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Hey guys,

I am shopping for air conditioners for through-the-wall units. Some of them have heat. My home currently uses baseboard heat which is really expensive.

Does anyone know what the relative efficiency of baseboard heat vs the heating in one of these A/C units? If its not any better I'd rather not spend the extra money, but it would be nice to have a cheaper heat medium if it is better.

Here is the unit I'm considering:

http://www.lg.com/us/air-conditioners/lg-LT1236HNR

-Jeff
 

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First, improved efficiency would come from improving your home insulation and air sealing. Then, if you want a combination of ac and heat, look into a heat pump, which uses electricity, but delivers either heating or cooling at a much lower cost. If you have multiple rooms, then look at a mini-split system.

Bud
 

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I hate to sound confusing but it depends on the cost of fuel. Generally electric is higher, I have no idea of your cost but I would think that the heat strips would be a higher cost
Yes, you are confusing us. All electric resistive heaters have the same efficiency --- 100%. That is to say that 100% of the electricity that you put into it turns into heat. A fan will just distribute the heat throughout the room better. A mini-split (heat pump) has higher efficiency because it is not a resistive heater, it pumps the heat from outside into your home.
 

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No, that is just an air conditioner. The heat function is just resistive heat strips.

Bud
 

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Jeff,
My apology if I missed it, but approximately where are you, climate zone.
Also, do you own, rent, and is this a condo, row house, or single residence?

With electric heat you have an opportunity to reduce both heating costs and air conditioning cost with a heat pump. They use an outside unit to extract or discharge heat to provide either heating or cooling. Think half price on your electric bill, depending somewhat upon what other electric uses you have.

Bud
 

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The efficiency of electric resistive heat is 100 percent whether they are heat strips on a window air container or a baseboard. A given number of BTUs will cost you the same. I would look at heat pump/ac unit . That will be cheaper to run
 

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Then that thing isn't going to change your heating bill. It makes heat exactly same way as your baseboards.
1 Watt = 3.4 BTU/hr --- so if you do the math to the spec sheet, that unit is just converting the electricity into heat.
 

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The LG unit you link to, as others have said, just has resistive heating. Your electric bill will be identical to baseboard heaters (but the LG will be louder and expensiver).

Resistive heaters are 100% efficient - which will still bankrupt you.

Much better, as others have said, are heat pumps, which have efficiencies close to 400%.... ie. unit suckles 1000 watts from your electrical outlet, but injects 4000 watts of heat into your house.

"But wait!", you say, "a 1000watt outlay returns 4000? Where'd the extra 3000 come from?"

The answer: a heat pump does not use the electricity to create heat; it simply moves heat (that's the "pump" part) from one place to another.

The drawbacks are:
#1) huge upfront cost
#2) if the outdoor temperature drops below... -10°C(? anyone?), the pumping ceases.... and then the heat pump unit switches to.... wait for it... resistance heating mode. Ground- or water-source heat pumps don't have this problem (but they have double or triple of problem #1).

I once new a guy who just used a regular window AC backwards in the winter. In the fall, he'd pull the AC out of the window, spin it 180, and shove it right the hell back in. Not sure how well this worked....
 

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#2) if the outdoor temperature drops below... -10°C(? anyone?), the pumping ceases.... and then the heat pump unit switches to.... wait for it... resistance heating mode. Ground- or water-source heat pumps don't have this problem (but they have double or triple of problem #1).
A reasonable HP can work down to -25C (-12 or -13 F) and still beat out resistive heat.
 

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I once new a guy who just used a regular window AC backwards in the winter. In the fall, he'd pull the AC out of the window, spin it 180, and shove it right the hell back in. Not sure how well this worked....

Probably not real well. Since there was no defrost control.
 

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#2) if the outdoor temperature drops below... -10°C(? anyone?), the pumping ceases.... and then the heat pump unit switches to.... wait for it... resistance heating mode. Ground- or water-source heat pumps don't have this problem (but they have double or triple of problem #1).
It's a myth that there's a fixed point where the resistance heat takes over entirely.

Capacity drops as it gets colder, the backup comes on and supplements the heatpump when capacity is lower than heat loss.

That point could be anywhere from 45f to 0f. depends on the heatpump, how it's sized, how well it maintains capacity as it gets colder.

The point to shut the unit down and switch to resistance entirely is when the defrost cycles offset any savings and the minimal amount of heat provided isn't worth wearing the machine out for.
 

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The point to shut the unit down and switch to resistance entirely is when the defrost cycles offset any savings and the minimal amount of heat provided isn't worth wearing the machine out for.
Actually at about -20 and down the air is pretty dry and about the only thing you're running defrost for is the oil return.

Last Winter I was running defrost cycles about every 8 hours (run time), and that was strictly for oil return purposes.... very little frost build up.

At some point however, you are correct, the btu output is low enough (even with minimal defrost time) so it's just not cost effective to run anymore when you take into consideration the wear/tear.
 
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