Results 27 to 39 of 211
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08-12-2012, 12:41 PM #27
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08-12-2012, 01:13 PM #28
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.
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 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.
Which makes more sense to you?
CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.
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08-12-2012, 01:13 PM #29
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.
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08-12-2012, 01:19 PM #30
Because your neighbors are doing it, it must be correct? I hope you didn't think about that before posting.
Which makes more sense to you?
CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.
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08-12-2012, 01:31 PM #31
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.
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08-12-2012, 01:56 PM #32
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.
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.
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!
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08-12-2012, 02:02 PM #33
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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.
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08-12-2012, 02:13 PM #34
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.
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08-12-2012, 02:24 PM #35
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?
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08-12-2012, 02:30 PM #36
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?
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08-12-2012, 02:32 PM #37
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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 TRUE highest cost system is the system not installed properly...
The three big summer hearththrobs...
Mel Gibson
Dwane Johnson
The A/C repairman
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08-12-2012, 02:41 PM #38
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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.
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08-12-2012, 02:42 PM #39
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.



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