Residential Duct Insulation New Deemed Measure Proposal – A Second Look Regional Technical Forum May 4 th, 2010

At the April RTF Meeting… Look into the ETO’s evaluation numbers in more detail and determine whether/how the RTF should apply them Recommend changing a few assumptions, requirements – 75% of ducts in crawlspace, vs 90%; 150 square foot minimum duct area, vs 250. Recommendation to run model with 50% duct insulated, 50% un-insulated 2

Another Look at ETO’s In-House Evaluation Numbers Savings convert to about 400 kWh/year PTCS Duct Sealing was required, but may not have always occurred Median linear feet: 182 3

Thoughts? Is this Deemable? – Early sunset date with a required evaluation effort? Savings metric? – Per house? Per linear foot? Other? Savings Calculation? – Use 50/50 savings? 4

Residential Duct Insulation New Deemed Measure Proposal Regional Technical Forum April 6 th, 2010

Proposed Deemed Measures Savings and costs are “per house” Insulation of flex duct not allowed Cooling Zone 1 shown. Zones 2 and 3 are very similar (slightly larger savings) 6

Savings Methodology & Inputs SEEM Modeling 3 Site Built Prototypes (1344 ft 2, 2200 ft 2, 2688 ft 2 ) – 1344 and 2200 prototypes: supply ducts in crawl; return in attic – 2688 prototype: basement, so not included in final numbers Fully Weatherized (Package 8) with Sealed (PTCS) Ducts – Attic: R38, Floor: R30, Windows: u-0.30, Walls: R-13, ACH: 0.35 Modeled both electric FAF and Heat Pump – Heat Pump = 8.0 HSPF (HPA3) Used the 5 baseline heat pump control strategies Duct Insulation Options – Flex Duct Replace R-4.2 flex duct with R-8 flex duct – (R-11 flex duct was not analyzed because of high cost) – Hard Duct Uninsulated (3/4” or less) to R-11 R-4.2 (1.5” or less) to R-11 Used “True R-Values”, assuming round ducts & R-2.8/inch – Assumed R-2 for “uninsulated” ducts case 7

“True R-Values of Round Residential Ductwork” Larry Palmiter and Erin Kruse, Ecotope, Inc. ACEEE Summer Study

More Inputs Important Assumption: Savings between Small and Medium prototypes varies by a factor of ~ 2. 9

Intermediate Savings Calculation Results Annual Savings (kWh/year) 10

ETO Impact Evaluation Results Equivalent kWh (assuming 80% gas efficiency): – ranges from 400 to 1050 kWh/year. 11

Measure Cost ETO Data – Based on 522 duct insulation jobs – All started at R-2 or lower While it’s possible to calculate a cost for the R-4.2 to R- 11 case ($372), it’s probably way too low. So, it was assumed to have the same cost as the uninsulated case (same installation cost, same R-11 batt) – Median Cost $535 per job $0.29/linear foot/∆ R-value – Median Job Size: 182 linear feet Note on Savings – this compares well with what was modeled in SEEM (assuming 30% duct area in contact with floor or attic insulation) Bruce Manclark Data – Based on calls to installers – R8 flex duct = $4 - $5 per linear foot includes removal/disposal of old, installation of new – R-11 on hard ducts: $1.50 to $1.65 per square foot of material Material needed is 1.5 times uninsulated duct area 12

Proposed Measure Requirements Measure Definitions – Flex Duct Replacement Existing supply flex duct shall be rated R-4.2 or lower. Replacement flex duct shall be rated R-8 or higher. – Hard Duct: Existing <1.5” thick, install R-11 Existing supply duct insulation shall be 1.5” thick or less. Supply and return ducts in unconditioned spaces shall be insulated to a nominal value of R-11 or higher. – Hard Duct: Uninsulated (existing <3/4” thick), install R-11 Existing supply ducts shall have less than 3/4” of insulation. Supply and return ducts in unconditioned spaces shall be insulated to a nominal value of R-11 or higher. Measure Requirements – Only applies to houses where a significant portion of the supply ducts are located in a vented, unconditioned crawlspace or attic, or in an unconditioned garage. – Significant means: no less than 90% (by area) or 250 square feet, which ever is less. – Ducts shall be sealed for air-leaks to PTCS standards prior to insulating. – Insulation installations shall follow the RTF’s Weatherization Specifications. – Flex duct installations shall follow manufacturer’s instructions. Reporting Requirements – Crawlspace Foundation Area – House Square Footage – Amount of Insulation Installed Length of flex duct Total area of duct insulation – Project Cost Sunset Date – In 2 years, the measure savings will be re-visited by the RTF. 13

How Should Savings be Reported? By House +Simple, can’t get it wrong -The assumed averages may not match what gets reported -What about houses with some insulation already existing? By House Square Footage +An attempt at normalizing -House square footage doesn’t necessarily correspond to duct insulation area (two stories, basements, etc.) -(Partial insulation?) By Foundation Area +Better normalization -More complex; not intuitive; (partial insulation?) By Linear Feet of Duct +Even better normalization -More complex; less intuitive; reporting errors are common -Doesn’t take into account different duct sizes By Duct Area +Good normalization -Difficult to determine and verify; complex The proposal is by House. Whole house, or nothing. Discussion Encouraged, Implementers Should Also Discuss 14

Some More Things to Think About… Do we have adequate confidence to deem these measures? – Modeling assumptions Existing & replacement R-values don’t account for “real world” installations House size and duct location both have a significant impact on the savings results – How should existing insulation levels be verified? Should the measures be designed in a different way? – Higher insulation levels for colder climates? – More/less options for existing insulation levels/types? Should the RTF attempt to deem additional duct-related measures? – Duct Repairs (replacing damaged flex duct) – Duct Re-Design (to increase airflow for heat pumps) 15

Proposed Deemed Measures (again) Savings and costs are “per house” Insulation of flex duct not allowed Cooling Zone 1 shown. Zones 2 and 3 are very similar (slightly larger savings) Next Steps: Thoughts? 16