Question about Heat Pumps (power, electric, electricity, physics)
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In this day and age, I cannot understand, why, they cannot make a heat pump for different areas of the country. They are putting out so many now up here in PA, and yet, when the temp reaches below 32 degrees they are terrible. They run, and run, and don't heat as well....that to me, is surely not energy efficent?
And yet, they are installing so many of them now....
doesn't make sense to me? Does anyone else ask these questions...
Putting in sheetmetal duct costs less than pipes and radiators.
If you have ducts... then you can do AC as well as heat.
If you really need AC you're done.
Well, unless you're where it actually gets cold.
The ONLY solution is dual fuel (with oil or gas fired burners).
But if you're going to have these... you may as well just do them to begin with.
Gas/oil furnace (or boiler & baseboards).
Add a couple window shakers too for the 5 weeks they're needed.
Just like grandmom did.
In this day and age, I cannot understand, why, they cannot make a heat pump for different areas of the country. They are putting out so many now up here in PA, and yet, when the temp reaches below 32 degrees they are terrible. They run, and run, and don't heat as well....that to me, is surely not energy efficent?
And yet, they are installing so many of them now....
doesn't make sense to me? Does anyone else ask these questions...
And they only last between 10 - 13 years?
Whats up with that?
Can someone explain this to me in layman's terms?
I'm no expert and can't explain it in precise technical terms, but I have had one for the last 9 years or so and know generally how they work.
Essentially, a heat pump running in the winter is an air conditioner running in reverse. In the summertime, heat from inside your home is "pumped", through the process of mechanical compression, pumping, and expansion of the coolant, to the outside air. In the in winter, the process is reversed - so that the outside air becomes the "heat" source. So you can see the problem when it gets very cold. Though there is some heat energy even in air well below, say, 40 degrees, there isn't near enough to allow for an efficient transfer process. So my heat pump has an electrical heater element that kicks in automatically when it takes longer than a pre-programmed time to raise the inside temperature. The heat element is much more expensive to run.
So I don't see how or why they would be installing a lot of them, at least as a sole HVAC source, in any area with real winters. Out here they make sense, since we very rarely go below freezing and even dips into the 30s don't last but a few days. So my electric element doesn't run very often. If that element had to run on a constant basis, it would be much more expensive than gas heat. It is probably a little more expensive anyway, but in the big picture that cost is offset by the lack of a need for gas piping and furnace components.
Last edited by CrownVic95; 02-08-2018 at 12:29 PM..
In this day and age, I cannot understand, why, they cannot make a heat pump for different areas of the country. They are putting out so many now up here in PA, and yet, when the temp reaches below 32 degrees they are terrible. They run, and run, and don't heat as well....that to me, is surely not energy efficent?
And yet, they are installing so many of them now....
doesn't make sense to me? Does anyone else ask these questions...
And they only last between 10 - 13 years?
Whats up with that?
Can someone explain this to me in layman's terms?
The short answer is the Carnot cycle doesn't allow for creating energy out of nothing. The next shortest answer is economics, where initial costs are balanced against running costs, lifespan, and maintenance costs.
Ground source heat pumps do exist, but the initial cost is outrageous. Certain geographic features, such as springs and artesian wells are unique enough that only large users can front the costs.
Heat pumps have "emergency heat" that kicks in an alternate heat source. If that is natural gas, just switch over when the temps go real low.
Unit life varies. There are a lot of factors that enter in to why some last only a few years while others soldier on.
In this day and age, I cannot understand, why, they cannot make a heat pump for different areas of the country. They are putting out so many now up here in PA, and yet, when the temp reaches below 32 degrees they are terrible.
It's the physics of how a heat pump works.You need an alternative heat source
I also live in Pennsylvania, and last year. Do a weather profile for where you live. For 2017 I had:
17 days entire day below 32 degrees| average of average day temperature 20.71 degrees F
21 days average for the day below 32 degrees, but not the the entire 24 hours| average of average day temperature 27.67 degrees F
62 days where the low for the day below 32 degrees, but not the average | average of average day temperature 37.02 degrees F
I know how that there are much colder places in PA.
Then try and make a guess as to how much it costs to heat your home for part of the day when the house is cold.
Unless you have more detailed information you must guess the average number of hours for partial days.
So I am going to be conservative and estimate that one electric space heater is on 1200 W as back up heat, gives me 1387.2 kilowatt hours
At $0.11 per kWh = $152.59 per year.
I do try to use the 600 Watt setting on the space heater. You can make the appropriate adjustments for multiple space heaters or different hours per day or different space heater settings.
Since a space heater costs about $50, and the electricity to run it might be in the range of $150, it would seem in this case that doing something more elaborate is pointless. If your estimate is in the thousands of dollars, then just buy a heat pump with a backup heat source (like propane). But your upfront costs will be very high.
The only other option is to pay through the nose for a geothermal heat pump which could take 20 or 30 years to pay back.
Last edited by PacoMartin; 02-08-2018 at 05:04 PM..
Air sourced heat pumps get their heat from, you guessed it, the air. When you compress something you are also compressing the heat energy and it gets hot. If you have an air compressor for example and compress air into the tank the tank will get warm. If you let it sit there for while the compressed air will equalize in temperature with the ambient temperature. When you release air from the tank and decompress it will now feel cold, same thing applies to aerosol cans.
Since the energy you are utilizing to move this heat is electric we can make a side by side comparison to resistance electric heat. Electric heat is considered 100% efficient because all of the available BTU's are utilized to make heat, if you have natural gas on the other hand some of the available heat in the fuel will be expelled out the chimney and may only be something like 85% efficient.
In the shoulder seasons when the temperature outside is 60 degrees an air sourced heat pump may be 280% efficient over regular electric, in other words you are getting nearly 3 times the heat compared to regular electric. As the temperature drops there is less heat in the outside air so the pump needs to run more and the efficiency drops. At X temperature it will be the same as regular electric heat. Running it below this point will cost you more. X depends on the model, newer ones are operating well below the mid 30's which was typical for older models. When they reach X they will typically switch over to the auxiliary heat, typically standard electric.
You would not have heat pump designed specifically for colder weather because any climate would benefit from one that is more efficient.
While a heat pump is going to use far less energy over regular electric you would also need to include install and maintenance costs if you wanted to do a true cost comparison. When comparing to other fuels it is a whole other ballgame because the cost per BTU becomes a factor. Here in PA the cost per BTU for electric may be 3 times what it is for natural gas or even more than that for coal. The costs for fuel to run the heat pump would only be comparable during mild weather.
I have a calculator here for doing fuel cost comparisons, it's a work in progress and I still need to accommodate air sourced heat pumps which is bit difficult to say the least because it requires some important data input from the user. You can use the ground sourced heat pump section to play around with some numbers for air sourced heat pump.
Try widely overestimate your single space heater usage. Assume that we run the space heater at full power (1200 watts) for 24 hours per day for every one of the 100 days when the temperature drops below 32 degrees for even one hour in the day.
That is 24*100*1.200=2880; 2880*$0.11=$316.80 which is about double my more accurate guess.
It's an overestimate since I am assuming that I am running a space heater at full power for 24 hours on a day when the high is 53 degrees, the average is 42 degrees, and the low is 31 degrees.
To rip out you heat pump and replace it with one that uses propane when it is cold will cost you some multiple of $316.
Sometimes, if it is not very cold the 600 Watt setting will be sufficient.
Of course, if there are multiple people in the house, one space heater will not be enough.
What my concern is, when the temp., drops to 32 degrees or below, they are incredible inefficient, they don't blow nearly as much warm air out into your home, and they run and run and run all night long to keep up....
my question is, if we can create smart cars that drive themselves, why can't they come up with a much more heat efficient furnace/heat pump.
It just seems to me, that we lack intellectual skills, or, they just don't want to make something that works better.
Here is an example.
I had a service man come to the house last night, and I also have a handy man. They both told me, that with our technology out there today, they surely ought to be making household appliances much better than before, that last. But, saving us money isn't their first concern. For instance...laundry machines. I asked him what the best one out there is, b/c I've had several and have not been pleased with mine. Especially the one I have now. These energy efficient washers don't work nearly as well as when you filled the entire tub up with water, and they don't clean as well. And if you don't believe me, do a search for washing machines and read the reviews. He told me, right now, Speed Queen are the best...but the government is looking to put more regulations on them, which also makes it tough.
Vacuums, are a joke....I've had every kind of Vacuum out there, almost, and I swear they are designed by men, who never ask a woman what she needs to help make them better?
So, what I'm saying, is, All over PA, as they are building new homes, and BTW it does get cold here....they are installing heat pumps. Heat Pumps are not efficient, in cold weather below 32 degrees, so if they want to be so confounded concerned about the appliances being energy efficient, why the hell don't they design better equipment and use better parts, making them last?
Good Lord, this is 2018 and by now we should be much further along.
honestly, the only thing they care about anymore is money....they don't care about energy efficiency...
What my concern is, when the temp., drops to 32 degrees or below, they are incredible inefficient, they don't blow nearly as much warm air out into your home, and they run and run and run all night long to keep up....
my question is, if we can create smart cars that drive themselves, why can't they come up with a much more heat efficient furnace/heat pump.
It just seems to me, that we lack intellectual skills, or, they just don't want to make something that works better.
Here is an example.
I had a service man come to the house last night, and I also have a handy man. They both told me, that with our technology out there today, they surely ought to be making household appliances much better than before, that last. But, saving us money isn't their first concern. For instance...laundry machines. I asked him what the best one out there is, b/c I've had several and have not been pleased with mine. Especially the one I have now. These energy efficient washers don't work nearly as well as when you filled the entire tub up with water, and they don't clean as well. And if you don't believe me, do a search for washing machines and read the reviews. He told me, right now, Speed Queen are the best...but the government is looking to put more regulations on them, which also makes it tough.
Vacuums, are a joke....I've had every kind of Vacuum out there, almost, and I swear they are designed by men, who never ask a woman what she needs to help make them better?
So, what I'm saying, is, All over PA, as they are building new homes, and BTW it does get cold here....they are installing heat pumps. Heat Pumps are not efficient, in cold weather below 32 degrees, so if they want to be so confounded concerned about the appliances being energy efficient, why the hell don't they design better equipment and use better parts, making them last?
Good Lord, this is 2018 and by now we should be much further along.
honestly, the only thing they care about anymore is money....they don't care about energy efficiency...
No, we didn't all miss your question.
Heat pump efficiency is limited by physics, not lack of intellectual skills. As to why they are installing them all over PA, I can only conjecture that it's due to relatively low new construction cost....future electric bills be damned. Perhaps more regulation is needed, as the builders' agenda has little in common with the consumers'. Buyer beware.
Like I said, out here they make a lot more sense. In your neck of the woods, for efficiency you need a serious furnace.
Heat pump efficiency is limited by physics, not lack of intellectual skills. As to why they are installing them all over PA, I can only conjecture that it's due to relatively low new construction cost....future electric bills be damned. Perhaps more regulation is needed, as the builders' agenda has little in common with the consumers'. Buyer beware.
Like I said, out here they make a lot more sense. In your neck of the woods, for efficiency you need a serious furnace.
yes, indeed, it's crazy...and they want to talk energy efficent? I'd rather had an oil bill, or electric bill, with something that was more efficient.
I mean, it's crazy, the things run and run and run very hard when the temps go down under 32 degrees and when your talking 15 - 0 degrees, it runs, but doesn't heat well at all....can't keep up.
So why the heck are they installing them? I see them all over the place, matter of fact, my girlfriend who lived in NJ had a huge Georgian home that used a heat pump?
Then why install them at all....and yes, your right, if you live in a more mild climate, yes, indeed, they would be energy efficient, my son has one, well, most homes where he lives has them...but to place them in PA and North, is crazy?
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