Trane XL19i with XV90 furnace matching issue

[OOC]

House - 1500-2000 sq ft, single story older home near Greenville, SC

The contractor I selected out of 4 has given me 2 options for a split, dual fuel system to consider.

XL16i 3-ton heat pump with XV90 80,000 BTU furnace

OR

XL19i 3-ton heat pump with XV90 100,000 BTU furnace (with 5-ton coil)

2-questions:

1. The contractor explained that the XL19i needs the bigger furnace, not for the BTU rating, but because it needs the bigger coil on the 100,000 BTU furnace. Both systems are 16 seer (the XL19i rating is decreased to 16 (according to the contractor) due to it being a heat pump and not an AC only unit).
These guys seem real knowledgeable, the service guy that I used for my existing system to be replaced is really thorough and helpful. I have no doubt about their credibility. They've take nthe time to inspect my home, did load calcs, and sat down with me to discuss options. I just wonder if I'm missing something obvious.

2. I like the dual compressors of the XL19i, but is it worth the approx $1,400 more than the XL16i? I know it will use slightly less electricity when using it's smaller compressor than the low-speed stage of the XL16i, but will I see a benefit in savings and/or comfort during the lifetime of the unit? Especially now that the SEER ratings are the same on the system's quoted for me?

[mchild]

Did the contractor provide you with model numbers? If so, please post them.

[OOC]

He did show me model numbers, but after he left I realized that he took that sheet of paper with him. I believe this was an honest mistake because we were both looking at them and he was showing me information from the Trane equipment specifications book- I could have easily written them down myself.

From Trane's site and based on the info he gave me, here's what I think the model numbers are

for the 3-ton XL16i with 80,000 BTU XV90 furnace
4TWX6036A and TUY080R9V3W (maybe it was the downflow horiz- not sure but it's going in a crawl space with the ductwork)

for the 3-ton XL19i with 100,000 BTU XV90 (with 5-ton coil) furnace:
2TWZ9036B and TUY100R9V4W

[tigerdunes]

OCC

I have a Trane dual fuel and also live in the Upstate SC.

Several questions.

Tell us about your home-type and number of windows and home's insulation qualities in ceiling, walls, and floor. Also what is size and type of equipment you are replacing.

The equipment you are looking at is first rate and Trane has a seamless dual fuel set-up between heat pump and gas furnace.

Has a Man J heat/cool load calculation been performed to correctly size new equipment? If not, insist upon this and get this in writing. You should also have your ductwork inspected.

Here are my thoughts. Forget the XL19i and go for the XL16i-the 16i has a better balance of SEER and HSPF rating for our area/climate. I would also drop down to the 80 KBTU XV90 or even the 80 KBTU XV80 which provides plenty of BTUs for those cold days in Greenville. I would also include a good media filter cabinet.

Unless you just want gas backup, I really think it is overkill for our area. This past winter, I only used about 60 therms of gas as backup. Nat gas will only get more expensive and I expect electric rates to be more stable. Just a thought to consider.

IMO

[OOC]

House info:

-Single story brick ranch,
-appr 1900 sf, but minus internal walls, closets, cabinets, etc it's around 1550
-17 windows, 3 3' x 3', rest 3' by 4'4"
-House built in late 50's or early 60's.
-6-9 inches of insulation in attic (3-4 blown in, and roll sheet battens on top)
-3-4 insulation (battens) in vented but closed crawl- but lots of gaps there.
-Attic unfinished,
-hip-roof, dark shingles,
-6 rabbit-holes (no turbines) and soffitt vents- no ridge vent (yet).
-In July/August attic reaches 140F by late afternoon (measured).
-Most of house is hardwood floors.

I currently have a package GE Weathertron 3-ton unit (all electric, no gas) model number indicates it was built in late 60s.
It cools the house off great (expensive though), but is now leaking freon from the coil. In the winter, when charged, it rarely went to backup heat which also makes me question the need for gas. With the twins (infants) in the house, I thought gas might be nice as well.
Also, while our existing system seldom went to backup heat except really cold days, the house always felt cool and not cozy on thosedays. "Throw on another sweater" wasn't a solution my wife liked.
If I cranked up the thermostat too much, I knew my power bill would push close to $300 in the dead of winter (it's 250-260 in the dead of summer).

Re: Manual J
Of the 4 contractors, 2 did it- they both took detailed measurements of the house, windows, insulation, etc. (one went room by room). The other two measured outside footprint and checked insulation only. They said they were not doing the calcs. I bought the residential version (2 month lease) of the HVAC-calc provided at the link above and did the calcs myself (admittingly I'm no expert). I come up with a cooling need of around 28,000 BTU (Latent heat appr 4,800 BTU- setting the humidity desired to 50%- althoguh I hope I get less than that in the summer) and heating need of around 40,000 BTU. The contractor I like (did the calcs) recommended the 3 ton XL16i or XL19i with the XV90 furnace (80,000 BTU for the XL16i and 100,000 BTU for the XL19i). He claimed the larger furnace is needed for the XL19i because the XL19i needs the larger (5-ton) coil in the larger furnace, not because of the heat need. I don't have any reason to doubt him and he said the technical staff at Trane agreed with his selection. I just want to know what I'm missing. Why does a 3-ton XL19i need a 5-ton coil in the furnace.

[tigerdunes]

occ

I see where you pulled the trigger on a new Trane dual fuel system. If installed correctly, you will be very pleased.

I still believe dual fuel is overkill for the upstate. The XL16i HP with appropriate var spd air handler gives higher SEER and HSPF than dual fuel. However, if you are already using nat gas for cooking and/or hot water heating or just have a better comfort zone with gas backup, then your decision is fine.

Probably the biggest surprise you will have is the quality/comfort of the heat pump in heating mode as compared to your old GE 3 ton package unit which obviously at its age has done its job. As different as night and day. Other pluses will be better dehumidification in AC mode, quiet operation, better room to room temp constantcy, improved air quality if equipped with a good media filter cabinet. And finally you should notice a significant reduction in cooling/heating bills.

I would have your installing dealer set changeover from HP to gas and back at around 32 degrees. Then you can adjust up or down based on family's comfort level. Get your dealer to show you how this is done.

Unless you have plans to re-roof, I would have a power ventilator thermostatically controlled to pull hot air out of attic in summer.

Let us know how install goes and your initial impression after start-up.

IMO
GoodLucK!

[beenthere]

If the 19i's SEER drops to 16, then you won't save over the 16i in cooling.
Check the HSPF.

[OOC]

You're right. That's why I got the 16i instead of the 19. SEER is the same on the setup, but the 16's HSPF is better than the 19's and the 16 is cheaper.

Tigerdunes - regarding the attic power ventilator- I've read in several places (hadn;t searched this site though) that the electricity you use in running the power ventilator negates savings on electricity from the ac running less. I haven't looked at the numbers in terms of KWh needed to run the fan to X hours per day, but I did look at the numbers regarding a cooler attic. A cooler attic does greatly save AC power portion of the bill. I don't have near enough soffit vents, so that's on the to-do list in the near future when I scrape and paint my soffits and trim.

[tigerdunes]

OCC

BTW, perhaps I overlooked it, but what did you decide about model of stat and air cleaner cabinet?

And with the hot week approaching ,how long will install take-two or three days?

TD

[OOC]

Trane XL803 thermostat.

I decided against an air cleaner. I've got a dog and a not-so-tight-house. We love to open windows weather permitting. With no one in the house having allergies or asthma, we decided that was an expense we didn't need to worry about. Plus, we probably have 2.5 times the return capability than we need (3 large returns) so I don't know if I'm super worred about the 3 high quality pleated filters starving the system for air. I'll ask the installers to check head loss in the system to make sure. I see how much dust those 3 return filters get now every 2-3 months when I change them. I just didn't believe that I'd be able to wait 6 months between servicing a whole house filter, EAF or not. I'm not saying the installers claimed 6 months between service, but I think Trane literature does. The contractors were all up front about their thoughts on the system, whether for or against, but none of them guaranteed at least 6 months between cleaning the Clean Effects.

[tigerdunes]

ooc

any update on your install?

is it complete?

any comment on your new trane system?

td

[BaldLoonie]

Sure doesn't sound like you need any 100K 90% for that house. Around here, and we get much colder, you might get a 60K even. Looking at the ARI ratings, he can use the 80K furnace and 060 coil. He would have to make a neat little transition to the wider coil. But if he can't do that... he might recommend the huge furnace.

BUT, I'm with tiger, 90+ won't pay for as little as you'll use it. Unless you want gas in the house for other reasons, I'd stay all electric. Remember you pay a healthy fee (often $15-20 a month) just for the pleasure of having a meter then you gas is on top of that. The electric furnace is cheaper than a gas furnace, plus the cost of gas piping, new flue, etc.

Forget the 803, get the Vision Pro IAQ. Many more features such as dehumidify on demand and staging of the backup. If you buy a XV, why cripple it with the timer for staging.

[hvac hero]

He would have to make a neat little transition to the wider coil. But if he can't do that... he might recommend the huge furnace.



Thats exactly what I thought when I read it too. About a 8 inch transition to open it up to the bigger coil & it'll also give you a spot to check static pressure.

Off the subject, everybody has their preferences & I know a lot of the ones on here love dual fuel. I prefer straight A/C with a 90 plus furnace. Even with high gas rates, my bills are never that much with the high efficiency furnace.

Also, what kind of filtering system are they putting in? If IAQ is important to you, Trane has the "Clean Effects" that is nice. At the very least, I'd go with a standard 4 inch filter.

[tigerdunes]

for forum members

ooc went with dual fuel XL16i 3 ton hp paired with XV90 2 stg 80k

TD

[OOC]

Tigerdunes is right - I went with the XL16i 3 ton HP with XV90 80 BTU gas furnace. (I'm in Upstate SC) I understand that I'll likely never use the gas furnace enough as compared to the HP to justify the XV90 (or even a gas furnace period), but I liked the options it gave me. For one, if the power goes during our notorious ice storms, all I need is to supply 120V to the gas furnace to have heat for the kids (now babies). Next, I'm an engineer and would like to fool around with what's most efficient at what temperature. I check my electrical meter daily and also record hi&low attic temps, outisde temps, inside temps to see what I'm doing around the house compared to the outside weather is making a difference.

I'd like to see some curves from Trane to see where the HP's energy usage is less efficient than the furnace, but so far I only have folks' opinion (which I do value) about what temp they like the switch to gas to be. Sure, I could have bought the XV80, but the price difference wasn't huge based on some quotes I got from other contractors.

For the record, on very similar weather days (cloud cover and cooling degree days), the KWh usage has been hovering around 26 KHw per day versus the 40's I had last week before the change to the new system. This is way too small of a dataset for me to sing the praises of my system, but it's not too shabby either.

With regards to the 803 stat- yes, I did my research and realize that there are better stats out there that could better manage my system's full capabilities - not too mention track KWh usage, but I also saw the $600 rebate from Trane for picking the stat I did with the system I did, so I took it. In the last few days my humidty when I'm home (and the stat's program is set to cool to 76) has been steady in the 30-40% range. With hardwood floors, I'm not crazy about the humidity being too much less than that. I did look at a Carrier system from a very knowledgeable and friendly contractor, but my previous system was a GE Weatherton and workled with little problems for 38 years, so Trane's Weathertron line they bought from GE automatically had my initial attention.

[kevinmac]

The XL19i 3 ton is the 19 SEER unit with the TWE040 airhandlers, it's when you go to the 4 ton and 5 ton units with different AHs the SEER falls off, just like other manufacturers. If you need a condensing unit with furnace, TXC036-17.50SEER, TXC037-18SEER, TXC054-18SEER, TXC037S3-18 SEER

With that said being where you live the XL19i may be overkill since it really does a very good job with humidity. Lower humidity may not require a unit like the XL19i. So you may see quicker payback withthe XL16i.
So in your case the XL16i may be very adequate for your location.