10, 12 or 14 SEER? Help!!!!
I am currently building our new house here in Marietta GA, just north of Atlanta and I need to make some decisions fairly quickly w/ regards to the efficiency of the A/C and furnace units we’ll be getting.
Atlanta is typically hot and muggy (!) from mid May to September and ocassionally into October. Moisture/humidity is a real factor as well on our property where we have a lake and creek close by. The lot is also heavily wooded which tends to trap a lot of moisture in the air creating something of a micro climate around the house. In fact, we opted for vinyl windows over wood for that very reason.
My installer has given me prices for a basic 10 SEER system w/ an equivalent furnace along w/ prices to upgrade to 12 and 14 SEER A/C and 80% & 90% var. speed furnaces. The price differences aren’t outrageous and are probably doable budgetwise. My concern is, is it really worth it? I’d hate to waste money on something if there will be no appreciable return in energy savings. We plan on being in the house at least 10 years and probably more. The house will be well insulated and wrapped w/ Tyvek so it should be reasonably energy efficient already.
Any thoughts on the matter would be greatly appreciated!!! Thanks!!!
Replies
10 seer are builders models with possibly non scroll compressors and no hi or low pressure switches
buy 12,
avoid 14 (complicated hi priced parts)
The higher the SEER, the more efficient and also the quieter it will run. I'm in the northeast and would go with the 12, the small price increase over a 10 is not worth it. Where you are in the South, I would go with at least a 13 and higher if the price didn't get ridiculous. Also, check this link.
http://home.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view&newsId=20050616005637&newsLang=en
Got this pic from one of the AC websites (can't remember which). It gives a very practical application of the different SEER's.
View Image
As far as the muggy climate, that is more an issue of proper sizing on the unit. If the unit is too large, it won't run long enough to get the humidity out of the house. If the unit is too small, it won't keep up. As long as your HVAC person has it sized correctly (based on the size of the house, the insulation values, etc), you should have a comfortable house no matter what the SEER of the unit.
My 2 cents would be to get the highest SEER you can afford, but to also inquire into the warrenties on the units.
jt8
A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty. -- Sir Winston Churchill
Edited 6/20/2005 12:40 pm ET by JohnT8
Thanks for all the input so far! I forgot to mention in my original post that if I go up to the 14 SEER, I get a 10-year parts & labor warranty which is not available on the 10 or 12. So I really need to factor that in as well. I have to assume that the units would be relatively trouble free for the first few years but I imagine the warrranty could really come in handy several years down the road. Seems like a compressor replacement at around year 8 or so would not be out of the question. Also, this is a 3 A/C unit house so if they start having issues, I could conceivably spend the amount for the upgrades in repair costs later... and still be paying higher monthly utility bills.
At this point, I'm really leaning towards the 14 w/ the 80% var. speed furnace. But please, keep the thougts coming in!!
You might want to check both your electric and gas utility rates before making a decision.I am looking at replacing my systems and it appears that the electric rates are low enough and I run mine such a short time (8-10 weeks) that a higher SEER will not save that much.But the winter rates are real low and I am looking at heat pump with resistive backup instead of gas.You might want to look a dual fuel system; heat pump with gas backup.I don't have any number but spending some of the difference on better insulation sealing will give better return than the best eff equipment.Also there are other difference in equipment than just efficiency. But one company might have several different series so getting a higher seer in the lowest series might not be as good a quality as a better line in a lower seer unit.One of the feature is the variable speed, which is a very good option. And check to see if it can be setup with the AC to start each cycle on slower speed for increased dehumidification.Other quality features include things like extra compressor safety cutouts, better cases, etc.
Some of the high seer units have very complicated and very very expensive fan motors and control sysytems. If those fail you lose a lot of "savings" when you pay $600 to replace a complicated motor-
Which is why a good warrenty is important. Sounds like the original poster has a good warrenty with the one he/she is looking at.jt8
A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty. -- Sir Winston Churchill
I'd recommend the 14SEER units.
I put two of them in my own house, no problems for the past three years. Run much quieter than the neighbors' units.
In Atlanta the furnace doesn't matter much, but for an AC you definitely want at least the 12 and probably the 14. Your utility company will probably give you a rebate for the 14, plus you'll be saving at least $500 a year, I'd guess.
Reliability-wise, so long as it's a decent brand with a decent warranty, and installed by a reputable outfit, there's no substantial difference. (Yes, Fred will tell you that his 14 SEER blew up in 6 months, and Joe will say that his 10 has been running for 15 years, but when you look at the overall statistics there won't be much difference.)
tejan,
I would think that in your location the highest efficiency AC would be desirable. I would like to mention one thing about the furnace. If it is gas and you are used to the older quiet burning gas units, you might want to go listen to a high efficiency one before you purchase. Our new high efficiency gas unit is actually noisier than the 25 year old oil burner it replaced. The power flue fan has an annoying noise. In our particular house, the furnace is in a closet adjacent to the rec room so it is annoying to have to turn up the TV every time the furnace starts burning. If yours is in a basement and you cant really hear it, then it should be ok.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
Did your A/C guy tell you that the 10 seer is obsolete and new codes will require a higher seer? Don't let them unload the 10 on you just to clear their inventory.
No they are not obsolete.The minimum allowed AC is still 10 seer. Those manufactured after Jan 23, 2006 have to be a minimum of 13 SEER.
That's what I meant. And 10 is/will be obsolete.
And so will the 12.But there is no need for them to try and clear out stock.It only affects manufacture of new units.
Edited 6/21/2005 1:00 am ET by Bill Hartmann
Tej: Sounds like you have talked to Reliable Heating & Air - the outfit that Neal Boortz pushes. I bought a Carrier dual fuel heat pump at 13 SEER w/ a high efficiency furnace & a variable speed AC about 3 yrs ago. They gave me a 10 yr warranty on it, & their service has been great at getting me up, runnning & happy, even though it is nearly a 40 mile drive from their shop. We are happier than pigs in slop w/ the system. Someone already said it - invest in some extra insulation - you don't want to put a Roll Royce HVAC in a Yugo. W/ active computer controlled zone air handling, we dropped about 11Grand on the system; but we really like it.
Don
In your area a 90+ variable speed, 2-stage furnace is probably a big waste.
I would recommend, first that your perform heat gain and loss calculations on your home (or have the contractor(s) show you the ones they performed). Where you live cooling and dehumidification are a much more significant source of energy usage than heating.
I would recommend, once the proper sizing calculations have been performed that you get a basic furnace (go w/90+ only if venting with PVC is a necessity) 80%, 2-stage and athe 14 or 15 SEER AC. Those who would tell that these units are "too complicated" are idoits and probably refuse to have fuel injection on their trucks. The higher efficiency units are typically top of the line and come with excellent warranties. For instance, Goodman, about the least expensive option in the market, 10 year on all parts and Lifetime on the compressor. That's pretty good to "take a chance" on.
cost versus payback versus comfort
variable speed furnaces will be more comfortable and cheaper to run - especially important if you want to put in a good media filter and run the blower on low all the time. The variable speed blowers are great for that.
The payback on a 90% furnace for your area is WAY too long.
I recommend the 14 SEER A/C units
We bought a high efficiency furnace, knowing that it would probably never pay for itself. BUT - We live a long way out in the sticks & have to buy propane. We also installed a 500 gal tank so we can stock up when the price is "Cheap." One tankful lasted us two yrs. Kinda nice not having to think about getting a refill in the dead of winter when propane costs as much as gold bullion. We think of it in August when the price is low. Please don't give me the line about the current cost of money, etc. I'm busy enough w/o having to think of the relatively small margins on propane & how much more we could make by investing the difference. Don't need that stress. Also BOUGHT our own tank & shop for propane when the time comes. Out furnace comes on at night starting in late Nov & goes dormant in late Mar/early Apr.DonThe GlassMasterworks - If it scratches, I etch it!
Just bought a 10-SEER unit in KY. Also hot, humid summers, but we have the bad winters to match (nothing like up north obviously, but sometimes gets below 0). Anyway, based on last year's summer electric bills we figured to save about $100/yr by upgrading to 12-SEER, which was about $600 more expensive. Not knowing how long we'll be there, AND CONSIDERING THE TIME VALUE OF MONEY (which the salesmen never talk about), we opted for the cheaper unit. Also we had to have duct installed, so the price tag was already pretty high.
R.e. the furnace, we were originally going to go with a heat pump. However, the extra expense (b/c we were still going to get a furnace for backup heat) and the "not-so-hot" air that it produces in cold weather caused us to change our mind. We then looked at an 80% (currently have a boiler & radiators - very old house) gas unit, but then found out I'd have to have a flue stack going up the side of the house. Considered going to the 90-92% unit so we could use PVC flue, but the price was about $1,000 higher. Decided to go back to my original plan of installing a coil and running a line from my boiler to it.
As several people have mentioned, by far the best bang for the buck is good insulation. If the heat can't get in (or out in the winter), you really don't need much of a unit at all.
Lew, you bring up a good point, the time value of money. In response to a similar question, I put together this little XLS calculator that allows you to compare the relative efficiencies/paybacks based on SEER levels. It is entirely possible that I got something wrong, but my analysis even for NE shows some pretty large paybacks due to the very high cost of electricity up here. As I expect to spend a long time in my home, I went for a 20+ SEER Lennox unit (the XC21), not only for the energy savings but also to keep my neighbors happy (noise).The attachment is pretty self-explanatory. Just enter your local conditions to the left and let the Net-present-value (NPV) calculator do the rest. If the NPV of a higher efficiency level unit is higher than the marginal cost of buying it, then the higher efficiency unit should be chosen.
Edited 6/29/2005 5:30 pm ET by Constantin
Argh. I tried to fix the attachment and it only lets me delete it... so here is the improved file.
Nice tool. Pretty hefty electricity rise though - 5% over CPI?
We do have cheap electricity here - less than $0.06/kwh. Probably should have mentioned that before. Our electric rate has not increased anywhere near 5%, much less CPI + 5%. I started keeping track of utility bills in Jan 02, and the rate has been pretty flat since then.
I might change the captions somewhat, like the risk-free cost of capital. It's really whatever average rate you're A) paying creditors or B) making on investments, assuming that is where the money would otherwise go. Also, life span of equipment should probably be "expected time you'll spend at this house" or something like that.
I did not see any glaring errors in your financial methodology though. Is that how the SEER raing is calculated? I'm not familiar with cooling-degree days. Does that somehow account for the variance in temperatures? In other words, does it assume that you're always at the design temperature for the whole season?
Lew,The reason I labeled it risk-free capital is because that's the measure I was taught to use in business school. Whenever you start paying creditors and the like, you also have to account for the risk premium that creditors slap on top of the risk free rate (i.e. treasuries) since the assumption goes that the government will be more likely to pay its creditors than you are.Th reason the risk free rate is appropriate is that there is no risk that you will not make the savings. Furthermore, as savings are not taxed, you can also eliminate the whole issue of tax treatments and the like.As far as the lifespan of the equipment is concerned, it's the life of the equipment or your expected stay, whichever is shorter, when you're being conservative. One would like to think that higher-SEER equipment would command a price premium on home resale, but anecdotal experience shows this is mostly no the case.I am happy for you that your utility bills are flat. Up here in the Northeast and out in CA, a lot of energy is produced with gas-fired turbines, i.e. the kinds of fuel plants that are very sensitive to the vagaries of the energy markets (coal is much more stable). Since NIMBY concerns will continue to keep coal, oil, and nuclear fuels out of the Northeast, I expect that the balance of our growing energy needs will be in the form of gas-turbines, further pushing up demand and pricing. What's even more entertaining about the whole situation is how heavily the gas utility is trying to get oil customers to switch to gas and that of the $1.40 a therm we pay up here, $1.05 is just for transportation.Anyway, as for SEER and how it works, there are many great online resources, none of which I can point you to on the top of my head (and it's bedtime). Have a google if you want an exact answer. My short answer is that the SEER rating is a bit of a mythical beast, i.e. a measure of how many watts it takes over an entire season to remove so and so many BTU's from your home. The SEER rating assumes a normalized "season" that may or may not exist where you live. I imagine that it's probably population/AC incidence-adjusted for somewhere near DC. Hence, SEER does account for temperature fluctuations and is a measured standard, just like the more straightforward EER. However, since SEER is predominantly measured under less stressful conditions than EER, the power companies prefer using EER measures instead of SEER because it reduces the spikyness of summer demand patterns (which usually occur under stressful conditions).Cooling degree days (CDD) are a measure you can lookup at wunderground.com, NOAA, and other online resources for your locality. It's basically a measure of how many degrees hotter than 65*F a locality is in a given year. So, a 75*F average day would turn into a 10-degree cooling day, for example. Our area allegedly has 777 CDD, 5650 HDD, and utility rates have been racing ahead of all other CPI measures.
If its reasonable I'd get the 14 seer with a 10 year warrenty. Seems like a decent amount of time to not worry. I bought 13 seer with variable speed fan last summer and am happy with it.... the way the fan ramps up and down is a lot more pleasant and is supposed to be more efficiant. Also, make sure you have decent insulation in the attic... a new house should have at least R30 I would think. My split level built in '69 only has about R10, I'm paying about $600 to have it "upgraded" to R30.
kevin