View Poll Results: Which contractor is most right?
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Contractor #1 is most correct.
Contractor #2 is most correct.
Contractor #3 is most correct.
All 3 contractors don't have really have it right.
Variable speed w/older furnace? Can a new R22 coil/lineset convert to R410 w/a valve?
I just had three contractors bid on putting in central AC. All three contractors came up with very different bids with different sizes and details, and I am asking your help figuring them out as I am pretty confused.
Background info: my house is a 1200 sq ft, one story, 1962 brick ranch near Denver, CO. There is also a full finished basement. The 125,000 BTU Janitrol forced-air gas furnace is newer, replaced in 1993. There is already a large, Goodman U-49 coil sized for up to a 4-ton condenser (or so I'm told) installed above the furnace (coil is an R22), but no refrigerant lines (20 foot run to side of house). I can't tell what year the coil is from but seems likely that it would have been installed in 1993 with the furnace--before I owned the home. The forced air ducts that are in the basement ceiling are metal ducts and the tin-over-joist space method to carry return air. There is no insulation at all in the exterior walls, which I will probably try to have corrected asap with blown-in insulation, and there is 6" of cellulose fill in the attic. The windows are brand new (2006), low-e, double-pane vinyl windows.
Now to the bids:
#1) Will install a 14 SEER 2.5 ton Goodman model 140301 with a 2 year labor warranty, using existing coil.
#2) Will install a 13 SEER 3-ton (he recommends going a bit large due to the age of my home, though he would be willing to install a 2.5 ton 130301A also) Goodman model 130361, again using my existing coil. His labor warranty is only one year. Also, he says my furnace blower won't fully utilize a 14 SEER Goodman model--something about the blower not being variable speed?--and I'll just get 13 performance anyway because I will run it like the single speed 13 SEER unit.
#3) Wants to rip out the existing coil and install a 2-ton R410a Lennox Elite XC13 (13 SEER) for much, MUCH more money than #1 or #2, whose bids are almost exactly equal. He has a five year labor warranty but only if we either sign a yearly maintenance agreement with him or maintain it well ourselves.
All three say they did manual J worksheets on the house and then compensated for their experience in the area. All three have excellent references. #2 lives in a house of similar vintage and construction to mine. I've been working with #2 the most so far, but mostly because the electrician he recommended impressed me the most. (The electrical bids were done separately as I needed a service box/panel upgrade to pass code.)
My First Question: The 14 SEER unit from #1 is somewhat attractive to me, but not if #2 is right that I would really need to upgrade my furnace blower (and thermostat?) to make it work. Who's right?
My Second Question: I am also getting conflicting information about whether I can convert the existing coil and new lineset for R22 to R410a if I should need to replace the AC after 10-15 years. #2 claims that he could just put in TXV valves (I didn't quite catch the exact part?) to keep the existing coil in use and his lineset installation would be able to take the higher pressure of the 410a (after it is flushed). #1 says his lineset will be ok for reuse but the coil will need to be changed out. #3 says everything would need to be ripped out as all line and coil sizes are matched to the refrigerant. Everyone agrees that I would need a new condenser/compressor unit to change refrigerants.
Who's right? Is #2 full of it? Is #3 overselling me?
One more note: #1 and #2 both say they have no philosophical reason for recommending a R22 system, just that they can put my existing coil to use. They'll each do a R410a system, but it would be more--closer to, but still significantly below, the bid of #3. #2 said he could do it a little cheaper by making the existing coil work with a new 410a system if I wanted to go that route. They both say that with a good installation like theirs, I shouldn't have coolant leaks so the expected price rise for the phaseout of R22 will likely not affect me until enough years pass (15+) that I am likely to be considering replacing the AC condenser anyway. (Actually even #3 also said that I would be unlikely to be affected for 10-15 years if I had him put in an R22 unit right now.)
Thanks so much for your help. I tried to be as detailed as possible, sorry for the length.
Didn't see anything useful there
Thanks, but that website told me nothing about the technical issues I raised about whether a lineset/coil installed for R22 could be used for R410 by this "adapter valve" my second contractor talked about. If I missed something, let me know.
Originally Posted by dash
sorry about that,thought it might be of interest to you,as Puron/R410a is the future.
Line set can be reused If it's the correct size,if it's easy to replace then replace it.
The coil may or may not be acceptable,post the brand and model number to find out.
The coil brand is Goodman, model U-49, the part number is 15342-44. It also says "design pressure 90 psig, factory test pressure 150 psig."
The serial number on the coil begins with 99 and the furnace serial number begins with 97, so maybe I have the years of installation wrong if the manufacturer encodes the date it was made into the serial number.
Thanks for replying!
Originally Posted by dash
Unfortunately, I don't have the resources to get critical information from the part numbers and such that you have provided, so I didn't vote.
However, I can tell you that 410a is NOT a retrofit. In other words, any refrigerant will work satisfactorily in a 410a system, but 410a will NOT work safely in a system for a lower pressure refrigerant. Contrary to what one of your contractors told you, the system does not technically have to be sized according to each refrigerant. Most common line sizes are appropriate for most common refrigerants. In the case of 410a, this is a higher pressure refrigerant than this industry is accustomed to using. Thus line and coil sizing is a little different. They both must be sized specifically for 410a.
My suggestion: For the area you live in, a heat pump is a relatively energy efficient alternative. I realize it gets very cold near Denver. Unless you are in the mountainous regions near Denver, cool period heating can be accomplished more efficiently via a heat pump, placing your gas furnace in the role of secondary heating source that will kick in when the heat pump can't keep up. This is especially applicable if you truly intend to better insulate your home as your heat losses will be severely diminished.
Although 13 SEER is quite good, there are much more efficient systems available. I'm talking 21 SEER and upwards from there. If you plan on staying there for any period of time, a higher SEER rating in a heat pump system would significantly increase your yearly energy savings. And even if you don't plan on sticking around, adding a high efficiency heat pump system will greatly increase the value of your home.
Emerson Climate Technologies
01 out of 10 people don't understand binary.
"Size matters not."
-Yoda, Jedi Master
Coil question still remains
I'd still like to know more about whether that Goodman U-49 coil is too big for a 2.5 ton a.c, and whether it would have to be replaced to convert to R410a, but it is accessible compared to the lineset. (More details on the coil in an earlier post.)
But I'm finally getting closer to part what I'm really looking for, which is whether I could reuse the lineset work to be installed in the finished basement ceiling if I ever have to upgrade refrigerants while I still live in the house, should I still be living there 10-15 years down the road. The answer appears to be "Maybe" because the lines will need to have been sized and brazed to withstand the pressures of the new 410a installation, and the exact sizing depends on knowing what 410a system is being installed at the time it is installed.
Thanks for the suggestion about heat pumps, but I'm not looking to upgrade furnace efficiency at this time. I've done the math, my budget is limited, and the payback on adding a heat pump is too slow compared to other expenses like adding insulation that I am going to undertake first. Unfortunately, since we both have offices in the house, getting central AC installed before the summer has become a priority. If it wasn't for my allergies, I might have gone with a swamp cooler in CO's very dry climate from a purely energy efficiency standpoint anyway.
Originally Posted by StealthSuitStan
i would run away from anyone willing to put a 410 unit on a 14 yr old coil...
I can see why you are confused, as I am now confused and I am supposed to be the pro.
The way I would do it, is run the manual J and show you a copy. That is the proper size. I would then want to start from scratch, new coil, lines, electrical, and outdoor unit. So I could warranty the entire install. I would give you NO warranty if I have to hook up to a 14 year old coil. Scratch that - I would not even think about hooking up to the existing coil. Then you would have the choice of refrigerants and efficiencies. If you want 14 seer I would use a combo that gets 14 seer, same thing with the R410A if that's what you want then that's what you would get. Make them show you the Manual J and then go from there. Hope that helps and doesn't confuse you more than you already are.
We only want to do it, if we can do it right.
If you have a coil that has never been used, again NEVER been used you should be ok to use any refrigerant you choose. Same rules apply to the lineset, as long as the lineset is not pre-charged with R22.
Efficiency will be adversely affected by using an older coil and personally I would pull the coil, try to sell the old coil on craigslist or E-bay, and go new thru out.
If the coil has been used, as in ever hooked up with refrigerant ran thru it, you only have R22 as a refrigerant option. The reason for this is that the oil used with R22 is not compatible with R410a. Again, same with the lineset. It doesn't sould like a big deal but it is!
As an industry note, all A/C systems are CLOSED loop systems. Any good company will fully evac any install or service (where this loop is opened) down to a stable <500micron vacuum. This proves the system sealed and de-hydrated. My apologies to your contractors but this is a requirement not a sales factor!
Here in Denver it is recommended that we use TXV's for any install rated over SEER 13. Also @ our altitude it's advisable to upsize the indoor coil by 1/2 to 1 ton of cooling. Excel actually requires both of these for any of their rebate programs.
Personally I install R22 almost exclusively, mainly due to the cost difference with marginal if any benefits to R410a.
From my experience I'd say they're all wrong, but #3 is the closest to being right.
Hope it helps,
To replace just the outside condensing unit is a quick and easy job, it is also the
wrong way to do the job. This is why these two dodo's are cheaper.
The Lennox guy is doing you a bigger favor than you could ever know.
Is the Lennox guy going to be more expensive when you compare his job cost to replacing your Goodman condenser again in 3 years? Replacing the indoor coil is very labor intensive, it requires some more skills than just slapping in a condenser.
I hope they already solved this problem by now. 05-03-2007 05:49 PM