1

Deemed Savings Input Assumptions for PTCS Duct Sealing in Existing

Manufactured Homes

February 10, 2004

2

Current Assumptions

Assumption Zone 1 Zone 2 Zone 3

Baseline Duct Efficiency,

10% Supply Losses

84% 83% 82%

PTCS Duct Efficiency,

5% Supply Losses

89% 88% 88%

Savings w/FAF & No CAC (kWh/yr)

900 1,317 1,607

3

Basis for Reconsideration

• Pre & Post Duct Blaster Test on nearly 2400 Manufactured Homes

• Data implies that “baseline” duct leakage is higher than assumed

• Revised Duct System Efficiency model (used for PTCS “sliding scale” calculator) specifically addresses manufactured home construction

4

Pre-PTCS Duct Sealing CFM/SF25

0%

2%

4%

6%

8%

10%

12%

14%

0.04 0.12 0.2 0.28 0.36 0.44 0.52 0.6 0.68 0.76 0.84 0.92 1

5

Post-PTCS Duct Sealing CFM/SF25

0%

5%

10%

15%

20%

25%

30%

35%

0.04 0.12 0.2 0.28 0.36 0.44 0.52 0.6 0.68 0.76 0.84 0.92 1

6

Difference Between Pre & Post PTCS Duct Sealing - CFM/SF25

0%

5%

10%

15%

20%

25%

30%

0.04 0.12 0.2 0.28 0.36 0.44 0.52 0.6 0.68 0.76 0.84 0.92 1

Summary Statistics

ALL Homes in CC Data base

N=2386

Square Footage

Pre duct blaster CFM 50 P

Post duct blaster CFM 50 P

Mean 1,174 278 117 Median 1,152 222 90 Std Deviation 356 211 117 Mode 1,344 140 44 25% Percentile 896 142 58 75% Percentile 1,440 347 133

More Summary Statistics

ALL Homes in CC Data base N=2386

Pre CFM @ 25 P

Post CFM @ 25 P

Difference CFM/SF @ 25 P

Mean 177 74 103 Median 141 57 80 Std Deviation 135 74 105 Mode 89 28 - 25% Percentile 90 37 38 75% Percentile 221 84 138

Still More Summary Statistics

ALL Homes in CC Data base N=2386

Pre CFM/SF @ 25 P

Post CFM/SF @ 25 P

Difference CFM/SF @ 25 P

Mean 0.16 0.07 0.09Median 0.12 0.05 0.07Std Deviation 0.13 0.07 0.10Mode 0.09 0.04 0.0025% Percentile 0.08 0.03 0.0375% Percentile 0.20 0.07 0.12

10

Recommendation

• Use “Median” differential value of 80 CFM25 as most representative of distribution of both pre and post-PTCS duct tightness

• Use PTCS “Sliding Scale” deemed savings calculator duct modeling assumptions for manufactured homes to to derive deemed savings

11

Revised Assumptions

Assumption Zone 1 Zone 2 Zone 3

Baseline Duct Efficiency,

12% Supply Losses

81% 78% 76%

PTCS Duct Efficiency,

5% Supply Losses

92% 92% 92%

Site Savings w/FAF & No CAC (kWh/yr)

1,151 2,305 3.071

12

Current vs Revised Credits

Case Zone 1 Zone 2 Zone 3

Existing

Site Savings w/FAF & No CAC (kWh/yr)

900 1,317 1,607

Existing C&RD Credit $303 $456 $581

Revised

Site Savings w/FAF & No CAC (kWh/yr)

1,151 2,305 3.071

Revised C&RD Credit $360 $715 $954