Seer

[David C. Macy]

This house had a Trane A/C unit manufactured in 3/06 that appeared to be below the 13SEER that was recommended after 1/22/06.

How do you determine what the SEER is for a unit?

I know we are not supposed to determine the adequacy of the size but this system was not cooling or heating properly. The flow at the register was poor and the temperature of the heat & A/C was also not right.

The installer also ran the PVC pipe right in the middle of a valley. I guess he doesnt know about the 2x10 rule for chimneys and that this will leak. Dumb A..

The house was a single level slab ranch about 2500 Sq, FT. R19 and original 1973 windows.

I recommend an HVAC specialist to evaluate for proper operation, vent pipe location and adequacy of the size of the systems.

I did note the improperly installed roof shingles.

[Roy D. Cooke, Sr]

That looks like asphalt also .
Asphalt is only a temporary fix the sun destroys it in about two years .
Most people who do any thing on a roof know that.

...Cookie

[ldapkus]

How do you determine what the SEER is for a unit?

That's easy.


The SEER of a system is determined by multiplying the steady state energy efficiency ratio (EER) measured at conditions of 82°F outdoor temperature, 80°F dB and 67°F wB indoor entering air temperature by the Part Load Factor (PLF) of the system. (The PLF is supplied by the government.)

Add to this the Part Load Factor (PLF):
The SEER of a system is determined by multiplying the steady state energy efficiency ratio (EER) measured at conditions of 82°F outdoor temperature, 80°F dB/ 67°F wb 50% RH indoor entering air temperature by the “Part Load Factor” (PLF) of the system.
The PLF is a measure of the cyclic performance (CD) of a system and is calculated as follows: CD is Cyclical Data
PLF = 1.00 - (CD X's 0.5)

"The cyclic performance (CD) value in the above equation has been determined by the government to be 0.25." The government contends that the PLF should equal:
[1.00 - (.25 x .5)] = .125
1.00 - .125 = 0.875, which yields: PLF of 0.875

The SEER rating is at only one set of conditions that are NOT typical of what we design for. Summer Outdoor Design varies however, we usually design for 75-F indoors NOT 80-F, also when systems' are downsized properly to achieve long runtimes the Part Load Factor becomes far less of a factor. Always go by the EER Rating NOT the SEER rating because as the SEER goes higher the EER ratio to it drops. Therefore, when the system is sized properly you have have a lot more steady-state continuous runtime cycles & the PLF will be minimized.

Proper system sizing for long runtimes along with a computerized variable speed blower motor to keep the evaporator's heatload capacity rating optimized, would help to achieve more of the BTUH, EER, & SEER Ratings of the unit!


When selecting and installing a new unit. First, make all the changes you can to reduce the heat load/heat loss, --more insulation, etc. Then have a complete room-by-room Manual J. It was jointly developed by the Air Conditioning Contractors of America (ACCA) and the Air-Conditioning and Refrigeration Institute (ARI) heat load/loss calculation done on the house to insure correct sizing of the unit, then a Manual S for selecting the correct sized A/C equipment to meet the design load. Then use the Manual D for correct sizing of the Main and Branch Ducts. Manuals S and D were established by the ACCA. Use design outdoor conditions and daily temperature range exactly for your location per Manual J or ASHRAE Handbook of Fundamentals.

[Joe Funderburk, CMI]

I never report the SEER in my report. I do report if the SEER label has been removed on a new system (a violation of Federal law). I would be shocked if it was manufactured after the date of 1/26/06 and it isn't a 13 minimum.

I could be wrong (and someone will no doubt correct me if so) but I don't think the SEER is related to the cooling or heating ability (that is determined by BTUs). The SEER is a measure of efficiency only, not design adequacy.

[David C. Macy]

Originally Posted by jfunderburk

I never report the SEER in my report. I do report if the SEER label has been removed on a new system (a violation of Federal law). I would be shocked if it was manufactured after the date of 1/26/06 and it isn't a 13 minimum.

I could be wrong (and someone will no doubt correct me if so) but I don't think the SEER is related to the cooling or heating ability (that is determined by BTUs). The SEER is a measure of efficiency only, not design adequacy.

The Seer label was tore off.
The RLA was only 9.5. Max fuse 20A. There was a service log at the interior that stated the refrigerant needed to be recharged 2X.(On a less then 1 year system ?) The outside manufacturer date at the outside unit is 3/06. The furnace is 04. Why is a new A/C & coil installed in 07.

Nothing seemed right about this system. Only a 10 degree drop, poor air flow. The furnace only was providing 75 degree air after 15 minutes of operation.