon for it to be practical to heat my house. Plus, the furnace heats the entire house, where with space heaters I can selectively heat individual rooms at different temperatures.

[Sneaks]

Heat pump is fine, until the outside temps drop down to ~45f or so, because the COLD side of your HVAC unit is now outside trying to keep from icing up, while the HEAT is keeping you comfy.....BUT eventually that cold side frosts up due to the outdoor humidity freezing on the coils.....so when the happens the thing goes into AIR CONDITIONING mode, to defrost the outside coils.....

so to put heater coils in the airflow that turn on to keep the air at a reasonable temp in the house.....resistance heaters cost $$$$ to run in the defrost cycle....I can't imagine a heat pump operating up north....all the time in the defrost/resistance heat/cycle.....

Nat gas off the street is the way to go up north......even propane if you have to.....

:seasix::leaving:

Todays heat pumps are way better than older models. I've had a heat pump for two years now and haven't experienced any difference in heat, or electric bill varience, when the temp is below freezing. Even when the temps have dropped below zero a couple times, it has been just fine. I know it is much better than the old oil furnace.

[Sneaks]

Pics of Lucy? :island14:

And there it is the obligatory VB response. :cert:
:D

[Olustee bus]

what I don't understand is how much is heat worth. Is it sold by the pound. square feet. who sets the going price.

[8Up]

In order to calculate efficiency you have to have two states of the same item or element. The only real comparison I see in the article you sited is that a heat pump is 3x as efficient as a propane heater. Whatever you pay for something is 100% of what it is worth to you ('actual value' is different). But it has nothing to do with how efficient it is.