Thread: A/C EER

How do you find the EER when looking at an A/C condensing unit data plate? Thanks.

It is not on the data plate. You would have to have both the model numbers from the indoor and outdoor unit (assuming a split system) and contact the manufacturer.
Some may list the series as part of the model number but that is not accurate since a specific indoor coil and blower will be needed to achieve that EER.

... and there is far more than the component ratings numbers that go into the "actual" performance to reach good numbers.

ASHRAE certifies performance of systems.

When I am inspecting units, the contractor provides a printed out sheet from AHRI ( AHRI :: Air-Conditioning, Heating and Refrigeration Institute ) which lists the model number of the air handler unit and the model number of the condenser unit rated for the SEER, and if either (of both) are not as shown on the listing sheet I do not approve them - which has happened several times.

Thanks for the replies. Is there a way to get the BTU's from the data plate for the condensing unit or does that come from the manufacturer as well?

Originally Posted by Gary Mohel

Is there a way to get the BTU's from the data plate for the condensing unit

That is usually part of the model number.

Example xxxx042000xx where the "x"s are other codes such as plants, versions, and the "042000" is the number of Btu's, and there are 12,000 Btu's per ton, which would make an 042 or 042000 a 3-1/2 ton unit.

Site for look-up on certified equipment.

AHRI Certification Directory

The reality is that those certified Ratings are meaningless, they only list what can be achieved under a specific condition when ductwork systems are perfectly designed with optimal airflow, etc.

Of course, mismatches are not good, but the performance of certified matches depend entirely on the quality of the install & the duct system airflow & other factors.

There are easy ways to ballpark the actual BTUH & EER performance of a system that ought to be used; not mere possibility figures.

Suggestion:
The quickest way is, if condenser coils are clean, learn the normal temperature splits above the outdoor temp according to the indoor humidity levels, etc.. (That info is on my udarrell HVAC web pages.)
or,
Get a low cost Testo Tester & an anemometer to measure the indoor airflow & ballpark figure actual BTUH & EER - the information on low cost instruments:
Amazon.com: Testo 605-H2 Humidity Stick (RH/Temp/WetBulb) 0560 6054: Home Improvement
Everyone, very low cost anemometer to get airflow FPM Velocities, get it:
http://www.amazon.com/Crosse-Technol.../dp/B0002WZRKE

This should be helpful.
CFM X change in enthalpy X 4.5 = BTUH (Ballpark) Operating Performance & EER
"U Must Right Click Link & open in New Tab"
Wet Bulb Enthalpy Chart

Rules of Thumb for Duct Systems - Hart&Cooley
Optimizing efficiencies:
We could cut residential heating and cooling equipment size in America by 30% to 50% if Contractor's would perform honest Manual J calculations, and provided full credit for every load reducing element or detail they could do prior to equipment sizing, prior to doing the initial load calculation audit.

Air infiltration rate, can be half the load, & should be checked & reduced. Ductwork & "airflow" must be checked & optimized for full nominal BTUH performance. Google search: EER SEER - Darrell - udarrell

Originally Posted by Darrell Udelhoven

The reality is that those certified Ratings are meaningless, they only list what can be achieved under a specific condition when ductwork systems are perfectly designed with optimal airflow, etc.

Actually, those certified ratings are not meaningless, and they do not mean what can be achieved under what conditions.

Those ratings mean that Outdoor Unit A can be used with Indoor Unit B and, under the test conditions (or maybe even under a computer model) perform to the minimum SEER rating ... AND ... that units not listed as suitable for each other were either: a) not tested together; or, b) tested that they did not work sufficiently with each other.

Regardless, the meaningful aspect of the list is that UNLESS the outdoor unit matches the state indoor unit, THERE IS NO RATING which can be applied, thus it is not permissible to use two unrated units together ... i.e., if it ain't listed, don't use those units together.

That is pretty dang "meaningful".

I am totally aware of what you have stated, however, when it comes to what counts, it is meaningless regarding what nominal BTUH that unit, duct system & airflow will produce.

"In respect to actual operating performance," the fact that they are a certified match can be meaningless.

Therefore, both statements are correct, in the context in which each claim is made.

There also could be non-certified matches with TXV metering devices that out perform a certified match, due to all the other factors that determine actual performance having been properly accomplished.

Go out in the field & do an accurate test of, even new installs, installs of certified matching units & see how some will only be doing 60% or so of their Nominal Ratings!

Certainly, it is good to have certified matches, but there are other factors that make the gigantic difference in how close any of them come to meat their nominal ratings.
KUNI: Talk@12 5/26/09 (2009-05-26)
After the Iowa public radio audio page loads, Click on the link & listen to professional Energy Auditors statements on new installs!

Regardless, the meaningful aspect of the list is that UNLESS the outdoor unit matches the stated indoor unit, THERE IS NO [paper] RATING which can be applied, thus it is not permissible to use two unrated units together ... i.e., if it ain't listed, don't use those units together.

That is pretty dang "meaningful". Jerry Peck

We sell 18-SEER units that in the field may only deliver 8 or 9-SEER, it's another pristine laboratory figure that is virtually never matched in the field.
Those Ratings are performed under optimal laboratory conditions & only demonstrate what a perfect install & setup could produce. While in field conditions the ratings don't mean those conditions will be anywhere near replicated.

Yes, I am for the certified matches! I am NOT saying you are wrong, I am saying you are (non-intentionally) skewing the context of the meaning of my stated claims.

I've been working HVAC/R since the early 1970's, first as a tech & later as a contractor/tech doing nearly all the work alone. - Darrell

Originally Posted by Darrell Udelhoven

Yes, I am for the certified matches! I am NOT saying you are wrong, I am saying you are (non-intentionally) skewing the context of the meaning of my stated claims.

Quite to reverse is true and why I restated what I had stated before ... YOU are skewing the context of the meaning of what was being stated on the certified matches.

NOTHING had been said about what certified matches will actually do, nor of what non-matched equipment will do. YOU threw that into the mix, so *I* had to come back and clarify what was being said and its intent.

Originally Posted by Jerry Peck

Quite to reverse is true and why I restated what I had stated before ... YOU are skewing the context of the meaning of what was being stated on the certified matches.

NOTHING had been said about what certified matches will actually do, nor of what non-matched equipment will do. YOU threw that into the mix, so *I* had to come back and clarify what was being said and its intent.

I agree with your stated claim; I threw in the importance of HOW the certified matches performed in respect to some uncertified coil matches due to the quality of the ductwork/airflow & other installation procedures.

You're always right Jerry, therefore I am wrong!

As a longtime tech, I care more about what the actual install delivers & not just its certified potential to deliver under perfect laboratory conditions, though that is important to know, home conditions determine what those certified/matched or even uncertified untested coil setups will deliver.

Sometimes, the money saved by not having to change the coil could be used to upgrade the airflow system & therefore deliver far more BTUs per Hour with higher EER performance, with a TXV metering device coil, -than the certified match with inadequate airflow through the coil.

Making someone appear wrong & you right may be important to you -so, I'll lose so you can win, - however, my clients will be winners when they know the truth concerning the nebulous proven unreliable high SEER Ratings that are also rather meaningless due to the variable field conditions, - plus poor airflow setups, oversized equipment which destroys SEER Rating performance, & so-forth.

Actual TESTED, BTUH & Steady State EER are much more reliable standards of actual performance than the skewed SEER formula speculations... California testing proved SEER Ratings to be an inaccurate predictor of seasonal performance... actual performance is what counts, to the client users, & is what should always be properly tested. - Darrell

While I do believe that the ratings are not etched in stone, they are a fairly good barometer of what the homeowner can expect. Obviously that depends on the install. But just as car manufacturers hype a models MPG, HVAC Co.s can use these numbers to help sell a system. It gives the homeowner a chance to make an informed decision.

Originally Posted by David Bell

While I do believe that the ratings are not etched in stone, they are a fairly good barometer of what the homeowner can expect. Obviously that depends on the install. But just as car manufacturers hype a models MPG, HVAC Co.s can use these numbers to help sell a system. It gives the homeowner a chance to make an informed decision.

The usual oversizing of equipment, bad install setups, etc., change/alter the BTUH & EER (Average MPG) of every residential install/setup.

My many years of experience have taught me that contractor salespersons are selling SEER savings according to those printed charts, & that is not ethical unless you level with customers' & unless the actual performing BTUH & EER is tested.

Far too many things, including oversizing equipment, poor airflow through the indoor coil, etc., causes the nebulous printed SEER Ratings to take a first class nosedive.

I would tell my clients, were I not retired, that SEER Ratings were performed in a laboratory & all home installations including unit oversizing, duct system airflow, air handlers, etc., - vary in ways that can easily completely skew printed SEER Ratings.

It is easy to ballpark test actual performance & provide the owner the approximate BTUH & EER the system is actually delivering, & not some printed SEER that may not be applicable to their home's entirely different conditions or situation. - Darrell

If anybody ever wants to read the AHRI procedure for how SEER ratings are established let me know and I'll e-mail it to you.
I guarantee you'll fall asleep pretty quickly.

From the testing we've done you're pretty much wasting your money on anything over 14 SEER. This has been discovered by measuring actual EER in the field and not through number manipulation.
There are only so many theoretical BTUs of heat that you can remove per pound of refrigerant.
The rest is number manipulation by manufacturers.

How did we ever design and match up HVAC equipment before the DOE standards were put into place?
The performance numbers that are published are not verified at each individual test point rather they are extrapolated off a few base measurements.
It's very common to have the performance specifications indicate one thing while the actual results in the field are different.

What a mess.

Originally Posted by Darrell Udelhoven

I agree with your stated claim;

You're always right Jerry, therefore I am wrong!

Making someone appear wrong & you right may be important to you -so, I'll lose so you can win,

Seems I touched a nerve in you always needing to be right, even when what you posted did not apply to what I was saying and then claimed I was wrong. You obviously needed to defend your input, which was, by the way, good input (as supported by David R above), however your input was not applicable to what I was providing.

Jeez!

Initially, I did not quote your statements, nor was I implying in any way that you were wrong in your statements; I am still not implying that!

I don't demand that everyone has to reply perfectly to the context of what I have stated, - or they are somehow wrong.

In my book, Free Speech allows freedom of expression without requiring perfect agreement with, or absolutely responding in context to my or anyone's statements.

The context of my statements were purposely separate from the context of yours.

I try not to offend anyone... I merely express my experienced findings in the HVAC field.

Again, I was not addressing your statements per se, I never indicated in any way that your statements were wrong; my claims were in a separate, different arena from yours.

You attacked my expression of "meaningless," - as to actual operation performance within totally different conditions. (In respect to actual operating performance in various home environment conditions - "meaningless," i.e., without significant applicable purpose.

That was simply my experienced viewpoint, which had no bearing on your statements ... statements that you did not have to in any way, - defend.

I've said all I'm going to say, - I am defenseless... Do me in...