Energy Use Study for the Energy $aving Partners of Colorado
Homes Heated with Natural Gas provide by Excel Energy
1998 - 1999 Program Year
Interim Report
Prepared by Russ Shaber
Fuel consumption data for homes weatherized during the 1998 – 1999 program year by the Energy $aving Partners (E$P) was supplied to the Office Of Energy Management and Conservation by Excel Energy. E$P is the network of Weatherization Assistance service providers in Colorado. Over two thousand account numbers (2105) were submitted to Excel Energy for fuel use information for this evaluation. Just under fourteen hundred (1397) individual homes had information that could be used in the evaluation. The remainder had accounts that had been terminated. One hundred and thirty two units were thrown out of the evaluation because of low correlation coefficients, or other assignable reasons (5 units).
This report goes beyond a simple energy use evaluation. Homes in the evaluation were joined to their corresponding data contained in the E$P Database. The database contains information on the measures and the costs that are associated with each of these units. An attempt was made to understand how individual measures perform, and to analyze the costs associated with these measures. This was done in aggregate, by house type and by agency.
The number of jobs used in any analysis is included for reference. A low sample size is usually a poor representation of the total population. The two units from Region 10 are not indicative of their average costs or measures. They cannot be assumed to represent their typical energy savings either. Site built units included in the evaluation are fairly representative of State-wide averages and most agency averages, when compared to the E$P Database. Mobile home unit costs included in the evaluation tended to be somewhat less representative of the entire set of data for that building type.
1998-99 E$P Average Natural Gas Savings // Jobs / Pre Wx / Post Wx / Savings / Percent Saved /
1265 / 968 / 833 / 136 / 13%
Sites / 1066 / 993 / 854 / 139 / 13%
Mobiles / 199 / 825 / 711 / 116 / 12%
Table 1
The Pre and Post Wx, and the Savings values are given in Therms of natural gas.
The Pre, Post and the savings values are less than those seen in the study done on the program by RLW Analytics in 1999. Energy Savings is about 8% lower in the current study. It should be noted that the total sample size is considerably smaller in this study, which could result in some inaccuracies. Attempts were made to keep as many units in this evaluation as reasonable. Homes that had energy use increases, despite significant work being done, were included in the study. Additional criteria for excluding units might result in a higher savings number.
7
1998-99 E$P Energy Use Study
Savings and Costs by Agency
Natural gas therm and percentage savings are listed by Region in Table 2. Therm savings is more significant than percentage savings because it is a direct measure of performance, where percent savings is an indirect measure. The number of jobs for a region reflects the Excel Energy market share, and not necessarily the total number of homes receiving weatherization services.
Average Savings by Agency /Region / Jobs / Pre Wx / Post Wx / Savings / Percent /
E$P98-01 / 32 / 1098 / 921 / 177 / 14%
E$P98-02 / 175 / 894 / 784 / 110 / 12%
E$P98-03 / 32 / 864 / 790 / 75 / 7%
E$P98-04 / 56 / 890 / 767 / 123 / 10%
E$P98-05 / 17 / 839 / 761 / 78 / 10%
E$P98-06 / 216 / 890 / 762 / 128 / 14%
E$P98-07 / 236 / 919 / 765 / 154 / 16%
E$P98-08 / 149 / 1039 / 898 / 141 / 12%
E$P98-09 / 350 / 1074 / 928 / 146 / 12%
E$P98-10 / 2 / 815 / 855 / -40 / -6%
Table 2
Calculated Labor Costs
Savings is one aspect of program efficiency. Cost is another. In attempting to analyze costs by agency or by measure, it is necessary to assign labor costs. Each agency reports the salaries of their field workers and the number of hours they spend at the job site. Reported hours tends to vary widely from Region to Region. An hourly rate for each Region was determined by dividing the total 1998 Field Salary line item by the total Labor Hours. See Table 3. This helps to mitigate discrepancies in reporting bias and methodology. It also allows for a more accurate accounting of job costs.
Labor RateAgency / Field Salaries / Labor Hours / Hourly Rate
E$P98-01 / $216,276.45 / 6649 / $32.53
E$P98-02 / $465,000.00 / 13608 / $34.17
E$P98-03 / $156,704.31 / 3941 / $39.76
E$P98-04 / $214,848.53 / 12094 / $17.76
E$P98-05 / $143,422.42 / 3287 / $43.63
E$P98-06 / $504,979.07 / 13018 / $38.79
E$P98-07 / $419,528.40 / 12078 / $34.73
E$P98-08 / $200,891.55 / 7469 / $26.90
E$P98-09 / $371,921.41 / 14205 / $26.18
E$P98-10 / $280,955.07 / 5467 / $51.39
Table 3
Job Savings to Investment
The Saving to Investment Ratio (SIR) is a common measurement in the Weatherization Assistance Program. Table 4 contains a simplified approach to calculating an SIR for each Region and for all the jobs in the evaluation. This approach was applied to both mobile homes and site built homes. The Job Costs were calculated by adding the sum of materials costs to the product of labor hours multiplied by the labor rate. The twenty year savings was calculated by multiplying therms saved by the current cost per therm by twenty (Savings*.54 *20). The Fuel Escalation Rate, Discount Rate, Life of Measures, and Diminishing Returns were not factored into this analysis. Current Fuel Escalation Rate predictions are either flat or negative. The current Discount Rate is 3.4%. Including the savings for measures that are less than twenty years and factoring in Diminishing Returns would tend to offset the Discount rate. The Simple Job Discount Rate is given here for comparison purposes only. While it does approximate a savings and costs ratio, it is not based on the formula approved by DOE for calculating SIR. Information in italics does not show a strong correlation with costs and measures in the E$P Database.
Simple Saving to Investment RatioSites / Jobs / Job Costs / 20 Yr Savings / Simple Job SIR
E$P98-01 / 30 / $1,075.35 / $2,004.48 / 1.9
E$P98-02 / 149 / $1,411.28 / $1,237.57 / 0.9
E$P98-03 / 26 / $1,036.22 / $754.38 / 0.7
E$P98-04 / 39 / $1,018.52 / $1,633.28 / 1.6
E$P98-05 / 5 / $1,168.93 / $898.56 / 0.8
E$P98-06 / 139 / $1,131.08 / $1,438.56 / 1.3
E$P98-07 / 183 / $1,235.50 / $1,674.76 / 1.4
E$P98-08 / 144 / $949.57 / $1,484.78 / 1.6
E$P98-09 / 350 / $888.18 / $1,576.48 / 1.8
E$P98-10 / 2 / $691.01 / -$432.00 / -0.6
State / 1067 / $1,076.09 / $1,502.55 / 1.4
Mobiles
E$P98-01 / 2 / $797.21 / $469.80 / 0.6
E$P98-02 / 26 / $2,207.15 / $922.97 / 0.4
E$P98-03 / 6 / $1,966.44 / $1,033.24 / 0.5
E$P98-04 / 17 / $1,268.11 / $633.42 / 0.5
E$P98-05 / 12 / $1,382.96 / $821.66 / 0.6
E$P98-06 / 77 / $2,018.45 / $1,287.58 / 0.6
E$P98-07 / 53 / $1,753.74 / $1,605.10 / 0.9
E$P98-08 / 5 / $2,422.69 / $2,494.80 / 1.0
State / 198 / $1,865.63 / $1,254.82 / 0.7
State:
Mobiles and Sites / 1265 / $1,199.04 / $1,463.97 / 1.3
Table 4
Cost per Home
Table 5 is a simple representation of E$P program funds that are embodied in work and materials at the clients home, and those funds that are not. Job Costs are Materials and Labor. Non Job Costs are overhead expenses that support work in the field.
Comparison of Job Costs to Non Job CostsUnit Average / Job Costs / Non Job Costs
E$P98-01 / $2,105.00 / $1,457.00 / $648.00
E$P98-02 / $2,224.00 / $1,575.00 / $649.00
E$P98-03 / $2,143.00 / $1,255.00 / $888.00
E$P98-04 / $2,375.00 / $1,255.00 / $1,120.00
E$P98-05 / $3,085.00 / $1,475.00 / $1,610.00
E$P98-06 / $1,749.00 / $1,298.00 / $451.00
E$P98-07 / $2,348.00 / $1,400.00 / $948.00
E$P98-08 / $2,026.00 / $1,038.00 / $988.00
E$P98-09 / $1,655.00 / $811.00 / $844.00
E$P98-10 / $2,420.00 / $1,390.00 / $1,030.00
State / $2,085.00 / $1,234.00 / $851.00
Table 5
Disaggregated Energy Savings
One of the goals of the Colorado Energy $aving Partners program is to continually improve.
Increasing energy savings and cost-effectiveness is an area where information on the effects of specific measures will be able to help us make better decisions. The information in Table 6 was derived by matching measures reported in the E$P Database to energy savings for each job in the evaluation.
Prescriptive and non-reportable measures were installed at many of these jobs. These types of measures may include duct sealing, water heater insulation, pipe insulation, weather stripping, and air leakage reduction. Homes that received no reportable measures may have had very little of this type of work done, or these measures may have little impact on energy savings.
Table 6 indicates the energy savings for jobs receiving single and multiple measures. Floor measures are typically installed on mobile homes and not on site built home, but Floor was not filtered by house type for this analysis. Perimeter insulation is typically performed on site built homes, and not on mobile homes. A visual check of the data tended to confirm this assumption, but cannot be relied on as completely accurate. Filtering by house type and then by measure will be a feature of the Final Report.
Energy Savings by Reportable MeasureMeasures / Jobs / Savings / Percent
No Reportable Measures / 232 / 13 / 0.7%
Single Measures
Attic / 237 / 143 / 12.5%
Walls / 77 / 113 / 11.7%
Perimeter / 64 / 68 / 6.8%
Floors (Mobile) / 37 / 65 / 7.7%
Storms / 17 / 67 / 7.4%
Two Measures
Attic Wall / 184 / 224 / 20.5%
Attic Perm / 114 / 181 / 18.1%
Attic Floor (Mobile) / 74 / 155 / 17.0%
Wall Perm / 38 / 149 / 15.3%
Wall Floor (Mobile) / 4 / 99 / 8.2%
Three Measures
Attic Wall Perm / 101 / 266 / 25.9%
Attic Wall Floor (Mobile) / 11 / 154 / 15.9%
Attic Floor Storms / 38 / 120 / 12.5%
Table 6
Homes receiving furnace replacements were analyzed for energy savings, and the results are shown in Table 7. Furnace Replacements were also aggregated with other measures. The sample sizes are relatively small for this dataset, and therefore do not have a high degree of reliability. The interaction of Furnace Replacement on the performance of other measures has been assumed to be same for all measures. This Table suggests that may not be the case. Further study on this issue may be warranted. In all cases Furnace Replacement had a substantial impact on energy savings.
Energy Savings for Furnace ReplacementsMeasures / Jobs / Savings / Percent
Furnace Only / 10 / 114 / 14.6%
Furnace and Attic / 20 / 175 / 16.2%
Furnace and Wall / 10 / 227 / 24.2%
Furnace Attic Wall / 18 / 261 / 23.8%
Furnace Attic Floor (Mobile) / 8 / 169 / 18.8%
Furnace and Any Three Measures / 13 / 269 / 28.9%
Table 7
Job Costs and Energy Savings
The RLW Evaluation of the E$P program noted savings by cost. That study noted a lineal relationship between savings and materials cost, with a savings plateau at about $400. This evaluation looks at costs and savings at both ends of the savings spectrum. Table 8 shows costs and savings for Low Need Jobs. A Low Need Job is defined as having no reportable measures and no significant Health and Safety expenditures. Simple savings and a simple Job SIRs were calculated for both Low Need Jobs in Table 8 and High Saving Jobs in Table 9.
Low Need Jobs are significantly less costly to weatherize than High Saving Jobs, but their cost-effectiveness is considerably lower. This does not take into account the significant overhead costs associated with these units. Labor time for Low Need Jobs remains relatively high, despite the reduction in requirements for these homes.
Low Need Jobs Costs and SavingsJobs / Savings / Percent / Hours / Job Cost / 20 Yr Savings / Job SIR
Sites / 210 / 9 / -0.2% / 12 / $420.98 / $98.74 / 0.3
Mobiles / 14 / 20 / 2.2% / 13 / $531.24 / $212.14 / 0.3
Table 8
Table 9 and Table 10 display information on jobs that had higher than average energy savings. They constitute 43% of the evaluation population. High Saving Jobs were defined as having saved 148 therms or more. The RLW Evaluation results showed an average (PRISM) savings of 148 therms for the three year analysis. Despite higher costs, High Saving Jobs are far more cost effective than Low Need Jobs.
High Saving Jobs Costs and SavingsJobs / Savings / Percent / Hours / Job Cost / 20 Yr Savings / Job SIR
Sites / 463 / 292 / 26.5% / 33 / $1,365.63 / $3,157.47 / 2.3
Mobiles / 79 / 257 / 27.5% / 43 / $2,145.16 / $2,773.55 / 1.3
Table 9
Table 10 is a compilation of the characteristics of jobs with high energy savings. They have higher than average pre weatherization energy consumption and they receive more measures.
Characteristics of High Saving JobsMeasures per Home
Jobs / Pre Wx / Post Wx / Savings / All / Insulation
Sites / 463 / 1131 / 839 / 292 / 2.3 / 1.8
Mobiles / 79 / 941 / 684 / 257 / 2.6 / 2.1
Attic / Wall / Perim / Floor / Storm / HS / FurnRepl / WHRepl
Sites / 80.1% / 53.8% / 38.9% / 2.4% / 1.3% / 44.1% / 12.1% / 0.4%
Mobiles / 78.5% / 10.1% / 2.5% / 82.3% / 38.0% / 30.4% / 10.1% / 3.8%
Table 10
Preliminary Recommendations
Eight hundred non-Excel Energy Homes were not included in this evaluation. Fuel consumption data for as many of these homes as possible should be collected and included for analysis in the Final Report.