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Discussion Starter · #1 ·
If I had 10 contractors come out, I'm sure I'd get 10 different recommendations! So far it's 3 and 3 so I'm trying to understand what will be best for our house then have the one contractor that I feel the most comfortable with do the work.

We have a 2500 sq ft. house that's about 13 years old. We're in North Texas so we get hot, and we can get cold. Current unit has 1 14" return and 1 12" return both pulling through multiple registers in the wall. Condensing unit was replace 5 years ago and is a Heil (we were in a pinch)

I'm looking at Trane. I know we want the XV80 variable speed furnace. If we replace the condensing unit as well, I'm torn between going ultra high efficiancy although I know we won't get the savings to offset cost. Our cooling cost isn't that bad now but I like the "other" gadgets like dual compresor, quieter operation etc.

I have a few questions:
1. with a 5 ton unit, I understand we can go with a XR 12 (12 SEER) and get an effective 13 SEER. If we go with a XL14i we'll still only get 13 SEER. A XL19i should only yeild 16 SEER, although one contractor told me it was a true 19 SEER and that the tonnage didn't affect efficiency. He also said 410 was more efficiant than R22, but I've seen where same units are 1 SEER less when running 410 vs. R22. If our cooling cost is already pretty good, does it make sense to go with anything over the XR12? Unless we just want the fancy "stuff" and cool look of the XLi series?

2. W/O seeing the house, does that return seem sufficient? ONe says more than enough, one says new units need much more etc. etc.

3. Do the newer compressors require 1 1/8" suction line or is the old 7/8" good enough? Again, one says one thing, the other say another.

4. Coil??? I haven't figured that out yet. It sounds like there are 2 different coils that could be used. A standard 5 ton coil and a coil that has some other features that "may" be required with some function rich condensing units. If we keep the current Heil until it dies, should we plan ahead and ask for a specific coil over and above a "standard" coil?

5. Filtration. Ug. One good 5" filter on the furnace, or filter all return registers? UV Light or not? Electric filters sound like that have a lot of maintenance and may not be worth the $$$.

Whew, so there you have it. I could talk on and on about it, and I'll probably know more than I ever cared to about HVAC once I'm done. I'm just frustrated that I'm getting so many different opinions. In one case, I think the guy was a salesman and not much on HVAC. He just said some things that were a clear sign of not being "fully" aware. Things I've learned along the way.

I have a short list and I know who I htink I want to do the work. He's also higher $$$ and I'm not sure that maybe on a couple of things he could be a little overkill on, like return air.

Any help would be greatly appreciated

227 Posts
You have quite a list there. I'll see if maybe I can help with a few of those items for you.

1. Make sure a load calculation is done on the home and the units properly sized. Todays higher efficiency a/c units do not necessarily run the same amount of time as "your old unit" does. Also, actual BTU ratings of the unit may differ. An older 5 ton could have been an actual capacity of 56,000 BTU and a newer 5 ton actual capacity is 59,000 BTU. True SEER will vary on tonnage and type of unit. You can verify true SEER ratings at and see what size a/c match with which model of coil matched with which type of furnace gives the best efficiency. Yes, R410 by it's nature is a higher efficiency unit at its baseline but you are also correct that at varying sizes and match ups, it can be +/- an R-22 system as well. I would only consider a higher efficiency unit (a/c) if you plan on being in your home long term (over 10 yrs.). Otherwise, the payback just isn't there. Now in 2006, the DOE has mandated that residential split systems manufactured cannot be anything less that 13 SEER (ARI rating) where the current is 10 SEER. Although it does not affect you and your current purchase, I mentioned it as I have seen some salesmen and companies use that as a scare tactic into spending more money when they really didn't need to.

2. You cannot have "too much" return. The more places you pull air from, the less places you have that will get cold/clammy in the summer and miserably hot in the winter. Without looking and knowing what the proper size unit should be for the home, know way of knowing if the supply and return are sized adequately. Yeah, we have all heard of the "Rules of thumb" but guessing just don't cut it in todays world of HVAC equipment.

3.Depends on the brand and size of equipment although if you do in fact need a 5 ton Trane unit, they are sized with a 1 1/8" suction line. Will it work with 7/8"? Sure but you loose efficiency as again they are designed and rated with that size for a reason.

4. Trane has a couple of models of coils and if you truely want high efficiency, you need the one with a TXV installed. A TXV metering device adjusts to the load where as a fixed orfice or "flowrater" type just meters in one amount of refrigerant regardless of conditions.

5.To avoid excessive static drop, a good 5" media filter such as an Aprilaire of Trion Airbear are better than putting 1" media filters in every retun. 1" media filters do great but they load up quicker and increase the static pressure (slow the air down) easily. You could spend more in 1 yr. keeping 1" pleated filters changed each month than buying 1 even 2 (if needed) good 5" filters a year. Now the Aprilaire 5000 filter is one of the best Electronic combination air cleaners I have seen. A plain EAC is high maintenance as they do need the cells washed out once a month to keep them effective and keep the amp draw down on the plates. UV lights if installed properly are very effective and again, they have made them easier and cheaper to service. Most bulbs will last up to 2 years and require little more than a dusting off every 6 months to keep the light(s) at their "brightest". With a variable speed blower and the likelyhood that you will have it run all the time, you will be constantly killing bacteria, mold and viruses in the air. Keep in mind though it does not mean that you will never get sick LOL as sometimes people think of them as a "magic pill".

Post anymore questions you might have as I am sure others may have some ideas or options/experiances as well. Good luck!

Discussion Starter · #3 ·
Thanks for your reply, that was very helpful. It helps support my gut feel with at least one of the "Salesman". The one that is still on the top of my list was an installer and really seems to know his stuff, and is more consistant in his information.

I'm leaning towards just having the Furnace and coil done right now. Although we won't get the effeciancy out of the older condensing unit no matter how we match it, it still has a few years left in it and I can't see saving more than a couple hundred dollars a year in cooling at the very most.

Right now the currnt coil is doing OK. It's draining as it should and not longer draining out the bottom into my "bucket". So I assume the drain pan has finally dried out some. We're also geting into the cooler time of year so it's going to start working less and less. I'm sure the crew that does it would also much rather do it when it's in the 70's-80's in the attic rather than 100+. LOL

Thanks again.

Anyone else with any other comments, chime right in......
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