2010 Second Refrigerator Recycling Program
NV Energy – Southern Nevada
Program Year 2010
Measurement & Verification Report
June 2011
Prepared for:
Prepared by:
3239 Ramos Circle
Sacramento, CA 95827
916-363-8383
TABLE OF CONTENTS
Section
Title
Page
1.
Executive Summary .......................................................................................
ES-1
2.
Project Background ........................................................................................
2-1
3.
M&V Methodology .......................................................................................
3-1
4.
Energy Impact Findings .................................................................................
4-1
5.
Key Findings and Issues ................................................................................
5-1
Appendix A
Survey Form...................................................................................................
A-1
Appendix B
Monthly Savings Tables by Rate Class .........................................................
B-1
Appendix C
Assessments of Effective Useful Life for Refrigerators and Freezers ...........
C-1
i
1. EXECUTIVE SUMMARY
This measurement and verification (M&V) report provides measured and verified energy
impacts achieved by the Second Refrigerator Recycling Program (RRP) that NV Energy offered
to its customers in southern Nevada during 2010.
RRP was a demand side management (DSM) program that offered residential customers $30
rebates for the recycling of secondary refrigerators and freezers during the January to December
2010 program year. This program aimed to remove from the grid old, inefficient refrigerators,
which are often operating in unconditioned spaces such as garages and patios.
Ex post electric savings were determined from detailed analyses of program data extracted from
the NV Energy DataStore (the official tracking database). Analyses of these data by the M&V
contractor (ADM Associates) included a census of model numbers; unit ages; DOE data on kW
draw of recycled equipment; and equipment-degradation models that have been utilized to
evaluate similar recycling programs.
Verified electric impacts were 6,708,238 kWh saved annually, which represents a realization rate
of 73%; 3,315,887 kWh were saved during the 2010 calendar year (first year savings). Critical
peak (or on-peak) demand savings are calculated by month and by rate class; summer critical
peak demand savings provided by this program is 955 kW. A sample size was determined that
allowed measured and verified savings to be determined for the program in southern Nevada
with 5.5% precision at the 90% confidence level. The numbers reported constitute gross
savings.
Table ES-1 Energy Impact Summary
First-Year (2010)
Energy Savings (kWh)
Unit Type
Ex Ante
Ex Post
Refrigerators 4,306,963 3,038,133
Freezers
418,987
277,754
Total
4,725,951 3,315,887
1
Annual Energy
Savings (kWh)
Remaining
Lifetime Energy
Useful
Savings (kWh)
Life
1
(RUL),
Ex Ante
Ex Post
Ex Ante
Ex Post
years
8,377,432 6,109,932
8
67,019,456 48,879,457
814,968
598,305
8
6,519,744 4,786,444
9,192,400 6,708,238
73,539,200 53,665,900
According to the implementation contractor, ex ante energy savings are assumed to be 1,372 kWh per unit per year
(the projected average value for all units) for all refrigerators and freezers in the RRP 2010 population.
Executive Summary
ES-1
2. PROJECT BACKGROUND
The Second Refrigerator Recycling Program (RRP) is designed to help customers reduce their
energy consumption by removing second refrigerators from their homes to recycle them. NV
Energy (NVE) also benefits because the second refrigerator, which is generally more inefficient,
will be permanently removed from the system. The recycling process also includes safe disposal
of environmentally harmful material, providing collateral benefits from the RRP program.
The goal of the program is to reduce the number of old, inefficient refrigerators that customers
have moved to their garages or other locations such as basements and patios. Many areas in
which spare units are placed are not space conditioned, and most refrigerators used in that
environment operate under a heavy thermal load during the summer. This is exacerbated by the
fact the refrigerators are usually old and inefficient. Previous studies by the Environmental
Protection Agency (EPA), the Department of Energy (DOE) and other utilities have determined
that removing these refrigerators, and properly recycling them, performs an energy saving
service.2
In 2010, the program was configured as a turnkey, stand-alone energy efficiency initiative. The
program was advertised to the public via ads, bill stuffers, point-of-sale flyers and media events.
To qualify for the program, refrigerators and freezers were required to be in working condition.
Participating customers received pick-up and removal service in addition to a $30 rebate per
recycled unit.
Removing old, inefficient refrigerators prevents them from being resold or transferred to another
NVE customer. The program provides annual electric energy savings for the remaining life of
the unit by permanently removing the unit from service. As an added environmental benefit,
95% of the materials from these units are able to be recycled (metals, plastic, glass, oil, etc.) and
disposed of in an environmentally responsible manner (hazardous materials), thus preventing the
materials from reaching landfills and contaminating the environment.
2
EPA information available at http://www.epa.gov/ozone/title6/608/disposal/household.html
Project Background
2-1
3. M&V METHODOLOGY
This chapter provides a description of the M&V methodologies applied by ADM in the
evaluation of the 2010 RRP. The M&V approach for the RRP is aimed at measuring the
following:

Numbers of refrigerators and freezers collected and recycled;

Percentage of units still operable when recycled;

Date the unit was unplugged;

Average annual kWh savings per collected appliance; and

Average kW reduction per collected appliance.
3.1
VERIFICATION OF UNITS RECYCLED
A first aspect of conducting measurements of program activity is to verify the numbers of
refrigerators and freezers collected and recycled. Our verification effort was threefold,
consisting of:
1) Validating tracking data in the DataStore, checking for duplicate or erroneous entries;
2) Conducting verification surveys with a statistically valid sample of program participants; and
3) Verifying that refrigerators and freezers are recycled according to the process agreed-upon
between JACO and NVE..
As the first step in the verification, data for the program reported in the DataStore were
reviewed. No duplicate entries were discovered. The numbers of refrigerators and freezers
reported in the DataStore as being recycled during 2010 are shown in Table 3-1.
Table 3-1 Numbers of Refrigerators and Freezers Reported in DataStore
as Being Recycled in Southern Nevada in 2010
Unit Type
Refrigerator
Freezer
Total
Quantity Reported
as Recycled
6,106
594
6,700
ADM conducted telephone interviews with a sample of participants in the program to obtain
information with which to determine the percentage of units that were still operable when picked
up by the recyclers via. A random sample, stratified by appliance type (refrigerator or freezer),
was selected to ensure that 90% confidence with 10% relative precision (or better) would be
achieved for each type of unit.
M&V Methodology
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
For the calculation of sample size, a coefficient of variation of 0.5 was assumed. 3 On this
assumption, a sample size of 68 participants is required, as shown in the following formula.
Minimum Sample Size Formula for 90% Confidence
1.645∗𝐶𝑉 2
𝑛0 = (
𝑅𝑃
1.645∗0.5 2
) =(
0.10
) = 68
where:
n0 = minimum sample size
CV = Coefficient of Variation (assumed to be 0.5)
RP = Relative Precision (0.10)
ADM actually conducted phone surveys with 80 customers who recycled refrigerators and 70
who recycled freezers, which provided results at the program level of 5.5% relative precision at
the 90% confidence interval. The goals of the survey were (1) to assess whether any non-eligible
units were recycled and (2) to assess participant satisfaction with the program. The questionnaire
that was the instrument for the survey interviews in provided in Appendix A.
All 150 respondents who were interviewed verified that they had in fact recycled a refrigerator or
freezer through the program. Of the 80 customers who recycled a refrigerator, 71 (88.8%)
indicated that the refrigerator was in working condition. Of the 70 customers who recycled a
freezer, 67 (95.7%) indicated that the freezer was in working condition.
Recycling procedures and unit operation at the time of recycling were verified through ridealongs that ADM staff made for pick-ups. All of the units observed being picked up during the
ADM ride-alongs were verified to be operational. ADM also visited the North Las Vegas
recycling center and verified operations there.
Based on the results from the telephone survey and the ride-along visits, ADM determined that it
was appropriate to apply the following verification rates for the refrigerators and freezers
recycled through the program during 2010. (Verification rates represent the percentage of units
recycled through the program that were in working condition and therefore program-eligible.,)
 Verification rate for refrigerators:
88.8%
 Verification rate for freezers:
95.7%
3
The coefficient of variation, cv(y), is a measure of variation for the variable to be estimated. Its value depends on
the mean and standard deviation of the distribution of values for the variable (i.e., cv(y) = sd(y)/mean(y)).
Essentially, cv is a metric of how wide the distribution of values for the variable of interest is.
As set out in the Model Energy Efficiency Program Impact Evaluation Guide3:
Until the actual mean and standard deviation of the population can be estimated from actual
samples, 0.5 is often accepted as an initial estimate for cv. The more homogenous the population,
the smaller the cv.
Using a cv = 0.5 is also in accordance with California Evaluation Protocols for homogenous measures.
M&V Methodology
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
Based on these verification rates, Table 3-2 reports the numbers of refrigerators and freezers
recycled through the program during 2010 that were verified as being in working condition when
recycled and therefore program-eligible.
Table 3-2 Numbers of Refrigerators and Freezers
Recycled through Program in 2010 and Verified in Working Condition
Unit Type
Refrigerator
Freezer
Total
3.2
Quantity Reported
as Recycled
Verification
Rate
6,106
594
6,700
88.8%
95.7%
Quantity of Recycled
Units Verified as
in Working Condition
5,422
569
5,991
CALCULATING ANNUAL KWH SAVINGS PER APPLIANCE
The implementer for NVE’s Second Refrigerator Recycling Program projected ex ante savings
for recycled units by taking the manufacture’s estimate of annual kWh usage for a recycled unit
and increasing that to reflect at-death energy usage, based on an assumed equipment degradation
factor. For the M&V effort, this procedure was examined with respect to (1) the assumed
degradation factor and (2) the accuracy of energy use as calculated through the DOE test
procedure.
ADM’s review of available literature and data showed that that the degradation coefficients
applied by the implementer were at the upper-end of the range of coefficients observed in other
similar studies. Based on the large amount of metered data analyzed and its comprehensive
nature, ADM determined that a more appropriate equipment-degradation factor could be
developed using data and analysis prepared by The Cadmus Group in a 2009 study on
refrigerator degradation for the California Public Utilities Commission.4
For its study, Cadmus used data on refrigerator / freezer energy use obtained through two in situ
monitoring efforts:


A dual monitoring study that ADM conducted in support of the evaluation of the (California)
2004-2005 Statewide Residential Appliance Recycling Program; and
Additional in situ monitoring that Cadmus conducted as part of its study.
The product of these efforts was a database that contained energy use obtained through both
DOE testing and in situ monitoring for a sample of 321 units, 184 of which were from the 20042005 evaluation and 137 from the 2006-2008 evaluation. Cadmus used the data from this dual
monitoring sample to develop regression models that relate in situ energy use to energy use as
4
The Cadmus Group, Inc. “Residential Retrofit High Impact Measure Evaluation Report”, prepared for the
California Public Utilities Commission. February 7, 2010.
M&V Methodology
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
determined from the DOE test procedure and modification factors based on weather and
household size. These modification factors are summarized in Table 3-3.
Table 3-3. In Situ Monitoring Adjustments to DOE Testing Values
Primary
Yes
Household
Size
1-2
3+
No
1-2
3+
Climate Zone
N
Cool
Warm
Cool
Warm
Cool
Warm
Cool
Warm
29
18
50
32
86
42
59
31
% In Situ
Delta5
-30.8%
-19.2%
-16.0%
-6.4%
-21.3%
-15.8%
-6.8%
1.3%
For this M&V study, Southern Nevada is treated as a Warm Climate. Because distribution of
household sizes is not known for the population of customers participating in the RRP, the
distribution observed in the Cadmus study was used. As this program focuses on second
refrigerator recycling, the figures used in the calculations to follow are drawn from Table 3-1
where Primary = “No”. There were 42 households with 1-2 people and 31 with 3+. Weighting
the “% In Situ Delta” by these values, we get an adjustment factor of:
[(42/73) x -15.8%] + [(31/73) x 1.3%] = -8.54%
Using these analytical results, it was determined that annual kWh increases by 1.25% per year
because of equipment degradation. The final result is then reduced by 8.54% in order to account
for the effects of weather and household size calculated in the Cadmus study. Therefore the
annual energy savings (kWh) for the population of refrigerators and freezers in the RRP is
calculated using the following equation:
𝑵
𝑬𝒏𝒆𝒓𝒈𝒚 𝑺𝒂𝒗𝒊𝒏𝒈𝒔 (𝒌𝑾𝒉)𝑨𝒏𝒏𝒖𝒂𝒍 = ∑ 𝑿 ∗ 𝟏. 𝟎𝟏𝟐𝟓𝒚 ∗ (𝟏 − 𝟎. 𝟎𝟖𝟓𝟒)
𝒏=𝟏
where
X is per unit rated annual kWh usage at time of manufacture, i.e., prior to degradation
1.0125 is the degradation coefficient of 1.25% per year
y is age of unit, i.e., years since manufacture
0.0854 is the weather/household effects coefficient (from referenced Cadmus study)
5
A negative in situ delta represents an in situ UEC that is lower than the DOE UEC
M&V Methodology
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
A further adjustment was made to account for some of the appliances that were recycled not
being used throughout the entire year. An adjustment to gross savings was therefore appropriate
for such units to reflect this part use (i.e., the proportion of a year that a given recycled appliance
had been used rather than switched off). Different values for use factors were assigned based on
three categories into which recycled refrigerators fall.

Some units that were recycled were not being used at all before being sent for recycling. The
use factor for such units therefore would 0. That is, these units were not being used even
before recycling and therefore had no energy use.

Other units were being used, but for only part of the year. For these units, the use factor is
calculated by dividing the number of months in the past year that the unit had been plugged
in and running by the number of months in the year (i.e., 12). Based on data collected
through the survey of participants, the average number of months in use for a refrigerator that
was being partly used was 7.3 months, implying a use factor of 0.611 (i.e., 7.3/12). For
freezers in this category, the use factor was calculated to be 0.222, reflecting an average of
2.7 months in use for freezers being partly used.

Units used all of the time have a use factor of 1.
The overall use factor and the corresponding overall Unit Energy Savings (UES) are calculated
as a weighted average across the three categories, where the weights are determined by the
percentages of units falling into the three categories. Table 3-4 shows the calculation of the
overall UESs for refrigerators and freezers when part use is accounted for.
Table 3-4. Calculation of Unit Energy Savings Adjusted for Part Use
Operating Status
of Unit
Percentage of
Recycled Units
in Category
Use Factor
Calculation
of UES
to Adjust
for Part Use
Refrigerators
Not running
0
Running part time
3.8%
0.611
Running all time
96.2%
1.000
Weighted Average UES for Refrigerators
0
286
1,144
1,127
Freezers
Not running
2.9%
Running part time
4.3%
Running all time
92.8%
Weighted Average UES for Freezers
0.000
0.222
1.000
0
249
1,123
1,053
The above procedure can be summarized as follows: Each appliance in the population starts with
a kWh usage at time of manufacture. This kWh value is then degraded based on unit age and
other factors that affect the unit’s efficiency over time. The kWh for each unit is further adjusted
M&V Methodology
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
(1) to represent in situ usage, as opposed to a DOE laboratory setting and (2) to take account of
some units being used only part of the year. Finally, the adjusted kWh values for each unit are
summed over the population to represent total program savings.
3.3
CALCULATING FIRST-YEAR KWH SAVINGS
First-year kWh savings were calculated by determining what percent of the year was remaining
when the unit was recycled. Based upon our surveys with participants, we determined on
average that the units were unplugged one week prior to recycling. As such, we subtracted one
week from the recycling data listed in the DataStore tracking data, and calculated how many
days were left in the year following unplugging. The remaining time in service was then used
along with load shapes for refrigerators in the Reno climate zone in determining the share of
annualized kWh savings realized in the 2010 program year. After first-year kWh was calculated
for each unit individually, they were then summed in order to determine program-level first-year
kWh savings.
3.4
CALCULATION OF CRITICAL PEAK DEMAND SAVINGS
The three-hour critical peak demand period per month for NPC (NV Energy South) is defined as
the maximum average hourly demand during the three consecutive hours per month shown
below in Table 3-5. For example, the three-hour critical peak (or on-peak) period during July is
the maximum average hourly demand from 16:00 hours or 4:00 PM to 18:59 hours or 6:59 PM.
Table 3-5. Critical Peak Demand Period per Month, NPC
NPC (NV
Energy South)
Three-Hour Critical Peak Period
Hour 1 begins at:
Hour 2 begins at:
Hour 3 begins at:
January
18:00
19:00
20:00
February
March
April
May
June
July
August
September
October
November
December
18:00
19:00
20:00
19:00
20:00
21:00
16:00
17:00
18:00
16:00
17:00
18:00
16:00
17:00
18:00
16:00
17:00
18:00
15:00
16:00
17:00
16:00
17:00
18:00
13:00
14:00
15:00
18:00
19:00
20:00
18:00
19:00
20:00
Critical peak demand savings (kW savings) are calculated by month and by rate class, utilizing
ex post program savings calculations and appropriate measure-level, 8760-hour load shapes. For
each 2010 participant in this program, ex post annualized energy savings per measure is allocated
M&V Methodology
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
to the specific rate class for that participant, and to the specific load shape for that measure. The
result is a two dimensional matrix providing per-rate-class savings per hour for all 8760 hours of
the typical calendar year. We then inspect the results for each month to identify the maximum
average hourly demand during the three consecutive hours per month shown in Table 3-5. The
complete ex post determinations for critical peak demand savings (kW savings) per month and
per rate class are provided in Appendix B.
3.5
DETERMINATION OF EFFECTIVE USEFUL LIFE (EUL)
ADM determined that an EUL of eight years was a reasonable and relatively conservative6 value
for the population of refrigerators and freezers that were recycled through this program.
Appendix C presents the results of analyses used to derive effective useful life assessments for
refrigerators and freezers.
6
Based on its analyses of data extracted from the 2009 Residential Appliance Saturation Survey (RASS) conducted
in California, ADM determined that one could argue on behalf of average measure lives of as high as 10.86 years
for both refrigerators and freezers.
M&V Methodology
3-7
4. ENERGY IMPACT FINDINGS
This chapter provides detailed results pertaining to the energy impacts of the program during
2010.
4.1
ENERGY IMPACTS AND VARIANCES
Table 4-1 presents ex ante and ex post energy savings, along with program-year realization rates,
both disaggregated between refrigerators and freezers as well as the aggregated totals.
Table 4-1. Annual Energy Impact Summary
Unit Type
Ex Ante Energy
Savings (kWh)
Refrigerators
Freezers
Totals
8,377,432
814,968
9,192,400
Ex Post Energy
Savings (kWh)
6,109,932
598,305
6,708,238
Variance
Realization Rate
-2,267,500
-216,663
-2,484,162
73%
73%
73%
Table 4-2 summarizes the first-year kWh impact of the 2010 RRP in southern Nevada. As stated
in the methodology section, this is based on the recycling dates listed, with the annual savings
per unit scaled by the percentage of the year remaining subsequent to their removal from service.
Table 4-2. Lifetime Energy Savings Summary (Ex Post)
First-Year
(2010) Energy
Savings (kWh)
Unit Type
3,038,133
277,754
3,315,887
Refrigerators
Freezers
Total
4.2
Annual Energy
Savings (kWh)
6,109,932
598,305
6,708,238
Remaining
Useful Life
(RUL), Years
8
8
Lifetime Energy
Savings (kWh)
48,879,457
4,786,444
53,665,900
IMPACT BY RATE CLASS
Refrigerators and freezers recycled through the program provide savings in three rate classes.
These classes, along with their share of annual kWh savings realized through the RRP, are as
follows:

RS:
87.49%

RSL:
0.03%

RM:
11.10%

ORMTOU:
0.07%

ORSTOU-A:
1.30%
Energy Impact Findings
4-1
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
The resulting savings by rate class are presented in Table 4-3 below.
Table 4-3. Energy Impacts by Rate Class
Rate Class
RS
RSL
RM
ORMTOU
ORSTOU-A
Total
First-year (2010)
Energy Savings
(kWh)
2,883,421
793
390,183
1,137
40,353
3,315,887
Annual Energy
Savings (kWh)
5,869,335
2,001
744,790
5,003
87,109
6,708,238
Lifetime Energy
Savings (kWh)
46,954,677
16,010
5,958,316
40,026
696,871
53,665,900
Additionally, ADM determined monthly savings results for the first year and for years 2011
through 2013. These results are provided in Appendix B.
Energy Impact Findings
4-2
5. KEY FINDINGS AND ISSUES
This chapter presents key findings and issues.
5.1
SUMMARY OF KEY FINDINGS
Key findings from the M&V work were as follows.
The first and foremost key finding pertains to the degradation factor used by the implementer.
This factor is at the upper-tier of degradation factors reported in other studies. The factor
assumed by the implementer was based on a study of public housing in New York conducted in
1998. That may cause issues of transferability to this program, as the NV Energy RRP is
primarily focused on the private residential market. Research into more recent analyses of
refrigerator degradation indicates that the appropriate annual degradation factor would be 1.25%,
lower than the 1.37% figure used in the ex ante projections.
A second key finding was that a correction factor based on in situ monitoring resulted in savings
being reduced by 8.54%, with this attributable to a statistically significant sample of monitoring
under normal operating conditions as opposed to DOE laboratory conditions.
The final result was a realization rate of 73%, with results of:

6,708,238 kWh savings per year;

3,315,887 First-Year kWh Savings; and

955 Summer Critical Peak kW Savings.
5.2
SUMMARY OF KEY ISSUES
An issue that arose during the M&V effort pertained to the reporting of data to NV Energy’s
DataStore tracking database by the implementation contractor. Specifically, data on participant
phone numbers, unit configuration (side-by-side, top freezer, etc.), or unit defrost type were not
included in the reporting to the DataStore. Because data for these fields were not reported in the
DataStore, these data were acquired directly from the implementer. Collecting the data directly
from the implementer enabled ADM to complete all requisite aspects of its evaluation of energy
impacts despite some data not being reported in the DataStore. However, the M&V effort would
be more efficient if the data were available in the Data Store.
The M&V work for the RRP program would be facilitated if more information on unit
configuration and defrost type were recorded in the DataStore. In addition, conducting the
survey portion would be easier if phone numbers were uploaded along with the rest of the
customer information, rather than being part of a separate database. Finally, the ex ante energy
savings values reported in the DataStore should represent the ex ante values that the implementer
expects ADM to use for the purpose of ADM’s impact evaluation.
Key Findings and Issues
5-1
APPENDIX A
SURVEY FORM
This appendix provides a copy of the survey form used in the telephone surveys.
NV Energy
Second Refrigerator Recycling
Participant Survey Questionnaire
Interviewer: _____________________
Date of Interview: _____/_____/_____
Respondent:
Address: ________________________
____________________
Hello. My name is _____, and I am calling on behalf of NVE. I am conducting a brief survey regarding
NVE’s Refrigerator Recycling Program. May I ask you a few questions?
1. Do you recall having one of your old refrigerators or freezers picked up for recycling?
___ Yes
___ No (if no, thank the respondent and terminate the interview)
2. How did you first hear about the NVE Refrigerator Recycling Program?
a. Retailer
b. Newspaper or magazine ad/article
c. TV ad
d. Friend or relative
e. NVE website
f.
NVE brochure
g. NVE bill insert
h. Don’t Know (Don’t Read)
i.
Other (Specify)
3. When was the old refrigerator picked up?
_______________ (month and year)
Appendix A: Survey Form
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
4. When did you learn about the NVE Refrigerator Recycling program and the available rebate?
a. Before deciding to recycle the refrigerator
b. After deciding to recycle the refrigerator
c. At the same time as deciding to recycle the refrigerator
d. Don’t Know (Don’t read)
5. Why did you want to get rid of your old refrigerator/freezer?
a. Bought a replacement
b. Didn’t need it anymore
c. It didn’t work anymore
d. It cost too much to run
e. Other: __________________________________________________________________
6. Was the old refrigerator still in working condition when it was picked up?
___ Yes
___ No (skip to #8)
7. Was the old refrigerator still being used when it was picked up? (If respondent says no, ask probing
question, i.e., “Was it in use prior to calling NVE for recycling?”, “When did you stop using the
refrigerator (month/yr)?”
___ Yes, all of the time
___ Yes, some of the time
___ No
7b. If “Some of the time” – Approximately how many months out of the year was the refrigerator in
use?
8. What month/year was the refrigerator last plugged in?
_______________ (month and year)
9. Did you have specific plans to recycle the refrigerator prior to learning of the NVE Refrigerator
Recycling Program?
___ Yes
___ No
Appendix A: Survey Form
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Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
10. What would you have done with your old refrigerator if you had not recycled it thru NVE?
a. Continued to use it
b. Sold it
c. Unplugged and stored it
d. Junked it
e. Given it away
f.
Other: _________________________________________________________________
11. How old was your old refrigerator/freezer at the time you recycled it? __________ Years Old
12. 12. When the refrigerator was in use, where in the house was it set up? (Prompt only if necessary)
a. Kitchen
b. Den/Lounge
c. Garage
d. Basement
e. Other (specify) _______________
13. Have you ever needed to replace a major appliance before?
___ Yes
___ No (skip to #15)
14. When replacing a major appliance, what do you typically do with the old unit (Prompt only if
necessary)?
a. Take for recycling
b. Dispose at a dump
c. Give to friend/family
d. Donate to Charity
e. Sell the appliance
f.
Other (Explain)
Appendix A: Survey Form
A-3
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
15. If NVE had not offered a rebate for recycling the refrigerator, how likely would you have been to
recycle the refrigerator anyway?
a. Definitely would have recycled
b. Probably would have recycled
c. Definitely would not have recycled
d. Definitely would not have recycled
e. Don’t know
16. How important was the rebate in your decision to recycle the refrigerator?
a. Very Important
b. Somewhat Important
c. Slightly Important
d. Not at All Important
e. Don’t Know (Don’t Read)
17. How satisfied were you with the rebate you received for recycling your old refrigerator/freezer?
a. Very Satisfied
b. Somewhat Satisfied
c. Somewhat Unsatisfied
d. Very Unsatisfied
e. Don’t Know
18. How satisfied were you with the length of time it took to receive the rebate for recycling your old
refrigerator/freezer?
a. Very Satisfied
b. Somewhat Satisfied
c. Somewhat Unsatisfied
d. Very Unsatisfied
e. Don’t Know
Appendix A: Survey Form
A-4
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
19. How satisfied were you with the scheduling of the pick-up of your old refrigerator/freezer?
a. Very Satisfied
b. Somewhat Satisfied
c. Somewhat Unsatisfied
d. Very Unsatisfied
e. Don’t Know
20. How satisfied were you with the overall recycling process for your old refrigerator/freezer?
a. Very Satisfied
b. Somewhat Satisfied
c. Somewhat Unsatisfied
d. Very Unsatisfied
e. Don’t Know
21. (If Unsatisfied for Q17, Q18, Q19 or Q20) Why were you unsatisfied with the (rebate, scheduling,
length of time to get the rebate, or overall) recycling of your old refrigerator?
___________________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
22. Do you have any specific comments or suggestions about how to improve the Refrigerator Recycling
Program?
Appendix A: Survey Form
A-5
APPENDIX B
MONTHLY SAVINGS TABLES BY RATE CLASS
This appendix provides monthly savings by rate class for the years 2010-2013.
Table B-1 Monthly Savings by Rate Class - 2010
Rate Class
Jan
Feb
Mar
RS
13,969
39,179
75,948
-
-
-
RSL
RM
2,447
7,215
-
ORMTOU
Apr
111,567
ORSTOU-A
104
319
759
Total
16,520
46,712
89,499
-
24,698
-
Jul
227,528
-
18,471
-
Jun
166,418
-
12,792
-
May
32,117
-
Aug
Sep
Oct
Nov
Dec
Total
305,571
358,133
376,030
395,092
386,933
427,051
2,883,421
60
97
166
169
151
150
793
41,381
46,944
48,544
50,697
50,282
54,595
390,183
6
193
179
169
216
375
1,137
-
1,180
2,312
3,294
4,061
4,803
5,628
5,872
5,647
6,373
40,353
131,218
193,429
262,939
351,080
410,170
430,548
451,999
443,229
488,543
3,315,887
Nov
Dec
Table B-2 Monthly Savings by Rate Class – 2011
Rate Class
RS
Jan
Feb
438,596
Mar
411,405
Apr
458,304
May
478,690
Jun
512,206
Jul
535,195
Aug
567,304
Sep
561,972
Oct
521,517
494,905
445,803
Total
443,438
5,869,335
RSL
148
139
155
163
175
184
195
193
179
169
151
150
2,001
RM
55,486
52,093
58,040
60,729
65,033
68,068
72,190
71,497
66,289
62,787
56,464
56,114
744,790
370
348
388
408
437
460
488
483
447
422
378
375
5,003
6,509
6,106
6,802
7,104
7,602
7,943
8,420
8,340
7,740
7,345
6,616
6,581
87,109
501,110
470,092
523,690
547,095
585,453
611,849
648,596
642,486
596,171
565,627
509,412
506,657
6,708,238
ORMTOU
ORSTOU-A
Total
Appendix B: Monthly Savings by Rate Class
B-1
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
Table B-3 Monthly Savings by Rate Class – 2012
Rate Class
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Total
438,596
426,190
458,304
478,690
512,206
535,195
567,304
561,972
521,517
494,905
445,803
443,438
5,884,119
RSL
148
144
155
163
175
184
195
193
179
169
151
150
2,006
RM
55,486
53,966
58,040
60,729
65,033
68,068
72,190
71,497
66,289
62,787
56,464
56,114
746,662
RS
370
361
388
408
437
460
488
483
447
422
378
375
5,016
6,509
6,325
6,802
7,104
7,602
7,943
8,420
8,340
7,740
7,345
6,616
6,581
87,328
501,110
486,986
523,690
547,095
585,453
611,849
648,596
642,486
596,171
565,627
509,412
506,657
6,725,132
ORMTOU
ORSTOU-A
Total
Table B-4 Monthly Savings by Rate Class - 2013
Rate Class
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Total
438,596
411,405
458,304
478,690
512,206
535,195
567,304
561,972
521,517
494,905
445,803
443,438
5,869,335
RSL
148
139
155
163
175
184
195
193
179
169
151
150
2,001
RM
55,486
52,093
58,040
60,729
65,033
68,068
72,190
71,497
66,289
62,787
56,464
56,114
744,790
370
348
388
408
437
460
488
483
447
422
378
375
5,003
6,509
6,106
6,802
7,104
7,602
7,943
8,420
8,340
7,740
7,345
6,616
6,581
87,109
501,110
470,092
523,690
547,095
585,453
611,849
648,596
642,486
596,171
565,627
509,412
506,657
6,708,238
RS
ORMTOU
ORSTOU-A
Total
Appendix B: Monthly Savings by Rate Class
B-2
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
June 2011
Table B-5 Critical Peak Demand (kW) Reduction per Month per Rate Tariff
Rate Class
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
624
650
668
762
789
835
828
823
803
761
661
654
RSL
0
0
0
0
0
0
0
0
0
0
0
0
RM
79
82
85
97
100
106
106
105
102
97
84
83
RS
ORMTOU
1
1
1
1
1
1
1
1
1
1
1
1
ORSTOU-A
9
10
10
11
12
12
12
12
12
11
10
10
713
743
764
872
902
955
947
941
918
870
755
747
Total
Appendix B: Monthly Savings by Rate Class
B-3
APPENDIX C
ASSESSMENTS OF EFFECTIVE USEFUL LIFE
FOR REFRIGERATORS AND FREEZERS
This appendix presents and discusses the results of analyses used to derive effective useful lives
for refrigerators and freezers.

Section C.1 describes the analytical methods used.

Section C.2 provides survival functions based on analysis of data extracted from the 2009
Residential Appliance Saturation Survey conducted in California.
C.1
ANALYTICAL METHODS
Determining the effective useful life of recycled refrigerators and freezers requires determining
those same units’ remaining useful lives had they been left in service rather than recycled.
Remaining useful life can be inferred using a survival function for refrigerators or freezers,
where a survival function shows the fraction of installed measures still in place and operable as
time passes.
The analytical difficulty that arises in deriving a survival function for refrigerators and freezers is
that the amount of data available is relatively limited. It can be assumed that 100% of the units
are in place and operable when they are installed. Moreover, the retention rates for refrigerators
and freezers are relatively high in the early years of their lives. Because of this, non-parametric
methods of assessing survival functions are not appropriate. That is, non-parametric methods can
give an accurate assessment of median survival time only if more than 50% of the measures are
no longer in place and operable.
With parametric methods for assessing survival times, a survival function is calculated using the
available data and the calculated function is then used to project survival rates at future points in
time. The difficulty with the parametric approach is that the high early retention rates for
refrigerators and freezers mean that there is little information with which to distinguish between
different functional forms for the survival function. Because of the limited time span that the
collected data cover, a variety of survival functions that imply significantly different median
lives can be fitted through the data.7
To overcome these difficulties, other assessments of survival functions for refrigerators and
freezers were developed using data for households in California that were collected in the 2009
California Residential Appliance Saturation Survey. These data are used because they show both
7
For discussion of this problem, see Hahn, G.J. and Meeker, W.Q, Jr., “Pitfalls and Practical Considerations in
Product Life Analysis—Part I: Basic Concepts and Dangers of Extrapolation”, Journal of Quality Technology,
Vol. 14, July 1982, pp. 144-152.
Appendix C
C-1
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011
the age distribution of the existing stocks of refrigerators and freezers and also the numbers of
refrigerators and freezers discarded within a year.
The steps in the procedure for calculating the survival functions were as follows:

Prepare data for calculation of hazard rate function

Calculate hazard rate function

Use hazard rate function to determine survival function

Use survival function to develop life tables that show remaining useful lives for refrigerators
and freezers at different ages

Impute remaining useful lives for refrigerators and freezers recycled through NV Energy’s
refrigerator recycling program
An essential component in this analytical procedure is the calculation of the hazard rate function.
A hazard function defines the probability that an item will fail in the next unit of time, given that
it has survived to the present. The hazard rate at time t is the ratio of the number of units failing
in that interval to the number surviving to that time:
f(t)
h(t) = 1-F(t)
where h(t) is the hazard rate at time t; f(t) is the probability of failure during an increment of time
at time t; and F(t) is the cumulative probability of failure up to time t. Once a hazard function is
calculated, a corresponding survival function S(t) can be determined, where S(t) represents the
percent surviving at time t.8
Two of the distributions commonly used for survival analysis are the exponential distribution
and the Weibull distribution9. The probability density functions and associated hazard functions
and survival functions for these distributions are shown in Table C-1.
Table C-1. Hazard and Survival Functions for Exponential and Weibull Distributions
Exponential Distribution
f(t) = exp(-t)
h(t) = 
S(t) = exp(-t)
Probability Density Function
Hazard Function
Survival Function
Weibull Distribution
Probability Density Function
Hazard Function
Survival Function
F(t) = t-1exp(-t)
h(t) = t-1
S(t) = exp(-t)
8 Collette, D. Modeling Survival Data in Medical Research, Chapman & Hall, 1994, pp. 10-13.
9 Collette, ibid. Also see Kiefer, Nicholas “Economic Duration Data and Hazard Functions”, Journal of Economic
Literature, Vol. XXVI, pp. 646-679, June 1988.
Appendix C
C-2
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011
As Table C-1 shows, the exponential distribution can be used to represent a hazard rate that is
constant. The associated survival function is also exponential. However, the exponential
distribution does not represent hazards that increase or decrease over time. Previous studies have
shown that hazard rates for refrigerators and freezers do increase with the age of the units.
Accordingly, the Weibull distribution was used to represent the hazard function and the survival
function because it can accommodate hazard rates that differ with age. (Note that with the
Weibull distribution,  is termed as the scale parameter, while  is termed as the shape
parameter.)
C.2
ANALYSIS OF EFFECTIVE USEFUL LIVES USING RASS DATA
Alternative assessments of EULs for refrigerators and freezers were developed by using data for
households from the 2009 Residential Appliance Saturation Survey (RASS) that was conducted
in California. Respondents to this survey provided information about their ownership of
refrigerators, about the ages of those appliances or equipment, about whether they had discarded
a refrigerator or freezer during the past year, and about the age of the discarded refrigerator or
freezer. The RASS data provided the information needed to develop calculations of hazard
functions and survival functions for refrigerators and freezers.
Table C-2 shows how data from the California RASS were used to calculate a hazard function
for refrigerator discards. For this example, data for households in the service territory of
Southern California Edison were used.
Table C-2. Data Used for Calculation of Hazard Function for Refrigerator Example
(1)
Age
of
Refrigerator
Less than two years
2 – 7 years
8 – 10 years
11 – 20 years
More than 20 years
(2)
(5)
(6)
Percentage Annual
of Discards Percentage
Stock
Calculated Annual
Taken of Discards
of
Annual Percentage
Out
Taken
Refrigerators Discards Discarded
of
Out of
Stock
Stock
912
2,492
1,214
828
142
(3)
32
87
42
149
60
(4)
3.5%
3.5%
3.5%
18.0%
42.6%
34.6%
48.7%
43.3%
51.4%
49.0%
1.21%
1.70%
1.51%
9.26%
20.90%
The data in Table C-2 were developed through the following steps.

On the questionnaire used for the 2009 California RASS, respondents were asked to classify
the ages of their refrigerators according to the age categories shown in Column (1). The
stock of refrigerators in each age category, as determined from the weighted RASS data, is
shown in Column (2).
Appendix C
C-3
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011

RASS respondents were asked if they had discarded a refrigerator in the previous year and, if
so, to provide information on the age of the refrigerator discarded. Using the age data, the
distribution of discards across the age categories in Column (1) could be determined. The
annual number of discards by age category is reported in Column (3).

Refrigerator discards for each age category as a percentage of the stock in a category are
shown in Column (4).

To determine the percentage of discards taken out of stock, survey information that was
made available by KEMA was used. As part of their work in preparing a ninth-year retention
study for SCE’s Residential Appliance Recycling Program (RARP), KEMA conducted a
telephone survey of a sample of SCE customers who reported in the 2002 California RASS
that they had discarded a refrigerator in the past year. In the KEMA survey, a respondent
who reported that a refrigerator was discarded was asked several questions as to how the
refrigerator was disposed of. For this study, a discarded refrigerator was assumed to be taken
out of stock if one of the following conditions applied.
 If the discarded refrigerator was no longer in working condition; or
 If a respondent indicated that the refrigerator was recycled through a utility recycling
program or was taken to a scrap dealer, recycler, or landfill.
The percentages of discards taken out of stock that were calculated from the KEMA survey data
are reported in Column (5) of Table 2. These percentages were applied to the percentages in
Column (4) to arrive at the annual percentages of discards taken out of stock, as reported in
Column (6).
Inspection of the calculated hazard (removal/failure) rates for each age category in Table C-2
shows that the hazard rate is not constant across categories. This indicated that it was not
warranted to assume that the survival function could be represented using the exponential
distribution, since the hazard rate for an exponential survival function is constant. However, the
Weibull distribution does allow for hazard rates that change over time, and the Weibull-based
hazard function was therefore used as the functional form for calculating the hazard function for
discarded refrigerators.
The discard rates in Column (6) of Table 2 were then used to calculate a survival function for
refrigerators. The power curve fitted to the hazard rate data in Table C-2 was:
Hazard rate = h(t) = 0.00722Age0.8144
The R2 for this fit was 0.70. The parameters from this power curve fit to the hazard rate data
implied the following parametrization of the Weibull function for the hazard function:
Weibull hazard rate function = 0.0040 x 1.8144 x Age0.8144.
The associated survival function is given as:
Appendix C
C-4
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011
Percent surviving at age t = S(t) = exp(-0.0040 x Age1.8144)
This calculated survival function was used to generate the life table shown in Table C-3, which
allows calculation of the remaining useful life for a refrigerator of any given age per usual lifetable methods.
Table C-3. Life Table to Determine RULs for Refrigerators
Age
Column
1
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Appendix C
lx
ndx
Lx
Column Column Column
2
3
4
100,000
397
99,603
99,603
993
98,610
98,610
1,489
97,121
97,121
1,925
95,197
95,197
2,310
92,886
92,886
2,649
90,237
90,237
2,943
87,295
87,295
3,192
84,102
84,102
3,399
80,704
80,704
3,564
77,140
77,140
3,689
73,451
73,451
3,775
69,676
69,676
3,826
65,850
65,850
3,843
62,007
62,007
3,829
58,179
58,179
3,786
54,393
54,393
3,718
50,675
50,675
3,628
47,047
47,047
3,518
43,529
43,529
3,392
40,137
40,137
3,252
36,885
36,885
3,102
33,784
33,784
2,943
30,840
30,840
2,779
28,061
28,061
2,612
25,449
25,449
2,443
23,006
23,006
2,275
20,731
20,731
2,110
18,621
18,621
1,948
16,673
16,673
1,791
14,882
14,882
1,640
13,241
13,241
1,496
11,745
11,745
1,359
10,386
10,386
1,230
9,156
9,156
1,109
8,047
8,047
996
7,051
7,051
891
6,160
Tx
Column
5
1,819,012
1,719,409
1,620,799
1,523,677
1,428,481
1,335,595
1,245,358
1,158,063
1,073,960
993,257
916,117
842,665
772,989
707,139
645,131
586,953
532,560
481,885
434,838
391,309
351,171
314,286
280,503
249,662
221,601
196,152
173,146
152,415
133,795
117,122
102,240
88,999
77,254
66,868
57,711
49,664
42,613
Expected
RUL
Column
6
18.19
17.26
16.44
15.69
15.01
14.38
13.80
13.27
12.77
12.31
11.88
11.47
11.09
10.74
10.40
10.09
9.79
9.51
9.24
8.99
8.75
8.52
8.30
8.10
7.90
7.71
7.53
7.35
7.19
7.02
6.87
6.72
6.58
6.44
6.30
6.17
6.04
C-5
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011
Age
Column
1
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
lx
ndx
Lx
Column Column Column
2
3
4
6,160
795
5,365
5,365
706
4,658
4,658
625
4,033
4,033
552
3,481
3,481
485
2,996
2,996
425
2,571
2,571
371
2,200
2,200
323
1,877
1,877
280
1,596
1,596
242
1,354
1,354
209
1,145
1,145
179
966
966
154
812
812
131
681
681
112
570
570
95
475
475
80
395
395
67
327
327
57
271
271
47
223
223
40
184
184
33
150
150
27
123
123
123
-
Tx
Column
5
36,454
31,089
26,431
22,398
18,916
15,920
13,349
11,149
9,273
7,676
6,322
5,177
4,211
3,399
2,718
2,148
1,673
1,278
951
680
457
274
123
-
Expected
RUL
Column
6
5.92
5.80
5.67
5.55
5.43
5.31
5.19
5.07
4.94
4.81
4.67
4.52
4.36
4.18
3.99
3.77
3.52
3.24
2.90
2.51
2.05
1.49
0.82
For each refrigerator recycled through NV Energy’s program, there is information on the year
the unit was built. Thus, the age can be determined for each unit recycled during 2010. Using this
age, the associated RUL for the unit could be determined from Table C-3. For example, a
refrigerator that was 13 years old when recycled in 2010 would have an expected remaining
useful life (RUL) of 10.74 years. Table C-4 shows the assigned RULs for all refrigerators
recycled in southern Nevada through NV Energy’s program.
Appendix C
C-6
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011
Table C-4. Expected RULs for Refrigerators Recycled in 2010 in Southern Nevada
Year Recycled Refrigerator
Was Built
1950
1952
1954
1955
1956
1957
1958
1959
1960
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
Appendix C
Number of Units
Recycled
1
3
4
3
3
4
2
3
3
2
2
4
11
2
3
5
9
7
6
12
3
10
56
38
48
25
79
111
95
114
125
142
133
158
216
226
291
Age of
Recycled
Unit
60
58
56
55
54
53
52
51
50
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
Expected
RUL
1.49
2.51
2.90
3.24
3.52
3.77
3.99
4.18
4.52
4.67
4.81
4.94
5.07
5.19
5.31
5.43
5.55
5.67
5.80
5.92
6.04
6.17
6.30
6.44
6.58
6.72
6.87
7.02
7.19
7.35
7.53
7.71
7.90
8.10
8.30
8.52
C-7
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011
Year Recycled Refrigerator
Was Built
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Number of Units
Recycled
276
189
224
524
284
166
261
278
656
239
267
204
138
159
97
77
41
22
20
4
Age of
Recycled
Unit
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Expected
RUL
8.75
8.99
9.24
9.51
9.79
10.09
10.40
10.74
11.09
11.47
11.88
12.31
12.77
13.27
13.80
14.38
15.01
15.69
16.44
17.26
Using the data shown in Table C-4, the mean RUL for refrigerators recycled in southern Nevada
is calculated to be 9.76 years.
Similar procedures were applied to calculate mean RULs for freezers recycled in southern
Nevada and for refrigerators and freezers recycled in southern Nevada. The various mean RULs
are shown in Table C-5.
Table C-5. Calculated Mean RULs for Refrigerators and Freezers Recycled
through NV Energy’s Program in Southern and Northern Nevada in 2010
Using Survivor Function Calculated from 2009 RASS Data for SCE
Type of Appliance Recycled
Refrigerators
Freezers
Mean RUL by Service Territory
Southern Nevada
Northern Nevada
9.76 years
8.74 years
10.21 years
9.36 years
The mean RULs shown in Table C-5 were calculated based on a survival function analysis that
used data for households in the service territory of Southern California Edison. To assess the
sensitivity of these results to the calculated survivor function, data from the 2009 RASS for
California for SCE, PG&E, SDG&E and LADWP were combined to develop the survivor
Appendix C
C-8
Second Refrigerator Recycling Program: 2010 – NV Energy, Southern Nevada
M&V Report
May 2011
function used to calculate RULs. Table C-6 shows the calculated mean RULs when the survivor
functions estimated from the combined California RASS data are used.
Table C-6. Calculated Mean RULs for Refrigerators and Freezers Recycled
through NV Energy’s Program in Southern and Northern Nevada in 2010
Using Survivor Function Calculated from Combined 2009 RASS Data
for SCE, PG&E, SDG&E, and LADWP
Type of Appliance Recycled
Refrigerators
Freezers
Mean RUL by Service Territory
Southern Nevada
Northern Nevada
11.93
10.86
11.82
10.86
Tables C-5 and C-6 show that the mean RULs calculated for refrigerators and freezers through
this analysis are longer than eight years. This indicates that using an effective useful life of eight
years for recycled refrigerators and freezers would be a conservative assessment of the remaining
useful life.
Appendix C
C-9