Pros & Cons of Trane XL20i Versus XL16i Heat Pump

[vstech]

bump. to make sure you notice my post above, since we posted at the same time!

[Florida Joy]

1800 lb gorilla- what's duct ESP at 1600 cfm.

Also, can't maintain or can't recover? You set n forget, or jerk throttle around like an epillectic bus driver? Seems a small distinction but is a BIG difference.

Sorry, but I don't follow your comment about 1800 lb gorilla. What are you trying to say?

I do not know what the ESP is for my ductwork. I do know the existing 20x20 air return is inadequate for my existing 3.5 ton Rheem condenser with the existing 4 ton Rheem single speed air handler. I know it tries to suck the air filter into the air handler even when it's fresh and clean.

My t-stat is an older model and the only user adjustment is temperature. I set it and forget it at 75. Until last Wednesday when they fixed the leaks in the outside copper and replaced the accumulator, and I also had the ducts sealed and R30 blown in, the existing unit ran constantly and would not "maintain" the 75 degree t-stat setting.

[54regcab]

Keep in mind that it's seriously doubtful that the current system is actually delivering 3.5 tons. A bad installation can cut capacity by HALF. The 3 ton XB14 is what I'd go with, properly installed it should do the job. That's about 600sq ft per ton which isn't unreasonable if your house is decently insulated. If 3 tons isn't enough at first then fix the house to the point that 3 tons will do the job.

Manual J calculations are great if they are done right. However some contractors tend to fudge input numbers to get the result they want. It's not a coincidence they are all ending up with 3.5 ton like you currently have.

[Florida Joy]

bump. to make sure you notice my post above, since we posted at the same time!

Thank you. Yes, I did see your post.

Between yesterday and today, I've noticed something with my existing system that may help me decide to wait awhile before investing in a replacement.

On Monday, I had the ducts sealed ($125 after FPL rebate). On Wednesday, I had R30 blown in ($300 after FPL rebate). Wednesday afternoon my home warranty company had a repair tech replace the leaking accumulator (he'd repaired the leaking copper the week prior, but had to order the accumulator). The A/C repairs cost me $75 total (my home warranty deductible). On Friday I had my irrigation/pump guy cap off the sprinkler head that was 2 inches from the condenser. Yesterday I went to Lowes and bought a small digital thermometer that also measures humidity, and keeps track of min/max readings over time.

What I've discovered is that the temp at the t-stat is actually 77, not 75, when the unit cycles on/off. Also, the unit is now cycling on/off as it should, all day long... even when it's 88 degrees outside with 75% humidity, like it is right now! I'm pretty comfortable right now and the actual temp/RH throughout the house is holding at 77 degrees/40% RH.

I think I'll keep a watch on the electric and see if it comes down to a reasonable level. I do understand my 12 y/o Rheem has the bottom falling out, and I might have to put out another $75 now and then for repairs, but I may be better off just keeping the old system another year or two until my 401k recovers enough to pay for a new XL20i.

What do you think?

[beenthere]

Prices are not allowed. Not even price differences.

[Florida Joy]

Keep in mind that it's seriously doubtful that the current system is actually delivering 3.5 tons. A bad installation can cut capacity by HALF. The 3 ton XB14 is what I'd go with, properly installed it should do the job. That's about 600sq ft per ton which isn't unreasonable if your house is decently insulated. If 3 tons isn't enough at first then fix the house to the point that 3 tons will do the job.

Manual J calculations are great if they are done right. However some contractors tend to fudge input numbers to get the result they want. It's not a coincidence they are all ending up with 3.5 ton like you currently have.

I understand how contractors might fudge to "sell" to a homeowner's expectations... current system 3.5 ton... going to 3 ton might be perceived as reducing comfort or increasing runtime (i.e., energy consumption). However, when you take into account the square footage of my sliding glass windows (364 sf) plus the 350 sf of living space that's uninsulated (open beam ceilings, 14 ft high), I don't think 3.5 ton is oversized.

[Florida Joy]

Prices are not allowed. Not even price differences.

Sorry... won't happen again.

[tedkidd]

I do know the existing 20x20 air return is inadequate for my existing 3.5 ton Rheem condenser with the existing 4 ton Rheem single speed air handler. I know it tries to suck the air filter into the air handler even when it's fresh and clean.

Undersized duct and filter drop. Not getting 3.5 ton of cooling, might be closer to 2.5. Serious duct improvements need consideration. 3 ton may avoid this need.

On Monday, I had the ducts sealed ($125 after FPL rebate). On Wednesday, I had R30 blown in ($300 after FPL rebate).

So you experienced first hand that improving the home reduces worst case load.

Since duct is undersized, (more so now that its been sealed) there is a severe energy cost penalty. Imagine MPG if driving your car with emergency brake 1/2 way on.

the unit is now cycling on/off as it should

As it should?

No. Equipment shutting off when beyond worst case temperatures means oversized. Ideally equipment never shuts off during meat of season load conditions.

Sounds like 3 ton 2 stage communicating will get you there. Comfort, noise, and cost savings will be very gratifying.

I may be better off just keeping the old system another year or two until my 401k recovers enough to pay for a new XL20i.

What do you think?

I think about now you are feeling overwhelmed, and looking for excuses to do nothing.
I think equipment will be more expensive in 2 years, if you wait the replacement won't conveniently occur when significant mfr incentives are available.
I think there will be less in your 401k, not more.
You'll regret these things, and the $4-800 in energy savings you WONT have. That's what I think.

[Florida Joy]

I understand how contractors might fudge to "sell" to a homeowner's expectations... current system 3.5 ton... going to 3 ton might be perceived as reducing comfort or increasing runtime (i.e., energy consumption). However, when you take into account the square footage of my sliding glass windows (364 sf) plus the 350 sf of living space that's uninsulated (open beam ceilings, 14 ft high), I don't think 3.5 ton is oversized.

FYI, most of the homes in my lakefront neighborhood were constructed in 1980 and a majority are the same design as mine... lots of windows to to take advantage of the lake view with an open beam family room... and with a 150sf screen room later converted to conditioned space by the homeowner... total of 1827 sf. All were built with 3.5 ton systems and my close neighbors currently have 3.5 ton systems as replacements, including the one who just put in the XB14 two doors down.

[tedkidd]

Because your neighbors are doing it, it must be correct? I hope you didn't think about that before posting.

[Florida Joy]

Because your neighbors are doing it, it must be correct? I hope you didn't think about that before posting.

No, that doesn't make it correct, I posted it as information only, not as justification for a decision I have yet to make.

As I said in an earlier post, I'd like to discuss with my potential contractors the possibility of going with a 3 ton XL20i. Can't you tell I don't have my mind made up yet? So much to consider and I'm trying to learn... let the buyer beware has been my motto for half a century... I don't trust half of what people tell me when they're trying to get my money.

[Florida Joy]

Undersized duct and filter drop. Not getting 3.5 ton of cooling, might be closer to 2.5. Serious duct improvements need consideration. 3 ton may avoid this need.



So you experienced first hand that improving the home reduces worst case load.

Since duct is undersized, (more so now that its been sealed) there is a severe energy cost penalty. Imagine MPG if driving your car with emergency brake 1/2 way on.

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FPL and contractors have crawled in the attic and looked at ductwork and told me it doesn't need to be upgraded. On the other hand, everyone has told me the one 20x20 return air grill is inadequate.... I'm told a minimum of 144 sq inches is required per ton of cooling. I get that and agree I need to add another return air grill... that's easy... add another in the wall around the corner from the existing inlet and both will feed the a/h that sits on a platform in the corner of my laundry room.

Don't know how to verify the adquacy of the ductwork without help. So far, my "help" says the ducts are OK.

As it should?

No. Equipment shutting off when beyond worst case temperatures means oversized. Ideally equipment never shuts off during meat of season load conditions.

Sounds like 3 ton 2 stage communicating will get you there. Comfort, noise, and cost savings will be very gratifying.

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I didn't mean it was cycling on/off during the hottest part of the day. It's not.... it's running non-stop at the moment. What I meant was in the morning before it gets real hot outside and in the evening after it cools a bit outside, it's cycling on/off. Before the repair it wouldn't shut off at all until 2/3 o'clock in the morning. Then when the sun came up, it never shut off even once.

I think about now you are feeling overwhelmed, and looking for excuses to do nothing.
I think equipment will be more expensive in 2 years, if you wait the replacement won't conveniently occur when significant mfr incentives are available.
I think there will be less in your 401k, not more.
You'll regret these things, and the $4-800 in energy savings you WONT have. That's what I think.

[/FONT][/COLOR]

Overwhelmed? Probably.
Looking for excuses? No, I don't think so. More like weighing and deciding between my options.
More expensive in 2 years? Probably.
Mfg rebates not coinciding with delayed replacement? Could be, but I do have a home warranty to patch the system until the time is right.
My 401k will lose over the next two years? Possible, but I'm an optimist and look forward to better times ahead.
Regrets? I've had a few, but I'll get over it. Thanks for telling me what you think. I DO appreciate it!

[54regcab]

Keep in mind contractors tend to oversize to be "safe" in the event of a non perfect install. Larger equipment is cheaper than installing it correctly, fixing ductwork, and fixing the house. Energy bills are of little concern to the installing contractor, they just want to not get callbacks...

You have already see the result of fixing the house and at least partially correcting the system. Think what would happen if it was installed RIGHT and the house was fixed a bit more. 2.5 tons might even be enough if installed optimally and the house was fixed.

[beenthere]

You have a 20X20 return grille, if its a filter return grille, its good for about 1.5 tons of cooling at a velocity of around 380 to 400FPM. So since your return grille is under sized. Why trust that your duct work in the attic is anywhere close to being adequate. those that said its ok, may only be looking at its outer appearance, and not its size for air flow.

[Florida Joy]

Keep in mind contractors tend to oversize to be "safe" in the event of a non perfect install. Larger equipment is cheaper than installing it correctly, fixing ductwork, and fixing the house. Energy bills are of little concern to the installing contractor, they just want to not get callbacks...

You have already see the result of fixing the house and at least partially correcting the system. Think what would happen if it was installed RIGHT and the house was fixed a bit more. 2.5 tons might even be enough if installed optimally and the house was fixed.

Yep! I can understand how contractors might avoid callbacks by oversizing, but I don't get how larger equipment would be cheaper than installing it correctly. Cheaper to the contractor, maybe, but not to me. And if the ductwork needs to be changed, why wouldn't they tell me? I'd be paying for it, not them.

I like the XL20i, and have been considering the 4 ton, since it would run at 2 ton most of the time and only cycle up to 4 ton occasionally. In considering the 3 ton, I'm wondering if the 1.5 ton 1st stage would get me the desired comfort without having to run in 3 ton mode most of the time and costing me more in electric. After all, if it runs as a 3 ton most of the time, I'd be $ ahead by buying a 3 ton single compressor model, wouldn't I?

[Florida Joy]

You have a 20X20 return grille, if its a filter return grille, its good for about 1.5 tons of cooling at a velocity of around 380 to 400FPM. So since your return grille is under sized. Why trust that your duct work in the attic is anywhere close to being adequate. those that said its ok, may only be looking at its outer appearance, and not its size for air flow.

I agree with your thoughts about the ductwork, BUT.... who the h*** can I trust to evaluate its size for air flow? I've had the FPL energy survey done... I paid them for a duct test and they said it's OK, except for minor sealing required at the outlet boots and at the air return, which I took care of last week. They evaluated my insulation, which was low and I took care of that by blowing in R30 last week.

How does one get a proper air flow evaluation?

[vstech]

the only way to know if your ductwork is OK is to measure it's dimensions, lay out all the fittings on paper, and evaluate the layout for CFM, Distribution and air Speed. also, the ductwork needs to be in the correct position, and the proper registers for throw and distribution in the rooms. was a blower door test done on the ductwork for leakage? if not, then it's doubtful the ductwork is "OK"...

in the 80's it was rare to seal any fittings to the plenum, and rare to seal the take offs to the registers.
here's a test for you.
pull any register off the wall, and look into the duct. is there any sealant on the ductwork? if not your ductwork is inadequate for your house by today's standards of energy efficiency, unless ALL your ductwork is inside the house. nothing in the attic, nothing in the crawlspace.

[54regcab]

Yep! I can understand how contractors might avoid callbacks by oversizing, but I don't get how larger equipment would be cheaper than installing it correctly. Cheaper to the contractor, maybe, but not to me. And if the ductwork needs to be changed, why wouldn't they tell me? I'd be paying for it, not them.

I like the XL20i, and have been considering the 4 ton, since it would run at 2 ton most of the time and only cycle up to 4 ton occasionally. In considering the 3 ton, I'm wondering if the 1.5 ton 1st stage would get me the desired comfort without having to run in 3 ton mode most of the time and costing me more in electric. After all, if it runs as a 3 ton most of the time, I'd be $ ahead by buying a 3 ton single compressor model, wouldn't I?

There is a lot of labor involved with fixing ductwork. A contractor would rather just sell you a bigger unit rather than spending 1/2 a day fixing ductwork. Remember their main objective is that you are cool and they don't get callbacks, not your energy bills. Another thing to keep in mind the 3 ton would only kick in for the afternoons, during the night/mornings it would run @ 1.5 tons most of the time. Unless your utility costs are high or you want the 2 stage for comfort, it's hard to justify one based on energy savings alone. The 1.5 ton mode would help a lot with humidity during times of low demand.

If it were me I'd go 3 ton single stage and fix the ductwork. Also, if your current system is working properly I wouldn't replace it just for energy savings. Investigate fixing the ductwork with your current system and see if it's practical.

[beenthere]

You need to find a company that knows how to check ESP/TESP. And then know how to remediate your duct work for better performance.Not something easy to find I know.

[Florida Joy]

the only way to know if your ductwork is OK is to measure it's dimensions, lay out all the fittings on paper, and evaluate the layout for CFM, Distribution and air Speed. also, the ductwork needs to be in the correct position, and the proper registers for throw and distribution in the rooms. was a blower door test done on the ductwork for leakage? if not, then it's doubtful the ductwork is "OK"...

in the 80's it was rare to seal any fittings to the plenum, and rare to seal the take offs to the registers.
here's a test for you.
pull any register off the wall, and look into the duct. is there any sealant on the ductwork? if not your ductwork is inadequate for your house by today's standards of energy efficiency, unless ALL your ductwork is inside the house. nothing in the attic, nothing in the crawlspace.

The contractors (the two I'm considering) have been in my attic. The others didn't go up there and weren't invited back after they tried to "sell" me anyway. The two contractors have seen the sizing and layout of the ducts and verified the positioning of the registers. The FPL energy survey included a blower door test. Ducts had already been sealed at the plenum (current A/C is not original 80s equipment and neither is the ductwork). The only leaks detected were where the ducts meet the boots at the registers. There is sealant in the ductwork at the registers now because I stood there and watched while those repairs were made last week.

What else can I do to be sure my ductwork is adequate?