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Weatherization Assistant: What’s New in Versions 8. 4 and 8. 5 Mark Ternes Mike Weatherization Assistant: What’s New in Versions 8. 4 and 8. 5 Mark Ternes Mike Gettings Oak Ridge National Laboratory 2009 National Weatherization Training Conference July 22, 2009 Managed by UT-Battelle for the Department of Energy

Purpose of This Presentation · Discuss MHEA field test and analyses results that led Purpose of This Presentation · Discuss MHEA field test and analyses results that led to important technical changes in Version 8. 4 – – MHEA field validation (overall performance) BESTEST (UA values and space-heating load) RESNET procedures (energy consumption) True-up using the MHEA field validation homes (overall performance) · Summarize potential program impacts from use of the revised MHEA · Identify and discuss other changes that have been made in Version 8. 4 and 8. 5 2 Managed by UT-Battelle for the Department of Energy

MHEA Field Validation Study · Validation performed at DOE request before full implementation of MHEA Field Validation Study · Validation performed at DOE request before full implementation of MHEA · Validation report published November 2007 (ORNL/CON-501) · Findings (86 homes) – MHEA over predicted space -heating energy savings of weatherization measures by ~200% on average per home – MHEA achieved an average realization rate of ~35% (actual savings divided by predicted savings) 3 Managed by UT-Battelle for the Department of Energy

Home Energy Rating System (HERS) Building Energy Simulation Test (BESTEST) · Uses a basic Home Energy Rating System (HERS) Building Energy Simulation Test (BESTEST) · Uses a basic single-family, site-built house that is simplistic enough to be modeled in MHEA · 10 different test configurations of this basic house – – 4 Insulation and infiltration levels Glazing properties and orientation Shading Internal loads Managed by UT-Battelle for the Department of Energy

Comparison of UA Calculations Component Floor – R-11 Floor – R-0 Wall – R-19 Comparison of UA Calculations Component Floor – R-11 Floor – R-0 Wall – R-19 Wall – R-11 Wall – R-0 Ceiling – R-57 Ceiling – R-19 Ceiling – R-11 Windows – DP, wood, argon Windows – SP, metal Doors Infiltration – 0. 67 ACH Infiltration – 1. 5 ACH BESTEST 108. 8 363. 3 43. 8 87. 9 213. 7 25. 9 75. 1 114. 3 81. 0 280. 4 13. 2 118. 2 264. 5 MHEA (final) 100. 2 284. 3 43. 3 97. 2 357. 8 45. 5 81. 2 116. 2 119. 8 251. 1 11. 9 67. 9 170. 1

Conclusions Regarding MHEA’s UA Calculations · Some deviations from BESTEST occur: – NOT because Conclusions Regarding MHEA’s UA Calculations · Some deviations from BESTEST occur: – NOT because MHEA calculations are wrong – But because MHEA accurately reflects mobile home construction or for other explainable reasons · MHEA accurately calculates the UA-values of mobile home envelope components 6 Managed by UT-Battelle for the Department of Energy

Space-Heating Load Analysis · MHEA UA-values made to equal BESTEST values to focus the Space-Heating Load Analysis · MHEA UA-values made to equal BESTEST values to focus the analysis on the load calculation engine · BESTEST criteria are based on the results from three hourly simulation programs – DOE-2 – BLAST – SERI-RES · Loads calculated for a Denver climate · Space-cooling loads not examined 7 Managed by UT-Battelle for the Department of Energy

Comparison of Space-Heating Loads Test configuration L 100 A L 110 A L 120 Comparison of Space-Heating Loads Test configuration L 100 A L 110 A L 120 A L 130 A L 140 A L 155 A L 160 A L 170 A L 200 A Annual space-heating load (MBtu) BESTEST range MHEA 48. 75 to 79. 48 64. 3 71. 88 to 103. 99 86. 9 37. 82 to 64. 30 53. 6 41. 82 to 53. 98 43. 7 43. 24 to 56. 48 50. 1 40. 95 to 71. 33 54. 2 43. 53 to 74. 18 57. 0 48. 78 to 81. 00 63. 7 61. 03 to 92. 40 74. 3 106. 41 to 185. 87 136. 3

Comparison of Change in Loads Test configuration L 100 A L 110 A L Comparison of Change in Loads Test configuration L 100 A L 110 A L 120 A L 130 A L 140 A L 155 A L 160 A L 170 A L 200 A Change in annual space-heating load compared to a base case (MBtu) BESTEST range MHEA 19. 36 to 28. 12 -18. 57 to -7. 67 -27. 5 to -5. 97 -24. 42 to -4. 56 -12. 53 to -3. 02 -1. 54 to 6. 88 -3. 72 to 5. 1 7. 12 to 17. 64 56. 39 to 107. 66 22. 6 -10. 7 -20. 6 -14. 2 -10. 1 2. 8 -0. 6 10. 0 72. 0

Conclusions Regarding MHEA’s Space. Heating Load Calculations · MHEA passes the BESTEST criteria for Conclusions Regarding MHEA’s Space. Heating Load Calculations · MHEA passes the BESTEST criteria for each of the 10 test configurations, usually falling near the midpoint of BESTEST’s allowable range · MHEA accurately calculates the spaceheating load of a mobile home · MHEA’s loads essentially track BLAST and are about 3 -9 MBtu higher than DOE-2 10 Managed by UT-Battelle for the Department of Energy

RESNET Procedures · Tests space-heating energy consumption calculations for various heating systems using the RESNET Procedures · Tests space-heating energy consumption calculations for various heating systems using the BESTEST base case test configuration · Compares energy consumption of one heating system to another – 90% AFUE furnace to a 78% AFUE unit – 9. 85 HSPF heat pump to a 6. 8 HSPF unit – Electric resistance furnace to a 6. 8 HSPF heat pump · RESNET results are based on the results of six hourly simulation programs – – Two DOE-2. 1 tools Two DOE-2. 2 tools Micropas version 6. 5 TRNSYS version 15 11 Managed by UT-Battelle for the Department of Energy

Results and Conclusions Regarding MHEA’s Space-Heating Energy Consumption Calculations Change in space-heating energy consumption Results and Conclusions Regarding MHEA’s Space-Heating Energy Consumption Calculations Change in space-heating energy consumption (%) Heating system comparison 78% to 90% AFUE gas furnace RESNET range MHEA -13. 3% to -11. 6% -13. 3% 6. 8 to 9. 85 HSPF heat pump -29. 0% to -16. 7% -18. 3% 41. 8% to 80. 8% 52. 3% 6. 8 HSPF HP to electric furnace · MHEA accurately calculates the spaceheating energy consumptions of the tested systems 12 Managed by UT-Battelle for the Department of Energy

So. . . . · MHEA found to accurately calculate: – UA-values – Space-heating So. . . . · MHEA found to accurately calculate: – UA-values – Space-heating loads (essentially equivalent to BLAST or DOE-2) – Space-heating energy consumptions · But re-analysis using the MHEA field validation mobile homes showed that: – MHEA still over predicted savings by 168% – MHEA still achieved a realization rate of only 37% 13 Managed by UT-Battelle for the Department of Energy

Modifications to True-Up MHEA Predictions to Field Validation Results · Modeling of field validation Modifications to True-Up MHEA Predictions to Field Validation Results · Modeling of field validation homes in MHEA – Turned off programmable thermostat measure (12% of the homes) – Floor insulation levels of 0 in. changed to 0. 5 in. (14% of the homes) · Engineering modifications to MHEA – Changed MHEA’s internal load assumptions to be more consistent with HERS and NEAT – Reduced MHEA’s infiltration loads by ~25% – Added an R-value of 1 to the ceiling, floor, and walls · Applied a 0. 6 correction factor to MHEA’s energy savings calculations 14 Managed by UT-Battelle for the Department of Energy

Results from True-Up Modifications · MHEA’s over prediction of energy savings reduced to just Results from True-Up Modifications · MHEA’s over prediction of energy savings reduced to just 28% · MHEA’s realization rate increased to 78% · Use of MHEA’s optional billing adjustment feature can further improve MHEA’s accuracy on individual homes – Over prediction of energy savings reduced to 16% – Realization rate increased to 87% 16 Managed by UT-Battelle for the Department of Energy

Simulation of Program Impacts from Use of the Revised MHEA · Compared recommendations from Simulation of Program Impacts from Use of the Revised MHEA · Compared recommendations from the revised MHEA (Version 8. 4) to the original (Version 8. 3) – Frequency that measures are recommended – Average investment levels per home · 18 mobile homes in Ohio – 13 heated by natural gas – 5 electrically heated · Columbus weather (5723 HDD) · State-supplied fuel and installation costs · Included health & safety and repair items 21 Managed by UT-Battelle for the Department of Energy

Program Impact Results and Conclusions · Use of the revised MHEA does NOT eliminate Program Impact Results and Conclusions · Use of the revised MHEA does NOT eliminate the recommendation of insulation measures – – Roof: from 72% of the homes to 61% Floor: from 89% of the homes to 61% Wall: 17% for both versions of MHEA Storm windows: 83% of the homes to 39% · Average investment levels remained high – Average investment per home dropped from $2832 to $2193 – Recommended investment level changed less than $130 in 39% of the homes 22 Managed by UT-Battelle for the Department of Energy

MHEA Steering Committee Comments · MHEA is now more accurate – Estimated energy savings MHEA Steering Committee Comments · MHEA is now more accurate – Estimated energy savings and SIRs are more reasonable · The changes made in the revised MHEA move the recommendations in the right direction – Measures with questionable economics – like storm windows or insulating a roof with a decent amount of insulation in it – are less likely to be recommended · Recommend issuing the revised MHEA once remaining programming issues are resolved 23 Managed by UT-Battelle for the Department of Energy

Conclusions · MHEA’s basic engineering calculations were found to be accurate · Several adjustments Conclusions · MHEA’s basic engineering calculations were found to be accurate · Several adjustments had to be introduced into MHEA to make its energy estimates agree with measured field data · Recommendations appear to be reasonable · Program impacts compared to Version 8. 3 appear to be reasonable and as expected · Final report published December 2008 (ORNL/CON-506) · Version 8. 4 of the Weatherization Assistant with the revised MHEA was released November 14, 2008 24 Managed by UT-Battelle for the Department of Energy