18 SEER vs 16 SEER HP

[AvantGarde]

Under what circumstances would it pay to pay the extra $ to get extra efficiency?

South
1400 ft2
Load calc calls for 3T

[badtlc]

that all depends on your opinion of what a "worth it" payback period is. It also depends on your electric rates and climate.

[AvantGarde]

that all depends on your opinion of what a "worth it" payback period is. It also depends on your electric rates and climate.

Right now we're paying 12 cents/kwHr and our climate is very warm summers and moderate winters

[beenthere]

Depends on the price difference also.
Which you know we can't discuss.
Look to see if you will ever get a return.
Also, if its a choice between the America Standard 16 and 18, then the 18 is worth it for the better humidity control.

[caincompany]

i thought your house was a 1700sq ft? Extra efficiency would pay say if you lived in California, New York or Florida. Our electric bills around here are some of the cheapest in the country so when you get above say 15-16seer it makes payback a much long process, say probably longer than the life of the unit.

[beenthere]

12 cents a KWH is cheap?

Guess those people that pay 5 cents, don't know how lucky they are.

[Kevin O'Neill]

We pay 6.5 cents to 8.5 cents, depending on which power company we have. But when you add fuel cost adjustment, it adds about 1.5 cents/ KWH. Our co-op told us to expect a January price increase of 15% to 35%, because coal is going up then. Then 10% a year the next 3 years after that. But that is what it is here. Your conditions are different.

I put in a Lennox XP-19 2-ton in my house. It is about 18 SEER & 9 HSPF. When the economy comes back, I expect energy prices to go back up as well.

[skippedover]

"Worth it" is like "Beauty". It's all in the eye of the beholder. Financial considerations are the watchwords for one while carbon footprint is the epitome of concentration for another. Basically you'll be producing either 16 or 18 Btu's of cooling for each 1-watt of electricity purchased to operate the equipment. What that means is that the 18-SEER unit is 12.5% more efficient than the 16-SEER unit under all conditions. How that plays into your actual operating costs and/or energy savings is purely a function of how many cooling hours your system must operate and how much your electricity costs. If you want to minimize your carbon footprint when operating the equipment, then the 18-SEER is clearly more climate friendly operationally. How much energy is used to build an 18-SEER unit versus a 16-SEER unit or to transport one over the other is another whole ball of wax. All depends on where you stand in the ecology spectrum.

[AvantGarde]

i thought your house was a 1700sq ft? Extra efficiency would pay say if you lived in California, New York or Florida. Our electric bills around here are some of the cheapest in the country so when you get above say 15-16seer it makes payback a much long process, say probably longer than the life of the unit.
I was going by the blueprints of the home, including garage

Its 1400 and change

[AvantGarde]

i thought your house was a 1700sq ft? Extra efficiency would pay say if you lived in California, New York or Florida. Our electric bills around here are some of the cheapest in the country so when you get above say 15-16seer it makes payback a much long process, say probably longer than the life of the unit.

So it looks like were gonna wind up around .10 Of course this is a govt operation and I'll just leave it at that.

[gary_g]

Under what circumstances would it pay to pay the extra $ to get extra efficiency?

South
1400 ft2
Load calc calls for 3T

The true answer is at what point in the future does the cost difference between the 2 systems pay for itself in energy savings. If payback is 10 years or less, then maybe it's worth the extra $$. If payback is 20 years, then no.

In most cases, you will never re-coup the additional costs of the highest SEER systems in energy savings compared to a new 14 or 15 SEER system (which is typically 12 EER).

[AvantGarde]

The true answer is at what point in the future does the cost difference between the 2 systems pay for itself in energy savings. If payback is 10 years or less, then maybe it's worth the extra $$. If payback is 20 years, then no.

In most cases, you will never re-coup the additional costs of the highest SEER systems in energy savings compared to a new 14 or 15 SEER system (which is typically 12 EER).

That info really helps to distill alot of the info coming at me. I plan on using HVAC op Cost to crunch the numbers

[caincompany]

Hey Avant, our price on power down the road in Booneville is $.091.

[AvantGarde]

Hey Avant, our price on power down the road in Booneville is $.091.

Our's SHOULD be the same but our local's got to give some walking around $ for the line boys when their not workin'

[caincompany]

Kinda like our city workers, they spend a good portion of their time holding shovels upright and as proping devices.

[gary_g]

Basically you'll be producing either 16 or 18 Btu's of cooling for each 1-watt of electricity purchased to operate the equipment. What that means is that the 18-SEER unit is 12.5% more efficient than the 16-SEER unit under all conditions

I believe that you are confusing SEER with EER. You are describing EER.

Energy Efficiency Ratio = System BTU's / condenser power draw. EER is published by the AHRI at 95F ambient, but it can be calculated at any ambient temp.

SEER is a numbers game based on a fictitious cooling "season". Over 40% of the value of the SEER calc for a system with a variable speed fan in the air handler is at the lowest 2 temps of the represented bin temps: 67F and 72F. Who runs their central a/c systems at these temps? I don't.

Systems with the highest SEER ratings (except for the IQ Drive) are dual stage condensers. These have a higher EER on first stage compared to second stage, which is the reason for the high SEER #.

Take care.

[energy_rater_La]

My utility cost are low for my area.
I pay about .08 per Kwh, my nieghbor pays .06 because he
uses 2,500 Kwh per month, whereas I only use 600 to 700 Kwh.
so, my utility co-op penalizes me for using less Kwh!

Here in the land of de-reuglation my rural area has 3 utility providers, rates vary from .06 to a whopping .14 per Kwh, and these folks get a fuel adjustment cost that doubles the utility costs twice a year.

All that said, I have noticed a few posts from the OP here on the forum, and have a couple of questions.
Where (generally) are you located?
How long to you plan to stay in the home?
Is it new construction, or existing home?
Have you thought about a load calculation on your home
to determine what size system you home requires?

[AvantGarde]

My utility cost are low for my area.
I pay about .08 per Kwh, my nieghbor pays .06 because he
uses 2,500 Kwh per month, whereas I only use 600 to 700 Kwh.
so, my utility co-op penalizes me for using less Kwh!

Here in the land of de-reuglation my rural area has 3 utility providers, rates vary from .06 to a whopping .14 per Kwh, and these folks get a fuel adjustment cost that doubles the utility costs twice a year.

All that said, I have noticed a few posts from the OP here on the forum, and have a couple of questions.
Where (generally) are you located? (We're located near Tupelo MS
How long to you plan to stay in the home?Lord Willin' Forever
Is it new construction, or existing home? 15 y/o
Have you thought about a load calculation on your home Yes, I'd didn't see the calcs but it called for 3T
to determine what size system you home requires?

We're around 1400 ft2 w/good shade (except from 11:00 til 2:00 and windows tinted. Attic=R30
Walls=R19
Sealed alot of the intrusive leaks this past summer
Ridge vent
Typical new home construction of the early 90's

[Kevin O'Neill]

We're around 1400 ft2 w/good shade (except from 11:00 til 2:00 and windows tinted. Attic=R30
Walls=R19
Sealed alot of the intrusive leaks this past summer
Ridge vent
Typical new home construction of the early 90's

Sounds like the old 500 sq ft per ton rule. That is not the same as a load calculation.

[energy_rater_La]

yeah, sq ft per ton

you might want to go the extra distance and have a blower door test on your home to find leakage areas. ductwork can also be tested. once leakage sites are sealed then less tons will be required.

you give pretty definate r-values for your insulation.
if your windows are single paned metal framed the solar heat gain even with the tint will be around .65
air tightness & duct leakage to be determined by testing
this information will get you a more accurate load calculation
which you may have to hire done. if hvac company does load,
you should be provided a copy. most co's will charge for the load calc unless they are getting the job.

if I were you I'd start shopping around for a local company that does load calculations.

3 tons is a lot for 1400 sq ft. our climates are very similar, and in hot humid climates the problem is humidity. With oversized units you never feel cool because the unit does not run long enough to remove humidity.
variable speed units are a good choice because they run mostly in low speed and provide good humidity removal, but still have the capacity to switch to higher speed if needed.
I would trade off on the higher seer for v.s. heat pump.

and remember that a good install will make all the difference.

best of luck

[AvantGarde]

yeah, sq ft per ton

you might want to go the extra distance and have a blower door test on your home to find leakage areas. ductwork can also be tested. once leakage sites are sealed then less tons will be required.

you give pretty definate r-values for your insulation.
if your windows are single paned metal framed the solar heat gain even with the tint will be around .65
air tightness & duct leakage to be determined by testing
this information will get you a more accurate load calculation
which you may have to hire done. if hvac company does load,
you should be provided a copy. most co's will charge for the load calc unless they are getting the job.

if I were you I'd start shopping around for a local company that does load calculations.

3 tons is a lot for 1400 sq ft. our climates are very similar, and in hot humid climates the problem is humidity. With oversized units you never feel cool because the unit does not run long enough to remove humidity.
variable speed units are a good choice because they run mostly in low speed and provide good humidity removal, but still have the capacity to switch to higher speed if needed.
I would trade off on the higher seer for v.s. heat pump.

and remember that a good install will make all the difference.

best of luck

He went room to room w/tape measure looked at the ducts.Checked insulation plugged in a few numbers and**voila** 3T. Of course, that's what I had in the first place.
What SHOULD he have done to properly size for the estimate?

[energy_rater_La]

verified insulation levels, drawn a quick plan of the house with window sizes, types, orientation, and size of overhang. if a room by room load calc was done then each room would be measured, if a whole house calc was done no room by room measurement is needed. (the program I used had a quick load..whole house load
and a detailed room by room load)
somewhere in there he should have taken a look at the existing duct system to make sure that the ducts are ok..or measured them to know what to replace to supply the specified amount of room for each room.