Existing Window Units (UNCLASSIFIED)

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I'm working on an energy audit for a building with old window A/C units. The average age is about 15 years old. Does anybody know where I can find a good estimate for the efficiency of a 15 year old unit?

I know there is a wide range of efficiencies, then and now, depending on how much you are willing to pay. I'm looking something I can reference and file in my report to show where I got my numbers.

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Jeurek's picture
Joined: 2010-10-07
Reputation: 0

I have a little older than that. This figure is from
LBNL-40297 "Energy Data Sourcebook for the U.S. Residential
Sector" also attached where RAC is for room air conditioners.


Jason Glazer's picture
Joined: 2011-09-30
Reputation: 0

Hello John,

I'm not sure if this this is what you?re looking for, but here's a table from a 33-page report (full report attached) by Southern California Edison Company, written in October 2007. It covers a.c. EER values 25 years ago and 15 years ago.

Table 4: 1605.1 (b) Table B-2 Standards for Room Air Conditioners and Room Air-Conditioning Heat Pumps
Appliance Louvered Cooling Capacity Minimum EER
Sides (Btu/hr) Effective Effective
Jan 1, 1990 Oct 1, 2000
Room Air Conditioner Yes < 6,000 8.0 9.7
Room Air Conditioner Yes ? 6,000 - 7,999 8.5 9.7
Room Air Conditioner Yes ? 8,000 - 13,999 9.0 9.8
Room Air Conditioner Yes ? 14,000 - 19,999 8.8 9.7
Room Air Conditioner Yes ? 20,000 8.2 8.5
Room Air Conditioner No < 6,000 8.0 9.0
Room Air Conditioner No ? 6,000 - 7,999 8.5 9.0
Room Air Conditioner No ? 8,000 - 19,999 8.5 8.5
Room Air Conditioner No ? 20,000 8.2 8.5
Room A.C. Heat Pump Yes < 20,000 8.5 9.0
Room A.C. Heat Pump Yes ? 20,000 8.5 8.5
Room A.C. Heat Pump No < 14,000 8.0 8.5

If you want the full report in Word Document format, Google ?Work Paper-Energy Star Room Air Conditioners?, then click & download the URL that shown [DOC] Work Paper-Energy Star Room Air Conditioners. This will be the 33-page 2007 report.

Larry O. Degelman, P.E., FIBPSA
Professor Emeritus of Architecture
Texas A&M University
2206 Quail Run
College Station, TX 77845
ldegelman at suddenlink.net

-----Original Message-----

Larry Degelman's picture
Joined: 2011-10-01
Reputation: 0

This is a great place to start. The 15 year old units certainly won't
be *better
*than these values.

I wonder how much *worse *they might be due to poor installation, corroded
and clogged evaporator and condensing coils and other wear and tear? 20%?

James V Dirkes II, PE's picture
Joined: 2011-10-02
Reputation: 203