Utter heat pump confusion - Carrier & Lennox

[CarrieW]

Hi all,

We're in the process of replacing our heat pump and are having a really hard time making comparisons or finding independent information. Everyone we talk to gives us a different answer!! I've pasted the details of the bids we've narrowed it down to plus details about the house and here are our key questions:

1. How do you decide between 2.5 or 3 ton? No one wants to do manual-J, guy with 3-ton would install extra return
2. Does anyone have strong feelings about Carrier vs. Lennox?
3. We're getting mixed messages on whether or not to replace the humidifier. Some tell us with the newer system we don't really need it, others say we should do it. Our house isn't really noticeably dry in the winter - are we OK without it or will that change with the new system?
4. Is it OK to just flush the lines, or do we need to get a new lineset?
5. Is it worth getting a larger indoor unit to increase SEER?

Any general thoughts about the proposal below (all are roughly the same price)? I know this is a slew of questions, thanks enormously for your help - this is all very confusing!!

House
- Approx 1800 ft2 on two levels plus finished basement
- Pulling out 2.5 ton York that never worked real well
- All bids include new slab, new disconnect box, flushing of old lines

Proposal 1
- Carrier 25HNA636 Infinity heat pump
- Carrier FE4ANF002 air handler (15 kw)
- Carrier CCUIDO1 Infinity control
- 15 SEER, 2-speed system
- No humidifier
- 2 years labor guarantee


Proposal 2
- Carrier 25HNA636-3 Infinity heat pump
- FE4ANF002 air handler
- Infinity control
- Honeywell bypass HE265A humidifier
- EZ trap safety switch
- 1 year maintenance

Proposal 3
- Lennox XP15036 15 seer (3 ton)
- CBX32mv036 air handler
- Honeywell 7000 thermostat (L7742U)
- April Air 400 humidifier
- April Air 2200 filtration system
- 1 year labor ($750 more for 10-years labor) included
-

[gary_g]

What State do you live in?

[RyanHughes]

1. Since you mentioned the 2.5-ton York wasn't working well, it's quite possible a 3-ton unit is necessary, but you can't be sure without a load calculation. The fact that they are concerned about having ample return air is good.
2. I'd put more emphasis on the contractor--both should be quiet, reliable systems, but the Infinity system gets the nod for more control over indoor comfort.
3. Might not be a bad idea, but is it necessary? Probably not.
4. Flushing the lines is fine and often done. Replacing the lineset just isn't feasible in many cases, but when it is, I'd sure prefer it. Make sure they give them a good flush. Might not be a bad idea to ask the equipment manufacturer for reassurance.
5. YES. I have no idea why they even quoted the FE4ANF002 unless you were short on space. The *005 would get better efficiency and capacity for that system. Using the *002 is just hampering the efficiency and capacity of the system.

[Old Lennox]

Hi all,


- Pulling out 2.5 ton York that never worked real well
-

I am just a homeowner but I think you answered your own question above. Why do you say 2.5 ton never really worked well? Did it fail to maintain set point temperature even after being serviced and determined to be running ok? This would be a good indication that 2.5 ton was not enough. As others will tell you shortly if you upgrade to 3 ton there is a good chance that your duct work will not be sufficient.

I think a manual J is very important but past experiance should play some role.

[gary_g]

25HNA636 condenser with FE4ANF002 air handler:
33,600 btu cooling (36,000 btu is a full 3 tons), 11.5 EER, 15 SEER, 33,800 btu heating at 47F, 8.5 HSPF, 18,900 btu heating at 17F

Same condenser with FE4ANF006 air handler:
35,800 btu cooling, 12.6 EER, 16.5 SEER, 34,200 btu heating at 47F, 9 HSPF, 19,100 btu heating at 17F.

The Carrier Infinity is a dual-stage compressor system.

XP15036 condenser with CBX032MV036 air handler:
34,800 btu cooling, 11.5 EER, 14 SEER, 31,400 btu heating at 47F, 8.7 HSPF, 19,700 btu heating at 17F.

The Lennox XP15 has a single stage compressor. This match-up is weak on heating btus at 47F for a 3-ton system, but is better at 17F than the Carriers.

Good luck.

[phosgene]

"Pulling out 2.5 ton York that never worked real well"

Why? This is the number one question.

[dash]

Your 2.5 ton may not have worked well,due to undersized ducts,if so adding a half ton will require more air flow,in an already undersized duct system.

Load calc would be a good idea,however the two stage systems aren't made in the 2.5 ton size.

[tigerdunes]

Carrie

920075 Active OEM XP15 SERIES LENNOX INDUSTRIES, INC. XP15-036-230* CBX32MV-036*+TDR 34800 11.50 14.00 31400 8.70 19700

Throw the Lennox overboard. The system configuration is very weak and short on both heating and cooling BTUs-a big negative.

1. You need a load calculation to accurately size a new system. I would not go lower than a three ton but your ductwork needs to be sized correctly both for supply and return.

2. Carrier over the Lennox. The XP15 is a sgl stg condenser and is built more for quiet than good performance numbers. Too bad for Lennox.

3. The question of a humidifier is up to you. If your home has not been too dry in the winter and you don’t have problem with static electricity, dry skin, or cracking furniture, then I would say you can do without.

4. I prefer that new refrigerant line be installed. Keep in mind you will be changing refrigerants as well as most likely needing a different size which is important in making your new system to run up to its potential efficiency.

5. Yes, if you have the space so that you can increase the system’s performance metrics. Depending on where you live, I like a new HP system to have the following minimum numbers:

15 SEER,12 EER, 9 HSPF
Full BTUs for your size both in cooling and heating mode
Var speed blower, R-410 frig, scroll compressor
Electronic demand defrost preferred over timed defrost
A thermostat that will control var spd blower for superior dehumidification in cooling mode.

You can select Carrier's sgl stage Performance 15 model with Infinity controller and save yourself some change. Yes, you may lose a little comfort and operating efficiency but the overall performance numbers are just as good as the Infinity 16. See below for a great system configuration.

1125689 Active OEM PERFORMANCE 15 PURON HP CARRIER AIR CONDITIONING 25HPA536H30 FE4ANB006+UI 36000 13.00 16.00 36000 9.30 21800

1250404 Active OEM INFINITY 16 PURON HP CARRIER AIR CONDITIONING 25HNA636A30 FE4ANB006+UI 35800 12.60 16.50 34200 9.00 19100

1250416 Active OEM INFINITY 16 PURON HP CARRIER AIR CONDITIONING 25HNA636A30 FE5ANB004+UI 35800 12.60 16.60 34400 9.00 19100

taken from the CEE HVAC directory

Another brand/sgl stg system that has good numbers are Trane's XL15i heat pump and Am Standard's Heritage 15.

IMO

[CarrieW]

Thanks for the replies, so far!

In answer to the previous questions - we're in the state of Maryland and we're replacing the system because it has completely died (it's pretty old) and doesn't seem worth repairing.

[RyanHughes]

In Montgomery County by chance? Gary and I are Marylanders, too (I live in Montgomery County). :)

Both Lennox and Carrier are running rebates, now. I know the Infinity has a $1000 rebate (at least), and I see Lennox has a $1200 rebate (though I'm not sure what systems it applies to). Are you aware of these? Trane has some rebates as well.

[gary_g]

Wow. 3 Maryland homeowners in one thread. Governor O'Malley may tax this thread if he sees it :)

Carrie:

You may be getting lost in all of these performance numbers that Tiger Dunes and I are quoting, but Tiger did do his homework and came up with a single stage (you don't need dual stage) heat pump Carrier Performance 15 Model# 25HPA536H30 matched with a FE4ANB006 air handler. This system provides outstanding performance numbers and should be less costly to buy than the Infinity 16.

For lowest operating costs in the summer, you want a system that has a 12 EER minimum, regardless of SEER. The match-up that Tiger quoted has an EER of 13 which is outstanding.

I would ask your Carrier rep for a quote on that system.

You also need to verify that your ducts can handle a 3 ton system.

Good luck.

[RyanHughes]

A dual stage may not be a terrible idea--we can get some high humidity in the summertime. A correctly-sized single stage unit can dehumidify well as well, though.

[gator8]

Wow. 3 Maryland homeowners in one thread. Governor O'Malley may tax this thread if he sees it :)




That's why we call him Owe Malley.

[beenthere]

If your duct system is too small for a 2.5 ton, then it will be too small for a 3 ton.
If you duct system was sized properly for 2.5 tons, then it will be undersized for 3 tons.

Its best if they do a Manual J (many companies won't) to determine what size you need. Nothing wrong with going the next next up on a heat pump. But the distribution system must be sized for it, or modifications made to improve air flow if you want ot get anywhere near the efficiency rating.
Adding a return will help, but the supply side must also be large enough.