SEER numbers and where do you draw the line?


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Old 07-30-10, 05:22 PM
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SEER numbers and where do you draw the line?

We are planning on replacing our mechanicals, to get the consumption down to modernish levels. House is about 15 yrs old. AC was added about 10 yrs ago, maybe less.

Furnace is a Carrier and was the "standard" efficiency in the day but I forget the percentage, and is natural gas.

AC is Amana 2 tons and I found a label on it showing the seer rating is 10.20.

We are also upgrading to a tankless water heater.

Brother in law is in the business and can do the parts at his price.

He has in mind an Amana heater which is 70K btu, 95% efficient, and variable speed fan.

He is suggesting an Amana AC (not sure if ihe is quoting just for the condensor or the A coil as well), but it's a 13 seer rating. A step up I know, but why not higher? He says cost multiply quite a bit when going above 13 seer. Again, maybe the 13 seer he can reuse the A coil, so that's an additional expense, or just the condensor is that much more?
He also says the condensors get quite huge on the higher seer numbers, which a quick check, apples to apples on 2 Amana units shows that just going from a 13 seer to a 14 seer is 5" higher already.
He also doubts that the excess expense for the higher seer units will even be regained through the life of the unit.
So, any opinions appreciated, just sort of double-checking what he is saying.

Also any pros or cons on going tankless. It's just my wife and myself, so not a lot of hot water use.
Gilly
 
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Old 07-30-10, 11:04 PM
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Tankless is the way to go will save you lots of lp. If he is in the business why not go with a good unit like a trane etc. The lower end equipment is cheaper for a reason, power is not getting cheaper I would not go with at least a 15 seer. You will see a payback in any unit! A 19 seer maybe not in energy but you are buying comfort at that high a seer.
 
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Old 07-31-10, 11:56 AM
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Arrow They should have left it at least at 12-seer

Well, they're talking about raising the minimum SEER to 16; hope NOT!
They should have left it at least at 12-seer.

The only reason I would go to a 14-seer is to make sure I got a Copeland Scroll compressor & a TXV metering device on the cooling coil.

Proper sizing of the equipment, ductwork & airflow have the biggest effect on the actual Delivered SEER Rating!
 

Last edited by HVAC RETIRED; 07-31-10 at 11:58 AM. Reason: typo...
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Old 07-31-10, 01:05 PM
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Estimate the number of hours per year your A/C runs. Then, for different SEER ratings, you can calculate the electrical energy used per year for A/C, and multiply by your electrical cost, $/kWh. If the extra cost for the higher SEER unit doesn't give a payback within 3-5 years, then I would forget it.
 
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Old 07-31-10, 01:57 PM
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Originally Posted by Mike Speed 30
Estimate the number of hours per year your A/C runs. Then, for different SEER ratings, you can calculate the electrical energy used per year for A/C, and multiply by your electrical cost, $/kWh. If the extra cost for the higher SEER unit doesn't give a payback within 3-5 years, then I would forget it.
Good post Mike.

IMO, putting some investment in reducing air infiltration & other things to reduce both the heating & cooling yields a better payback than going to very high SEER systems.

Also, Reducing cooling tonnage makes the duct system more efficient.
 
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Old 07-31-10, 03:25 PM
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15 seer should be the lowest seer to go with. 14 seer is way to low you will be paying big bucks to the man.
 
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Old 07-31-10, 05:03 PM
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I'm in Wisconsin and the AC only gets used during especially hot periods (over 80 or so) and even then usually just in the evening, if that makes a difference. I assume that would be significant info. No one is home during the day so we can't see running it constantly
The furnace on the other hand we are going to get a 95% efficiency.
The AC will be 2 ton.
 
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Old 07-31-10, 05:12 PM
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Best to compute the payback for a higher SEER, as posted below. Otherwise, based on what you say, I would tend toward a lower and cheaper SEER.
 
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Old 07-31-10, 05:36 PM
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That's sort of what the bother in law indicated too. He is recommending a lower seer AC for this area, and given how we use the system. Our current unit is a 10.2 seer. My wife was all for energy star and a 16 seer, but brother in law said no way would we benefit by this. He said we really need to upgrade the furnace, which I believe is a 70% eff. rating, but just to go up to a 13 seer. He also explained why we need to stick with the 2 ton ac unit, something like the ac unit would not run enough to dehumidify properly? Although we use a small portable dehumidifier as the ac isn't run all day.
Another factor he sited was that our utilities are in the lower level of a trilevel home and doesn't have a very high ceiling. Not really "low" like a crawl space, but not as high as a normal full basement, and he is saying there may not even be room for the A coil over our furnace. (if we went to a 16 seer for example)

Also, since I'm asking, what could we do to get a bit better filtration? Right now, with the original system, the installers did what I consider to be kind of a hack job in getting a 4" wide filter between the return and furnace "intake" if that's the right word for it.
Just wondering what my brother in law might be able to do to get it so it's not so hacked looking, the filter doesn't even slide in to the space all the way. I can post a pic.
Gilly
 
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Old 07-31-10, 05:46 PM
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Originally Posted by GillyWI
what could we do to get a bit better filtration? Right now, with the original system, the installers did what I consider to be kind of a hack job in getting a 4" wide filter between the return and furnace "intake" if that's the right word for it.
4" wide? Is that a pleated paper filter or a fiberglass? Are you getting plenty of air flow?

What is the problem you see with your current filter? Lack of flow? In most cases, a fiberglass filter, less that 4", is fine. You can wash the evaporator coils every couple of years. Do you have an allergy problem?
 

Last edited by Mike Speed 30; 07-31-10 at 06:17 PM.
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Old 07-31-10, 06:14 PM
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Arrow Goldstar...

Originally Posted by airman.1994
15 seer should be the lowest seer to go with. 14 seer is way to low you will be paying big bucks to the man.
Well, the Goldstar legislation requires A/C equipment to have a minimum of 16-SEER/13-EER, & 15-SEER/12.5-EER/8.5-HSPF on heat pumps.

That is if you will ever be able to find anyone certified to do the Goldstar work
 
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Old 07-31-10, 06:30 PM
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On the filter, it's one of those pleated filters, the ones in the big cardboard box.
When they installed the furnace 15 yrs ago, they sort of cobbled this area between the return and the side of the furnace (inside the furnace in this same area there is a spot where you can install a thin fiberglas (I guess it is) filter.
Anyways, the pleated filter slides in this hand-made "gap", and the problem I have with it, is that the filter doesn't completely go in to this gap, and just by looking at it, air can also be sucked in which isn't filtered because it isn't sliding in all the way. If that makes sense. To try to explain it differently, the air can be sucked in on the furnace side of the filter as the filter isn't fully inserted in to this gap. Whole thing looks pretty crude to me.
Although, since you brought it up, no we don't have allergies or any other reason to think the air isn't being filtered. We're probably just being picky, but was hoping that we could get it so it "looks" right.
Gilly
 
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Old 08-01-10, 06:55 AM
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Arrow Tests in CA & found that SEER level differences were unpredictable

Originally Posted by airman.1994
15 seer should be the lowest seer to go with. 14 seer is way to low you will be paying big bucks to the man.
With all due respect, IMHO, SEER has been proven not to be a predictable indicator of actual deliverable SEER performance.

The difference between a 14-seer & a 15 or 16-seer can be easily canceled out due to numerous other factors.

If U use a differential room t-stat, IMO, the increased run-time-cycles will make more of a difference in SEER than between 14 & 16-seer ratings.

They ran tests in CA & found that SEER level differences were unpredictable...
 
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Old 08-01-10, 07:53 PM
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Yes many factors! But I would much rather have a 15 over a 14 any day! I will be buying a 19i when my 12 seer kicks it. Why because of the cost savings, comfort and I haven't seen power bills go down. Mine have gone up 75% in 5 years in no way is anything under a 15 seer a good buy.
 
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Old 08-02-10, 01:46 PM
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Originally Posted by airman.1994
Yes many factors! But I would much rather have a 15 over a 14 any day! I will be buying a 19i when my 12 seer kicks it. Why because of the cost savings, comfort and I haven't seen power bills go down. Mine have gone up 75% in 5 years in no way is anything under a 15 seer a good buy.
Well, that may be okay in VA, but in Evansville, WI where GillyWI lives, doing retro work on the home has the biggest return because heating runs many times more hours than cooling during the year.

If the initial cost differential between a 14-SEER & a 19-seer is a lot, & it is NOT installed to the critical letter, - it won't get 15 or 19-seer - It may only deliver 14-seer...


I couldn't find my chart showing hours of cooling runtime a season across the U.S. Here in southern WI I believe it's only around 550 hours, in VA it's probably +1000 or more hours a season; that makes a big difference.

In VA for heating, your above those listed degrees 99% of the time - varies from 12 to 20-F - depending on your location in the state.
 

Last edited by HVAC RETIRED; 08-02-10 at 01:50 PM. Reason: In Evansville, WI where GillyWI lives...
 

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