help please choosing heat pump

[susanc]

We have a 2300 SF 2-story home in SE South Carolina (about 900 SF downstairs, rest upstairs, all bedrooms), about 20 min. from ocean, 10 min. drive from sound. We have high summer temps, very high humidity, for several months, it regularly hits 80 dew point. Right now, day 5 (maybe more) over 100 with insane humidity. That being said, our builder grade 3.5 ton (one zone) Carrier that is 12 yrs. old has been good to us. Until this summer, I could lower the a/c quite low and it kept up fine. Our bills weren't that bad until last summer. Its probably a mix of aging system and rate increases. Last winter, strange noises started when running heat (reverse valve?) but it worked fine, although it was loud. We don't have many nights that are below 30, but it does happen a few times a year. The system does not keep up for them, can't get house over about 65, heat pump runs and runs, and emergency heat does not kick on unless done manually. This summer, the system just quits if it runs too long, I have had to put temp. to normal (as opposed to polar blast) around 73-75 during day, lowering to 71 at night (I used to put it at 69 at night, 71-72 during day). The thermostat isn't quite right, a degree or two off, so 69 setting would mean 70 downstairs, maybe a degree or two more upstairs actual temp. It is colder downstairs, has to be to have comfortable sleeping temp. upstairs. But the cost of zoning is too high. The unit is still working, but I think we are on borrowed time. I'll add the master is above the garage, and runs a bit warmer in summer, and a bit cooler in winter. Its large, and the only vaulted ceiling we have. We can add insulation and another vent possibly, it has two, plus a 14" square return.

I am not opposed to just getting a little better than what we have (lower end single speed 3.5 ton) if it performs a bit better with heat on our few cold nights, a bit more energy efficiency, I was quoted on a Trane XR14. Quite a few bad reviews have scared me, also the two sales people (one Carrier, one Trane) sing the praises of 2-stage systems, even more for variable speed systems… but especially on high end, omg, the price is jaw dropping. I don't know what savings they speak of, it will take years to realize that after paying for the unit. Is 2-stage the big jump to higher efficiency? Is there a large difference of comfort/energy savings for variable? I'm trying to find that sweet spot of energy savings without paying for too much system (for us). It seems above 16 SEER there is smaller energy savings, about 15% more to higher SEERs, is that worth several thousand more dollars for a system? I also wonder how single zone, 2-stories works with 2-stage/VS, I don't want the system running and keeping downstairs all nice and perfect, and not have enough juice for upstairs, which has more cooling requirement.

OK now to what has been suggested so far… Trane XV18 vs. Carrier Infinity 18VS, both came in about same (very high for us) price. Stepping down to 2-stage, Trane XR17 vs. Carrier Performance 16. I wonder since Performance 16 is less money if the Trane XR17 would compare more to Carrier Infinity 16, but I wasn't given a quote for that. Also, I was quoted for a Trane XR15, but I don't understand why a single speed compressor would be paired with a variable speed air handler, but that is minimum for energy star for that model also it is supposed to be more efficient. Is the XR17 that much better with 2-stage compressor?

I would like to possibly take advantage of tax credits and energy rebates, but of course don't want to pay thousands more for a unit for hundreds of credits and rebates, unless of course, we realize enough energy savings to justify it.

Any preferences/opinions/questions are welcomed and appreciated.

[Bazooka Joe]

Federal tax credit only need to be 15 SEER 12.5 EER 8.5 HSPF for a split system Heat Pump as far as state rebates you would need to check.

I would consider a demand type defrost vs a time/temperature defrost, less defrosts typically. Do you have electric heaters in case your Heat Pumps breaks down ? Are they going to do a load calculation before recommending the size you will need or are they going to replace like for like tonnage and heater strip?

https://www.energystar.gov/about/federal_tax_credits

Rebates:

http://www.dsireusa.org/

[susanc]

[QUOTE=Bazooka Joey;23176491]Federal tax credit only need to be 15 SEER 12.5 EER 8.5 HSPF for a split system Heat Pump as far as state rebates you would need to check.

I would consider a demand type defrost vs a time/temperature defrost, less defrosts typically. Do you have electric heaters in case your Heat Pumps breaks down ? Are they going to do a load calculation before recommending the size you will need or are they going to replace like for like tonnage and heater strip?







Thank you, what units have the "demand" defrost? Which of what I listed do you recommend?

[susanc]

We have never had a frozen system.. We don't use electric heaters... Just bundle up.

Heat strips are 9-10 I think, it is what comes with systems. Replacing is 3.5 ton or 4 ton where .5 isn't available.

[Bazooka Joe]

As far as I know Trane , American Standard , Rheem, York have models with Demand Defrost and I'm sure other brands models as well.

No recommendation from me as to which brand model to go with, not much difference nowadays IMO no manufacture makes much of their own parts nowadays.

Off hand I Believe 1 KW gives you around 3400BTU plus change so a 10 KW heater gives around 34000BTU+

I do know a 10 KW heater @ 230v runs at 38-40 amprege which is a lot

[susanc]

Are you saying the lower end single stage 14 SEER is just as good as the variable speed bells and whistles models? I'm trying to get actual difference in how the home feels, energy savings, and balance that with cost of system.

[Bazooka Joe]

I suppose there are pros and cons of each type of system, better dehumidification with the variable speed, so I'm told , uses less energy with a higher SEER system another pro, bells and whistles complicated higher SEER units are nice, also more pricy, until they break, big bucks to repair once manufacture warranty expires, for the most part still have to pay labor thou, unless you purchase a extended labor warranty plan. Probably would need a Tech trained on that model of system due to the complexity. To me that offsets the savings over the years that you enjoyed from a less complicated lower SEER system if your concerned more about cost than better creature comfort with the higher SEER units. Again others will chime in and give you their recommendations, remember the installation and proper set up and sizing and correct duct work size and an occasional Preventive Maintaince check goes a long way in whatever system you decide on.

[susanc]

Thank you. Both companies are reputable. I agree about more bells and whistles possibly needing expensive repairs since labor is only covered for a year. Existing ductwork is fine (few small leaks will be repaired), both include a year service contract with 2 visits, plus any concerns about new unit and/or repairs. I'm just figuring out what you are saying about demand defrost, I suspect it will be on the more expensive systems, but I'm still trying to find out, by searching in internet land.

[Bazooka Joe]

Every time you go into a defrost your in A/C mode if you do not have or bring on part or all of your electric heat ( which tempers the air it really does not heat it ) and puts some strain on the compressor when it terminates a defrost , so if with a time/temperature type system as an example only it goes into defrost 3 times a day on that particular day your cooling your house down and the electric heat comes on, a demand defrost it may come on 1 or two times a day as an example , less defrost, less cold air, less electric usage, less strain on the compressor. Now you multiply that by your winter days, maybe living in SC you really don't need it.

[susanc]

Is demand defrost still automatic? So as needed rather than regular intervals? If I like everything else about a system, is it a deal breaker to not have it? Thanks!

[Bazooka Joe]

Is demand defrost still automatic? So as needed rather than regular intervals? If I like everything else about a system, is it a deal breaker to not have it? Thanks!

As needed instead of regular intervals, if you go with a higher SEER unit especially a bells and whistle chances are it may have some type of demand defrost system anyway. That's not a bad thing. Certainly not a deal breaker. I don't mean to confuse you

[susanc]

OK it looks like demand frost and dehumidify on demand are on higher end models, also I think the the variable speed handler has it somehow controlled thru a higher end thermostat. I've lived over 30 yrs. in hot/humid land and never had it, I'm processing.

We've eliminated the top 2 very expensive options, so there are 3 categories left to consider 1) standard just above builders heat pump, 2) a better single speed heat pump, 3) lower end 2-stage. In the middle of overwhelm and indecision... I'm leaning toward #2 but open for input, so.... do you or anyone have opinions on these:

Trane XR13/14: I've heard good about 13, bad about 14 but these fulfill #1 above

Trane XR15/16 XL16i: These are nicer single stage, better SEER, seems like XR15 is the best price and rest are not a lot better in efficiency, wondering whether to get single speed handler or variable since a lot of variable features can't be accessed with a single speed conpressor, and how much energy efficiency is lost by getting single, for #2. Carrier guy did not quote me on a single speed, he pushed 2-stage or above only.

Carrier Performance 16/Trane XR17: fulfill #3, we've all but taken XR17 out because of cost and not that much better numbers than XR15, but I'm not sure about putting variable handler with single speed and want to see numbers for XR15 with single handler. The Carrier is the only other 2-stage quote I have.

What improvements would I get in a nicer single speed over what I have now?

[susanc]

Adding that I have just realized there are multi-speed and variable speed air handlers, sorry for assuming all non single-speed are variable...

[susanc]

Anyone?

[tigerdunes]

As said, you get the proprietary top and extra 2 yrs on compressor warranty with the XLi condenser series. If you don't have snow storms or lots of trees, I would not pay extra for the XLi series. I would want a 3.5 ton sgl stage XR16 HP or 4 ton two stage XR17, both with best matching var speed air handler. If going with 4 ton XR17, ductwork both supply and return should be looked at as far as the extra CFMs. Also, you might need a new and correct sized refrigerant lineset. I would want a filter cabinet like Trane's Perfect Fit and XL824 thermostat set up for dehumidify on demand in AC cooling mode. For your location, with moderate winter climate, probably a 10 KW heat strip. You should be aware that both of the models I listed are available through sister company Am Standard dealers, identical except for cabinetry and badging.

IMO