Help choosing Heat Pump in Florida – Load Calc from Online Source

8 years ago

I have a small 60 year old beach house. My current installation is a 14 year old 2 ton
12 SEER Rheem that no longer functions.
I have had the same 2 ton capacity for the last 25 years. All the contractors are trying to move me up
to more expensive 2.5 ton. It’s a small
job and I’m having problems getting load calculations from the contractors. I got
an email response from one saying the calculations suggest a 2.3 ton, but no
actual documents. I do know that when talking
to the estimator about a load calculation, I found out his software had no
provision to account for things like a 6’ wide canopy over most of my south
facing windows. I tried the online load
calculator, but I’m not sure I’m getting even close to a correct measurements.

The literature on most of the 2.5 ton units suggest they
will get 1% -2% loss due to the current size of my line set being 5/8 instead
of the 3/4 recommended for the 2.5 ton units.
No contractor has suggested changing the line set, but I understand that
can be expensive and wonder if it is necessary to do the job properly? Is this
something to consider and will it affect the performance of the unit over time?

I have some space constraints as the air handler is in an
old furnace closet and a larger unit may need to have some extra access
installed. One Bryant dealer told me I
needed to install a pump because of the space available and the size of the 2.5
ton unit. I’ve never had a pump before,
but I do know the sound is irritating and the closet is near the living room.

I also wonder about noise as the fan on the 2.5 tons seem to
operate at almost 50% more RPM’s than the 2 ton.

I don’t like going high end on HVAC because I don’t think I
get a return, I’m satisfied with a 14 SEER, 11.5 EER. I think that’s all I
need. Things don’t last too long in this
environment and after about 10 years it seems that the efficiency really starts
to decline. Even more expensive units
seem to suffer. My understanding is that true variable speed units (sorry if
the nomenclature is incorrect) are available in high end units and should be
the norm by the time this unit needs to be replaced in about 10 years. I would like to install a 14 SEER, 11.5 EER
with a 5kW Heat Strip (30 Amp Circuit) in 2 ton now and spend the money on the
next install when the tech catches up.

I’d like to know if you think my estimate of replacing the
A/C every 10 years in this environment is reasonable, if you think I should
stay with a 2 ton or move up to a 2.5 ton, if I do replace the units about
every 10 years if staying at the less expensive range of installations is more
practical and some recommendation on equipment (14 SEER, 11.5 EER with a 5kW
Heat Strip (30 Amp Circuit). I know the
installer is critical, but some of the best ones seem to use ICP products for
their less expensive installs, do any of you have any thoughts on those
products?

These are the results I got from the online load
program. That program didn’t have a
provision for block walls (I used brick with no insulation) and had no
adjustment for shading on the south wall.

I used, Brick with no insulation, Concrete Block on Slab, 1,150
as the conditioned square feet, 9,250 for cubic feet, Average Construction,
Attic Ductwork with R-6 insulation and Good for duct tightness. The paperwork for the ductwork doesn’t have
an R Value, so I used R-6 as it was only two years old. I used good for duct tightness even though
when a previous duct system was tested I was told the building was almost too
tight. I could not adjust the shading to
represent the canopy on most of the south exposure. All of the glass is Low-E with blinds, vinyl
clad, Miami-Dade hurricane rated. I have
two doors with dual pane inserts, one facing north and one south under the
canopy. The canopy is 6 feet wide and
covers all but one of the south facing windows.

Total BTU’s Cooling:
18,266

Sensible Load: 16,075

Latent Load: 2,191

Total BTU’s Heating:
15,408

Thanks to Gary for Providing the online load calculator at http://www.loadcalc.net/

Featured Answer

tigerdunes

8 years ago

I would stay with 2 ton and go with Trane or sister company Am Standard mainly because they hold up better in harsh coastal environment. 10 yr life maybe on a low end system. You should want 15 SEER minimum with either var speed air handler or high eff air handler non var speed. I can make specific suggestion if interested.

IMO

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Comments (10)

mike_home
8 years ago
If the the 2 ton unit was able to keep the indoor temperature at 75 degrees then that is the correct size. You live in an area of high humidity so being slightly undersized is a far better situation than being over sized.

You need to buy a heat pump that is made for a coastal installation. Trane/American Standard, and Carrier/Bryant have some available models. I am not sure how much benefit a variable speed air handler will provide with a 2 ton heat pump. It may raise the SEER/EER values to a level where you qualify for a local utility rebate. This could offset most of the additional cost. It is worth investigating.
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User
Original Author
8 years ago
Thanks for the advice. I was just told by an installer if I went with a 15 SEER I would need a 3/4 line set, if so more cost. I am really constrained for space and many of the air handlers on the 15 SEER units are too tall. One exception is Rheem where the air handlers are the same size for 14 & 15 SEER. I don't want a pump, have had too many friends with them have bad experiences. The rebates are only $150 so not much help. I can't make the current opening larger because of built-ins above it, the other choice is cutting out a section of my bedroom. I guess it's back to the drawing board. Thanks for taking the time to answer.
tigerdunes
8 years ago
You are being given incorrect advice. Line sets are sized according to brand and size of system, certainly not SEER. Find out what size your existing lineset is. Usually, not always, if you are staying with same size condenser as old, then existing lineset should be fine depending on condition and will need to be properly flushed. Not a big deal for experienced HVAC dealer.

do I understand you now want to go with straight AC, not a HP? I was just going by subject title of your thread. I would not go with Rheem.

i am done here.

Good Luck

IMO
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User
Original Author
8 years ago
Thanks again, I've been given a lot of bad advice by installers in my area it seems, starting with sizing. Sorry about the confusion, I was talking about a drain pump, I would prefer not to have one. I'm staying with a HP for the installation. I'll check on the brands you suggested.
tigerdunes
8 years ago
last modified: 8 years ago
7416099 ActiveSystems TRANE XR14 TRANE 4TWR4024D1 *AM7A0A24H21 725 23000 12.00 14.50 21800 8.50 13000 1HRCU-A-CB 201522

Same available from American Standard dealer ...
User thanked tigerdunes
User
Original Author
8 years ago
Tigerdunes, I just did did a search on the combination you suggested (cut and pasted the exact set of characters) and found a post by you on another site:

http://hvac-talk.com/vbb/showthread.php?1714911-Trane-XR14-Variable-Speed-vs-XL15I-Variable-Speed

Has your opinion changed on the XR14 and do you still recommend this combo:

6059613 Active Systems TRANE XR13 TRANE 4TWR3024D1 *AM7A0B30H21 770 25600 12.00 14.50 23000 9.00 15000 1 HRCU-A-CB 219 552
mike_home
8 years ago
I am confident you can achieve a 15 SEER with a 5/8" line set. However I would not spend a lot of money to go from 14 to 15 SEER. You will never see the ROI.

I don't understand the comment about not wanting a drain pump. How to you plan to remove the condensate when the AC is running? It needs to be a either drain connect to the plumbing, or a condensate pump.
User
Original Author
8 years ago
Mike, I currently have a drain line and would prefer not to have the pump. Thanks for the advice on the 14 vs. 15 SEER and the variable speed air handler, I appreciate you addressing the ROI. I just got an estimate on a Bryant 214DNA024 with a front draw FFMANP025 that will fit my limited space. What do you think about that system? It seems a lot of past Trane dealers in the area have dropped the product because of warranty issues (getting timely help from the company)
mike_home
8 years ago
If the drain works, then there is no need for a condensate pump. Who somebody trying to sell you a pump?

I did not see a response as to whether the 2 ton AC kept you cool in the summer. What temperature do you set the thermostat? How is the humidity level?

The Bryant 214 is part of the legacy series. I would rather see you spend a little more money and get something from the Bryant Preferred series.

Trane makes a very good heat pump and from everything I have read would have no hesitation to buying their equipment. Many warranty problems are due to bad installations which seems to be common in Florida. Trane may have refused to honor warranties where the equipment was improperly installed.

Tigedunes knows heat pumps. So I recommend you consider any of his recommendations. Consider all options, but the decision may come down to your budget and the size of the closet. You also need to find a contractor who know how to install a heat pump properly. Some of the comments you have posted so far makes me suspicious.

Help choosing Heat Pump in Florida – Load Calc from Online Source

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