new ac/heat pump

grannyj7August 7, 2012

i am wanting to get a new ac/heat pump. I need a 2 ton and am looking to have more energy efficiency. I now have a 2 ton trane with 10 seers and my energy bills are very high. I am considering a Carrier....any suggestions?

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tigerdunes

G

What is your location?

IMO

    Bookmark   August 8, 2012 at 8:57AM
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tigerdunes

G

Here is my personal checklist.

Obviously correct sizing is important. If you are unsure, then request a load calculation or even perform it yourself for a nominal fee online.

there are three equally important components-quality HVAC, the install by dealer, and probably the most overlooked and disregarded is the ductwork system.

these are my minimum specs for a new HP system. both outside and inside units should be replaced to have a properly matched system.

15 SEER, 12.5+ EER, 9 HSPF
best matching VS air handler
full BTUs in both cooling and heating for your rated size
R-410a refrigerant(same as Puron)
scroll compressor preferred
electronic demand defrost preferred
thermostat with "dehumidify on demand" feature
staged backup heat strips
new and correctly sized refrigerant line set

you want a thorough inspection of your ductwork system. size, overall condition, supply and return lines, insulation qualities, leak test, etc.

any hot/cold spot issues in your home should be addressed.

I would only use authorized dealers for the various brands that provide quotes.
see mfg websites.

I would look at Trane/AmStd,Rheem/Rudd,Carrier/Bryant.

Depending on your location, I would not purchase a new HP system that did not have electronic demand defrost.

IMO

    Bookmark   August 8, 2012 at 9:26AM
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cindywhitall

granny,
If you spend some time on this board you will learn so much! I know the experts will want a lot more info from you such as where you live and the size, age, style etc of your house and whether your old system did a good job or not. Do you use a furnace and, if so, have you considered that you may need to replace that as well?

tigerdunes,

how does location influence the need for demand defrost? In the Carrier line would that be known as "ideal defrost". I'm in NJ. Do I need demand defrost here with a gas backup? What climate would need it the most and can you explain why?

I think my contractor might be recommending a hp unit that is a little lower than I should get (to keep costs down) , the 25HCC. He says the Infinity Control is needed for it to operate as a hybrid (and calculate the crossovers etc). It will have an Infinity furance which I think is needed for the blower if I understand it correctly. When I asked about that hp with Infinity he said they will work together. He said this about the Infinity control when I questioned using it.

"a standard heat pump thermostat will work, but will always use the heat pump for 1st stage and only use the gas furnace for 2nd stage if the heat pump can't satisfy the thermostats call for heat. This is not a hybrid system and it is outdated 25 year old technology. With the Infinity control it calculates the most cost efficient way to heat your home based on thermostat deviation from set point and outdoor temperature. It then cycles the equipment the most intelligent and comfortable way. The standard heat pump thermostat is only used on straight heat pump with air handler applications that have electric backup heat instead of a gas furnace as its backup."

I want it all (as do we all). The best quality, comfort and efficiency at the lowest price....I know I have to compromise somewhere to get the price...

    Bookmark   August 8, 2012 at 4:05PM
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cindywhitall

granny,
If you spend some time on this board you will learn so much! I know the experts will want a lot more info from you such as where you live and the size, age, style etc of your house and whether your old system did a good job or not. Do you use a furnace and, if so, have you considered that you may need to replace that as well?

tigerdunes,

how does location influence the need for demand defrost? In the Carrier line would that be known as "ideal defrost". I'm in NJ. Do I need demand defrost here with a gas backup? What climate would need it the most and can you explain why?

I think my contractor might be recommending a hp unit that is a little lower than I should get (to keep costs down) , the 25HCC. He says the Infinity Control is needed for it to operate as a hybrid (and calculate the crossovers etc). It will have an Infinity furance which I think is needed for the blower if I understand it correctly. When I asked about that hp with Infinity he said they will work together. He said this about the Infinity control when I questioned using it.

"a standard heat pump thermostat will work, but will always use the heat pump for 1st stage and only use the gas furnace for 2nd stage if the heat pump can't satisfy the thermostats call for heat. This is not a hybrid system and it is outdated 25 year old technology. With the Infinity control it calculates the most cost efficient way to heat your home based on thermostat deviation from set point and outdoor temperature. It then cycles the equipment the most intelligent and comfortable way. The standard heat pump thermostat is only used on straight heat pump with air handler applications that have electric backup heat instead of a gas furnace as its backup."

I want it all (as do we all). The best quality, comfort and efficiency at the lowest price....I know I have to compromise somewhere to get the price...

    Bookmark   August 8, 2012 at 4:06PM
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weedmeister

Location effects whether you go into defrost modes very often or not. A milder climate (say Georgia) will not so much. A colder climate (say PA) will.

The Carrier unit has timed defrost and will activate on a 'use time' basis whether defrost is needed or not.

    Bookmark   August 8, 2012 at 5:18PM
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cindywhitall

Is the "used time " a bad thing? If the backup is a furnace is the on demand as important? I'm sure the contractor will try to tell me it's fine when really the on demand is better, so I'd like to know more for when it comes up. Thanks weed.

    Bookmark   August 8, 2012 at 6:15PM
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tigerdunes

Weed is correct.

Demand defrost on a HP is a big deal in a colder climate over a more moderate climate.

Demand defrost eliminates/reduces unnecessary, nuisance, and expensive defrost calls over timed temp cheap defrost method.

And again it is bad forum etiquette to hyjack threads. This particular forum member is very conflicted in his/her HVAC project and perhaps would be better off renting.

TD

    Bookmark   August 9, 2012 at 6:53AM
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cindywhitall

Last post in this thread....

To follow up, I don't understand why defrost on demand is important for a hybrid system with gas backup. I think my furnace will kick on at 40 degrees or so. As long as the heat pump is not running below freezing wont it just not freeze up and not need defrost at all? I assume it has some kind of sensor not to just go into defrost every "x" minutes when it is above a certain temp. I would certainly want it if I was going to use it in freezing conditions, but I don't want to insist on it if defrost would not be needed much, if ever.

Thanks

    Bookmark   August 9, 2012 at 10:45AM
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tigerdunes

Important depending on balance point and changeover point between gas and electric. For Jersey, I certainly would want DD.

However, unless you are familiar with HP, I don't think you will like it from a comfort standpoint. Then there is the cost difference between the HP versus straight AC version. Plus you need a cost analysis to even see if there is an operating advantage of HP versus nat gas.

Lots to consider especially when you are as conflicted over your project as you seem to be.

IMO

    Bookmark   August 9, 2012 at 10:54AM
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mike_home

I don't want to participate in post hijacking, but I seem to have this urge to respond to Cindy's posts. ;)

If you have hybrid system with a 95%+ efficiency furnace then you will see very little run time with your heat pump given the current price of natural gas. This assumes the contractor has calculated and set the lock out temperature of the heat pump and furnace correctly. The amount of energy the demand defrost may save is not going to be very much.

    Bookmark   August 9, 2012 at 11:02AM
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tigerdunes

Surely demand defrost would eliminate 100s of defrost calls over time/temp in a NJ location whether straight HP system with air handler or a DF system.

IMO

    Bookmark   August 9, 2012 at 11:06AM
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weedmeister

C: The timed defrost does not care what the outdoor temp is. It just activates off of the accumulated time.

G: if you have a 10 SEER unit now, a 15 SEER unit should save you around 20% (don't quote me) on your electrical used by the HP. However, heating is measured differently with HPs so it would be good to know your location.

    Bookmark   August 9, 2012 at 6:29PM
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neohioheatpump

Demand defrost is definitely important.
Don't get me wrong though, if you have a gas backup and only run the heatpump down to 40 you won't be going into defrost as much because of the simple fact your not running the heatpump as much.

Without demand-defrost though even above 40 you will still get more unnecessary defrost calls. Demand-defrost is worth it. Not only saves energy but creates less annoying defrost calls. Its annoying when your heat-pump goes into defrost because it makes noise going into and out of defrost.

Rheem/Ruud, and York/Coleman/Luxaire, Trane/Am. STd have demand deforst.

    Bookmark   August 10, 2012 at 9:29AM
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tigerdunes

Neohio is correct.

However why have a DF system with the HP only running down to 40 degrees?

Assuming the reason you have a DF system is to leverage one fuel against another, a 40 degree changeover to the backup fuel would defeat the purpose of DF and cost you more in operating costs.

IMO

    Bookmark   August 10, 2012 at 9:34AM
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cindywhitall

Tiger,
Thought I was done here, , sorry....I have no real idea what the crossover temp would be here in NJ. 40 was just my guess. I also did more reading and now see that the unit itself reaches 20'degrees colder than the air, so it could freeze. Is that correct?

Looks like carriers Ideal Defrost or Amanas smart shift are the best 2 chOices available from those brands, so I will make sure my quotes include a model with those features. I also read something about a TXV...would that help,if the unit didn't have the special defrost features?

    Bookmark   August 10, 2012 at 10:33AM
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tigerdunes

Make no mistake. You can call it any name you want.

But Carriet nor Amana do not have true electronic demand defrost.

And for your location, I wouldn't have either in HPs in a DF system.

IMO

    Bookmark   August 10, 2012 at 10:47AM
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energy_rater_la

well..there went your thread granny.

cindy, please quit hijacking other people's
threads.

    Bookmark   August 10, 2012 at 11:26AM
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mike_home

I forgot demand defrost is a timed set up. I have no experience with heat pumps since they are so rare in NJ.

The Evolution/Infinity system makes the heat pump operation even more complex because there is a range of temperatures where either the heat pump or furnace may operate.

Cindy wants the heat pump because it "saves" her money under the NJ Clean Energy program. My recommendation would be is to use the heat pump only as an air conditioner. This will add a few years of usable service to the unit.

    Bookmark   August 10, 2012 at 11:31AM
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cindywhitall

granny never came back and posted since the first post....

Mike understands where I am with this. I would have the option of what temperature to use the hp at. My understanding is that there will be a range of temps where I can go hp or furnace. The idea is to "save" $ because I can get hp cheaper (in a sense). If I get hp I will essentially get a new hot water heater and air sealing/insulation "free" and with financing.

This hp sounds like it may not be the great value i thought it was, and may create more headaches....The other option to "save" more is to get normal a/c and get a tankless water heater......

I have to figure out if there is a serious downside or risk to hp here in NJ or not....(considering the cost to me will be the close to the same as a/c)

    Bookmark   August 10, 2012 at 12:41PM
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countryboymo

When it is just normal winter weather I rarely notice defrost cycles on my system compared to my old timed defrost system. I would say 1/4th. One those days where its 30 degrees and spitting snow/sleet it will run more than my timed system did because it needs to. If its 20 degrees and snowing which around here usually its much more dry snow and doesn't seem to stick in the unit unless the flakes are huge it doesn't defrost as much but it is still more than dry weather.

So with timed defrost it just defrosts cause the time is up.

with demand defrost unless the sky is falling the cycles are tremendously reduced which saves money but also helps with wear and tear on the unit cycling back and forth.

The biggest jump in savings between a/c/heatpump is going from a builders grade piston orifice timed defrost.. to a txv controlled demand defrost unit.

Adding these two options along with a x13 or variable speed blower and x13 motor on the outside unit and a noise blanket on the compressor for noise and you have something that will spec into the mid 14 seer with over 8hspf possibly pushing close to 9hspf.

    Bookmark   August 12, 2012 at 3:44AM
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tidemeover

I'm looking to move from oil steam heat and AC to a Lennox XP16 heat pump for $9000. I've been warned that the heat pump will struggle to heat the first floor (of two) -- because the compressor is in the attic. I'll still have the oil for really cold weather, but I'm hoping the heat pump will be sufficient for much of the year.

???

Thanks,
tidemover in PA

    Bookmark   July 12, 2013 at 12:40PM
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tigerdunes

This is an old thread. Considered bad form to piggyback onto another's thread.

Start your own. Go to bottom of main page. I am sure you will get some helpful replies.

IMO

    Bookmark   July 12, 2013 at 12:51PM
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