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View Full Version : People will say heat pumps don't work


redhot916spd
2011-01-29, 01:51 PM
but simply put what has been happening for a long time are installs that are done wrong.
A heat pump when installed correctly can yield 100,000 btu's for 55 cents

an 80% efficient furnace will give you the same btu's for 99 cents and a 95% efficient will do it for 83 cents.

Propane will cost $2.29 for an 80% and 1.88 for a 95% efficient

The issue with heat pumps can come down to this simple error your installer did. The lineset from the Heat Pump to the indoor coil needs to be filled with Nitrogen when the lines are installed. Watch this and demand it of your HVAC tech's . Those fuckers are the reason I went to school and am now trying to pass this along and save you the money and the headache. That oxidation can gum the check valves if not caught by a dual flow filter.

3uP-eb8Zz08

http://image.made-in-china.com/2f0j00plaQjiTSFEUP/SFK-Reversible-Heat-Pump-Filter-Driers-Bi-Flow-.jpg

I have been fucked over buy these guys 3 times in the past, never again!! The old adage is if you want something done right you have to do it yourself.

sleek98
2011-01-29, 02:12 PM
I have a heat pump. Heating my 1600 sq foot house was 150 for the last month. 150 for my total electic bill so my bare min bill with no heat or ac is normally around 70 so 80 bucks to heat is cheap I think.

redhot916spd
2011-01-29, 02:16 PM
I have a heat pump. Heating my 1600 sq foot house was 150 for the last month. 150 for my total electic bill so my bare min bill with no heat or ac is normally around 70 so 80 bucks to heat is cheap I think.

do you know what kind of r rating you have in your walls and cielings? I would like to take a stab at the load calculations? How many windows and doors do yo have and are they the normal 2'x3' windows?

sleek98
2011-01-29, 03:49 PM
No Idea on the R rating. we have about 14 inches of pink insulation in the attic, 10 windows, 1 big sliding glass door and a front door, 2 car garage thats under the master. We share a wall though as it is a townhome, so im guessing that helps. Last billing period was 32 days and we used 1954 KWHs or 61.06 a day. Our 40 gallon hot water heater is also electic.

redhot916spd
2011-01-29, 04:20 PM
No Idea on the R rating. we have about 14 inches of pink insulation in the attic, 10 windows, 1 big sliding glass door and a front door, 2 car garage thats under the master. We share a wall though as it is a townhome, so im guessing that helps. Last billing period was 32 days and we used 1954 KWHs or 61.06 a day. Our 40 gallon hot water heater is also electic.

it will take me a couple days but I will run some numbers on this , thanks

Corners
2011-01-29, 05:05 PM
A heat pump when installed correctly can yield 100,000 btu's for 55 cents

an 80% efficient furnace will give you the same btu's for 99 cents and a 95% efficient will do it for 83 cents.



So, what is the cost of electricity, gas, and COP of the heat pump you're using in that calculation? I hate it when companies throw out numbers like that without the information behind them. A lot of times, they'll tweak the numbers to make their products look better than others, leave out taxes and fees, etc.

I can tell you, what we're paying here with all the taxes, fees, and other BS, this is what energy costs today in JoCo (numbers from my December bills AFTER all taxes and fees, so REAL numbers)....

Gas = $7.00 per MMBTU (1)
Electricity = $0.099 per kwh, or $29.0 per MMBTU (2)

So, for 1 MMBTU of heat, the following costs are....

80% eff furnace = $8.75
95% eff furnace = $7.37
Resistance heater (like normal electric water heater, or heat pump supplemental heater) = $29.00
Heat pump with COP of 3 = $9.66 (assuming no supplemental resistance heat, also keep in mind that COP drops with ambient temperature, so the heat pump brochure mights say 4, that's most likely based on a higher ambient temp. When it's 30F or so, it's not 4).

1)Atmos Energy, using 1 MCF = 1 MMBTU
2) KCPL, using 3,413 BTU/kWh

Corners
2011-01-29, 05:30 PM
And BTW, I'm not anti heat pump at all. They do a great job at moving heat from outside (yes, there is still heat in the 30F air) to inside. The issue around here is, natural gas is cheap. If you're talking about the north east where you're heating with fuel oil, or live out in the sticks and run propane, an electric heat pump will kick their ass and pay for itself in a decent amount of time. But here with natural gas all piped up to your house for $7 per MMBTU delivered, a heat pump really isn't going to save you much, if any. Payback is generally longer than the life of the heat pump.

redhot916spd
2011-01-29, 06:42 PM
So, what is the cost of electricity, gas, and COP of the heat pump you're using in that calculation? I hate it when companies throw out numbers like that without the information behind them. A lot of times, they'll tweak the numbers to make their products look better than others, leave out taxes and fees, etc.

I can tell you, what we're paying here with all the taxes, fees, and other BS, this is what energy costs today in JoCo (numbers from my December bills AFTER all taxes and fees, so REAL numbers)....

Gas = $7.00 per MMBTU (1)
Electricity = $0.099 per kwh, or $29.0 per MMBTU (2)

So, for 1 MMBTU of heat, the following costs are....

80% eff furnace = $8.75
95% eff furnace = $7.37
Resistance heater (like normal electric water heater, or heat pump supplemental heater) = $29.00
Heat pump with COP of 3 = $9.66 (assuming no supplemental resistance heat, also keep in mind that COP drops with ambient temperature, so the heat pump brochure mights say 4, that's most likely based on a higher ambient temp. When it's 30F or so, it's not 4).

1)Atmos Energy, using 1 MCF = 1 MMBTU
2) KCPL, using 3,413 BTU/kWh

winter seasonal rate 0.0381/kw couple that with the efficiency of the heat pump operating at a 2x ratio of a considered 100% efficiency electric furnace.(100,000/3413btu)= 29.299 KW divided by the efficiency ratio (how many times more efficient) twice than an electric furnace=14.6495x.0381/kw =.558/100,000 btu's (oops sorry I was off a 8/10s of a penny) I got these numbers in class the other day


page 3
http://www.kcpl.com/brochures/CIPricing_MPS.pdf

Winter Season is the eight consecutive months beginning October 1 through May 31.

Corners
2011-01-29, 07:14 PM
winter seasonal rate 0.0381/kw couple that with the efficiency of the heat pump operating at a 2x ratio of a considered 100% efficiency electric furnace.(100,000/3413btu)= 29.299 KW divided by the efficiency ratio (how many times more efficient) twice than an electric furnace=14.6495x.0381/kw =.558/100,000 btu's (oops sorry I was off a 8/10s of a penny) I got these numbers in class the other day


page 3
http://www.kcpl.com/brochures/CIPricing_MPS.pdf

Winter Season is the eight consecutive months beginning October 1 through May 31.
Look at your bill, man. That's not what it comes into your house after taxes and fees. For that matter, the raw price of gas is $4.xx per MMBTU, but comes out on the bill at $7.00 after all the other BS.

Also, here is KCPL's Kansas tariff ($0.069 per kWh for and all electric house before taxes and fees for the winter)

http://www.kcpl.com/about/KSRates/Sched11.pdf

Edit. Just looked at your link. That's for industrial service. They're billed differently than residential customers. They have usage costs, like your home, but on top of that they have a demand charge as well, and usually a power factor penalty.

redhot916spd
2011-01-29, 08:18 PM
Look at your bill, man. That's not what it comes into your house after taxes and fees. For that matter, the raw price of gas is $4.xx per MMBTU, but comes out on the bill at $7.00 after all the other BS.

Also, here is KCPL's Kansas tariff ($0.069 per kWh for and all electric house before taxes and fees for the winter)

http://www.kcpl.com/about/KSRates/Sched11.pdf

Edit. Just looked at your link. That's for industrial service. They're billed differently than residential customers. They have usage costs, like your home, but on top of that they have a demand charge as well, and usually a power factor penalty.



Your link doesn't have the heat pump rate which is different and you are right I did quote the commercial , my bad

First 600 kWh/mo. $0.0944/kWh $0.0663/kWh
Next 400 kWh/mo. $0.0566/kWh $0.0663/kWh
Over 1,000 kWh/mo. $0.0473/kWh $0.0464/kWh

http://www.kcpl.com/brochures/HeatRateMO.pdf

I get into that cheaper rate because my house is running 175,000 btu's hr on avg.

brb

Corners
2011-01-29, 08:59 PM
Your link doesn't have the heat pump rate which is different and you are right I did quote the commercial , my bad

First 600 kWh/mo. $0.0944/kWh $0.0663/kWh
Next 400 kWh/mo. $0.0566/kWh $0.0663/kWh
Over 1,000 kWh/mo. $0.0473/kWh $0.0464/kWh

http://www.kcpl.com/brochures/HeatRateMO.pdf

I get into that cheaper rate because my house is running 175,000 btu's hr on avg.

brb

Those are the non-heat pump rates for MO. Look one column over. ;)

Anyways, compare that to gas now. It doesn't work out that great because our gas is so cheap around here.

redhot916spd
2011-01-29, 09:55 PM
looks like they are giving you a price break if you use a heat pump, I have heatpump/ nat gas zoned units myself I like them they are cheap to run

I must do that math

redhot916spd
2011-01-29, 09:58 PM
Those are the non-heat pump rates for MO. Look one column over. ;)

Anyways, compare that to gas now. It doesn't work out that great because our gas is so cheap around here.one thing about your gas heat is that you still have not figured in your electric rate to circulate that heat. I will agree the heat is the largest part of the energy consumption !!

Corners
2011-01-29, 10:56 PM
one thing about your gas heat is that you still have not figured in your electric rate to circulate that heat. I will agree the heat is the largest part of the energy consumption !!

It's pretty small. But again, you're not factoring in the supplemental resistance heaters needed when it actually gets "cold" outside. ;) Oh well.

Heat pumps, yes, they use less energy than gas sources, but because gas is so cheap in this area (for now), a heat pump really doesn't pay for itself.

redhot916spd
2011-01-30, 01:26 PM
It's pretty small. But again, you're not factoring in the supplemental resistance heaters needed when it actually gets "cold" outside. ;) Oh well.

Heat pumps, yes, they use less energy than gas sources, but because gas is so cheap in this area (for now), a heat pump really doesn't pay for itself.

heat pumps cost about 10% more than a new a/c unit does which works out to about 200 bucks for a new unit and I have gas furnace as my back up which is plenty warm.

But what I would like to add is my neighbor added a new one last fall and I was outside firing up my snow blower and I noticed that the damn thing was running when the temp was 15 degrees outside. The new ones are growing ever more efficient. My old ones kicked off and the furnaces took over at 29 degrees.

snm95ls
2011-01-30, 01:31 PM
Only 10% more than a new AC unit? You are obviously not talking about ground source units then.

redhot916spd
2011-01-30, 01:36 PM
Only 10% more than a new AC unit? You are obviously not talking about ground source units then.

no I was talking strictly heat pump units
looks like an A/C unit except it has a 3 way valve.

Corners
2011-01-30, 10:01 PM
Hey, question for you. Since you're in HVAC school and have access to better resources pertaining to real world applications (I'm an ME, but I don't install this shit for a living), what do you say about the claim that heat pumps have half the life of the typical AC unit. You know, since they run twice as long per season?

And if you ever want to bounce heat load, or any other heat transfer or thermodynamic valve off me, please do. I love that shit. It's what I do for a living. PM any time.

snm95ls
2011-01-30, 10:09 PM
Heat transfer?

FFFFUUUUUUUUUUUUUU!!!!!

Corners
2011-01-30, 10:46 PM
Heat transfer?

FFFFUUUUUUUUUUUUUU!!!!!

Basics, man. The basics. Dont bring me your differential equations. ;)

snm95ls
2011-01-30, 10:47 PM
Basics, man. The basics. Dont bring me your differential equations. ;)
Well that is no damn help.

:ryan:

Corners
2011-01-30, 11:05 PM
:dupe:Well that is no damn help.

:ryan:

:). I left all that shit in Lawrence. I have programs and other resources to figure all that stuff out for me now.

redhot916spd
2011-01-31, 08:10 AM
Hey, question for you. Since you're in HVAC school and have access to better resources pertaining to real world applications (I'm an ME, but I don't install this shit for a living), what do you say about the claim that heat pumps have half the life of the typical AC unit. You know, since they run twice as long per season?

And if you ever want to bounce heat load, or any other heat transfer or thermodynamic valve off me, please do. I love that shit. It's what I do for a living. PM any time.

your question is exactly what my instructor has said general contractors tell him, the truth though is how critical the install is. They are not pulling vaccuum down to 3-500 microns and they are not testing for leaks overnight with a Nitrogen pressure test. When some tech does an install in one day for an a/c unit. You are going to have issues. The heat pumps should last every every bit as long as an A/C. I have been screwed over and over and that is why I went to school. There are so many dumbasses out there installing shit wrong and screwing people over by doing shitty work. Lemme ask you this have you ever heard about doing a Nitrogen test or has any tech ever said he this process takes time to do it right? Most contracters are ill informed. I had a guy at the firehouse and he had been doing installs since the 50's. He is now about 76 years old. He was never formally educated in the process. It sucks but it is what it is. I have no desire other than to help people and pass along the knowledge so we all get treated better.

And yes thank you I would love to bounce some math over to you to check some numbers. I have a summmarization page for the numbers that correlate to the KC area but would love another ME looking over my shoulder at this.

Corners
2011-01-31, 10:34 AM
The heat pumps should last every every bit as long as an A/C.


On a yearly basis, or on an hourly basis? For example, around these parts, take fictitious 5 year old units. The heat pump should have over twice the hours on it as compared to the A/C. If life expectancy is determined by hours running, then an A/C would have over twice the life as a heat pump.

Looking it up on the internet, I'm not seeing a clear answer, but I am seeing some claims by people (no hard data, though) that a heat pump does have less of a life than a typical A/C and furnace. Ask your teachers if they have any data on life expectancy. I'm sure a big variable would be on where you live. If you live in AZ and your heating season is minimal, I'm sure the A/C and heat pump would have about the same life. But up in the northern parts of the country, the cooling season is short, thus the hours on each unit would lead me to believe the A/C would last quite a bit longer. Around here, we have a much greater heating degree days than cooling degree days. In other words, our heating equipment gets run longer and harder than our cooling equipment. Here's our heating and cooling degree days...

Kansas City, Mo.
Heating degree days 5,326
Cooling degree days 1,388

This would lead me to believe than a heat pump is going to have more hours on it heating than compared to cooling, thus on a yearly basis, a typical heat pump would have roughly 4.8 times the hours on the compressor and unit as compared to a traditional A/C. I don't see how a heat pump could last nearly as long as an equally built and installed A/C.

redhot916spd
2011-01-31, 12:26 PM
On a yearly basis, or on an hourly basis? For example, around these parts, take fictitious 5 year old units. The heat pump should have over twice the hours on it as compared to the A/C. If life expectancy is determined by hours running, then an A/C would have over twice the life as a heat pump.

Looking it up on the internet, I'm not seeing a clear answer, but I am seeing some claims by people (no hard data, though) that a heat pump does have less of a life than a typical A/C and furnace. Ask your teachers if they have any data on life expectancy. I'm sure a big variable would be on where you live. If you live in AZ and your heating season is minimal, I'm sure the A/C and heat pump would have about the same life. But up in the northern parts of the country, the cooling season is short, thus the hours on each unit would lead me to believe the A/C would last quite a bit longer. Around here, we have a much greater heating degree days than cooling degree days. In other words, our heating equipment gets run longer and harder than our cooling equipment. Here's our heating and cooling degree days...

Kansas City, Mo.
Heating degree days 5,326
Cooling degree days 1,388

This would lead me to believe than a heat pump is going to have more hours on it heating than compared to cooling, thus on a yearly basis, a typical heat pump would have roughly 4.8 times the hours on the compressor and unit as compared to a traditional A/C. I don't see how a heat pump could last nearly as long as an equally built and installed A/C.

You do have a valid point about longevity, the factory rates them both at 20 years of service , the issue boils down to install. Jesse Harding(program instructor) told me today the normal life he sees is about 8 years. Dick Decker(retired KCPL guru and Heat pump and geothermal instructor) said his was working fine when he took his 20 year old unit out and upgraded. One of the issues that I learned about the industry is that they removed start capacitors of the units. Everyone presumed that they are engineered to work fine without them. But what we see today is a more frequent swapping of units due to failure. Heat is an issue with a permanent split capacitor motor. I recommend hard start kits. It takes half the amps to turn the electric motor. If you could cut your energy consumption in half say to go from 0-60mph in your car , would you do it? I would.

Anywho it seems to me this shit has been engineered to fail to make them more money. Scroll compressors do seem to have an advantage over piston type compressors. But if a tech doesn't use nitrogen to braze the lines at the outdoor and indoor coil and pull a great vacuum of 3-500 microns, the benefits of the new eqiupment could be lost in as little as a couple years.

The industry has alot of growing up to do.

redhot916spd
2011-02-02, 10:40 PM
Just came across some of the math for heat pumps example a 3 ton or 36,000 btu heat pump works out like this


Heat pump(btuh)
_____________________ = Coeffiecient of Performance

heat pump kWh usage x 3413

36,000 Btuh
__________________
4.219kWh x 3413 Btuh/kwh

36,000
____________
14,399


COP = 2.5 meaning a heat pump is 2.5 times the more economical to operate than an electric furnace

Go4Broke
2011-02-06, 12:26 PM
So I work at an apartments complex that uses heat pump uints with electric heat back ups and this is the first time I have had to deal with them. At what point do most heat pumps start to become inefficient? I hear the alot of northern states don't use heat pumps because of how cold it gets.
I think Heat pumps are great for most apartment commuinties since installing so many gas lines is costly and I just think is dangerous. The uints we have where installed in 1995 so I don't they they have a function to turn themselfs off and run off electric heat only, it has to me manualy switch to emergency heat.

redhot916spd
2011-02-06, 03:14 PM
So I work at an apartments complex that uses heat pump uints with electric heat back ups and this is the first time I have had to deal with them. At what point do most heat pumps start to become inefficient? I hear the alot of northern states don't use heat pumps because of how cold it gets.
I think Heat pumps are great for most apartment commuinties since installing so many gas lines is costly and I just think is dangerous. The uints we have where installed in 1995 so I don't they they have a function to turn themselfs off and run off electric heat only, it has to me manualy switch to emergency heat.


well you would have to read the schematic to see, the ones I have on my house are carriers without the dual fuel kit(installed incorrectly) and mine switch to e heat at 29 degrees. The new ones have a seer rating about twice what was installed in 95

inis
2011-02-10, 05:38 PM
Redhot, when do you finish schooling?

I was looking to upgrade my furnace and a/c to something newer. I'm currently on propane and need to get as far away from it as I can. I can install everything myself, but it certainly wouldn't hurt to have someone whos been through schooling for this around.

redhot916spd
2011-02-10, 05:57 PM
Redhot, when do you finish schooling?

I was looking to upgrade my furnace and a/c to something newer. I'm currently on propane and need to get as far away from it as I can. I can install everything myself, but it certainly wouldn't hurt to have someone whos been through schooling for this around.

end of march but what do you need, if you need someone to sweat the lines correctly with nitrogen and pull a vacuum down to 500 microns or less , I would be glad to help, that shouldn't take to long. To do it right we should let the nitrogen sit overnight to pressure test it

Oh BTw I just got a new price list in and the the dealership reduced the prices of the high efiiciency's by about 28%,good time to buy.

inis
2011-02-10, 07:06 PM
end of march but what do you need, if you need someone to sweat the lines correctly with nitrogen and pull a vacuum down to 500 microns or less , I would be glad to help, that shouldn't take to long. To do it right we should let the nitrogen sit overnight to pressure test it

Oh BTw I just got a new price list in and the the dealership reduced the prices of the high efiiciency's by about 28%,good time to buy.

Sweat the lines, check everything over. I've got a business acount at charles d jones and also johnstone. I currently have a goodman, and have not had any major issues...so I might stick with them.

redhot916spd
2011-02-10, 08:14 PM
Sweat the lines, check everything over. I've got a business acount at charles d jones and also johnstone. I currently have a goodman, and have not had any major issues...so I might stick with them.

is it r-410 or is it r-22 do you have the matching evaporator? is it a txv or is it a fixed metering device?

inis
2011-02-11, 01:26 PM
New set up will be 410, if the r22 is the banned stuff..I already have some. I have a couple tanks in the basement I bought when it all was being banned. I've not purchased any of the new set-up. I might consult you when I get to that point.

redhot916spd
2011-02-11, 02:01 PM
couple things to think about, your lineset needs to be thoroughly washed out , the chemical sprays are about a hundred dollars or the new lineset will set you back for 150 for a 25 foot line set, whatever evaporator you have be sure it was engineered for the refridgerant you have. You do want to make sure the A/C setup you have is sized correctly for your home. If you get to large a system for your house it will short cycle and not get rid of the humidity correctly (cools down too fast before the evaporator has time to get rid of all the latent heat in the house) if you get too small a system , well obviously its btu output will not be enough to cool the house when its ultra hot out. Thats why its good to do a load calculation on the house if you are hodge podging equipment together. For the record we can still get r-22 if that is what you need. They are just not making the equipment for it anymore. I think it is all supposed to phases completely out by 2030.?

T-Wayne
2011-02-11, 02:52 PM
My house is just under 5,000 square feet. I have a heat pump and my electric bill is $300 in the dead of winter.

redhot916spd
2011-02-11, 05:14 PM
My house is just under 5,000 square feet. I have a heat pump and my electric bill is $300 in the dead of winter.

2x4 walls or 2x6? How thick is the insulation in the attic? Might be dead on for that large amount of space. A heat pump loses efficiency as the temps go down. Mateing a heat pump with a high HSPF with a high efficiency nat gas furnace is the best way to go if you can't do a geothermal heat pump. The 2 efficiency maps compliment each other well. Now if you are saying you have a heat pump and you have your electric bill averaged and it is 300/month it might be a tad high? Without doing a load calc for this region I really couldn't tell you. You have to take into account the kind of window's , double pane, shaded, doors. garage doors, r-rating in the walls , the amount of insulation in the furnace.