Prescriptive Duct Sealing in Manufactured Homes: Proposal for Proven UES

Adam HadleyRegional Technical Forum

August 18, 2015

2

Overview

Today, we are seeking approval of Manufactured Home Prescriptive Duct Sealing as a Proven UES measure• New proposed specification• New estimate of savings• New estimate of cost

3

Measure OverviewMeasure Developers RTF, with help from UCONS and Howdy Reichmuth

CAT Review Adam Hadley

Tech Sub-Com Review No

R&E Sub-Com Review No

Notes • The measure is currently a Planning UES

4 Background: The RTF’s Current Duct Sealing Measures

• Performance Duct Sealing needs a research strategy• Prescriptive Duct Sealing has a “research plan”

– “The recommended design is to perform a billing analysis (pre and post billed energy use and weather) for all measure deliveries in 2014 to calculate average savings as a percent of heating energy use. This percent savings will be applied to a SEEM model using last-measure-in analysis to calculate a UES for this measure.”

Reminder: Today’s topic is MH Prescriptive Duct Sealing only

FAF HP FAF HP FAF HP

SF Dec-14 Dec-15 806 642 1166 1056 1317 1261Uses latest SEEM, calibration, and

Option 3

MH Nov-12 Nov-15 1672 1022 2617 1902 3429 2645 Uses old SEEM, old calibration

SFSet to old SF Performance value

(old SEEM, old calibration)

MHSet to current MH Performance value (average heating system)

Sunset Note on SavingsSpec Type Category Status Approved

1095 1858 2474

1543 2477 3267

Prescriptive Duct Sealing

Performance-based Duct

Sealing

Dec-15

SavingsHZ1 HZ2 HZ3

Aug-13

PlanningUnder

Review

Planning Active

MH Prescriptive Measure SpecificationsThese proposed Prescriptive Duct Sealing Specifications were merged from the following two sources and adapted to the RTF measure specification needs:

– Existing RTF Measure Specification (“BPA Spec”)– Avista and PSE MH Duct Sealing Specifications (per UCONS program)

Proposed Specifications:1. Please note: These specifications are intended as the minimum requirements to achieve, on average, the RTF's

UES estimates. Programs should consider adding requirements to reduce negative impacts on health and safety, to reduce costs, to increase the measure life, and to increase energy savings.

2. Ducts must not have been previously sealed through another utility duct sealing program.3. Appropriate materials and duct sealing methods shall be used.

A. UL-181 listed mastic is an appropriate material to seal non-flexible duct connections. Cloth-backed duct tape shall not be used to seal, secure, or fasten ducts. Where there are large gaps in sheet metal or duct connections, repairs shall be made using sheet metal, sheet metal screws, and/or mastic with mesh-reinforcing tape.

B. For flexible crossover ducts, both the inner and outer lining shall be tightly fastened using a compression strap tightened with a tool designed for that purpose.

4. End caps shall be made of either sheet metal or a UL-181 approved rigid product, and sealed.5. Ducts shall be sealed from the interior at every supply register (boot-to-duct connections , floor-to-boot gaps,

and any other duct connections within an arms reach).6. Plenum connections shall be sealed (plenum-to-furnace connection and plenum-to-trunk duct connection).7. Crossover duct connections shall be sealed (crossover duct takeoff-to-plenum and crossover duct-to-collar

connections).8. Inferior sections of crossover duct, such as rusted, crushed, disconnected, torn, or sections otherwise

ineffective, shall be repaired or replaced. 9. Crossover duct shall be mechanically fastened and supported to avoid disconnection and airflow restrictions.

6

Available Data (!)

7 Available Billing Analysis ResultsMH Duct Sealing Programs Operated by UCONS

• Avista Study• Kolp, Danielle Cote-Schiff, et. al. "Avista 2012-2013 Washington Electric Impact Evaluation Report." May 15,

2014. Cadmus.• Puget Sound Energy Study

• Reichmuth, Howard. "Independent M&V Report Puget Sound Energy Manufactured Home Duct Sealing (MHDS) Program, Final." December 5, 2013. Prepared for Thomas Eckhart UCONS LLC.

• Reichmuth, Howard. "MEMO: Addendum2 to PSE MHDS Analysis." June 20, 2015• Snohomish Study

• Reichmuth, Howard. “Independent M&V Report Snohomish PUD Mobile Home Program.” November 2008. Prepared for Thomas Eckhart UCONS LLC.

• * Snohomish duct sealing measure was performance-based, the others were prescriptive• ** The Snohomish evaluation did not separate duct sealing from the other measures: showerheads,

aerators, water heater temperature adjustment, pipe insulation, and CFL’s)

Study N, Program

Participants

N, Screened Group for Analysis

Duct Sealing Savings

(kwh/yr)

Pre-Electric Heating

Energy Use (kWh/yr)

Savings as % of Pre-Heating

Consumption

Avista 1,621 832 1,303 13,435 9.7%

PSE 6,797 2,329 1,020 7,657 13.3%

SnoPUD* 1,679 572 1,301** not available not available

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Proposed Savings Calculation• Methodology

– Estimate a weighted average savings fraction:

– Multiply this 12.3% savings by average heating energy use.• (That’s it!)

• Where do we get the average heating energy use?– (see next slide…)

MH RBSA• Filtered out houses:

– Without electric heating system

– With gas FAF– Poor VBDD fit– Major confounding load

• Which way to split the measure?– Any HZ, Any Htg. System– By HZ and Htg. System Type– By HZ only– By Htg. System Type only– By HZ and Htg. System Type,

but combine HZ 2 and HZ 3

Heating Zone

Heating System

Electric Heating Energy Use

(kwh/yr)

Off-Grid Heating Energy Use

(kWh/yr)

Sample Size

Any Any 7,725 2,108 148

1 7,883 1,717 77

2 10,224 1,740 23

3 9,420 3,921 7

1 4,984 1,690 33

2 7,096 10,009 4

3 n/a n/a -

1 7,192 1,690 112

2 9,589 3,513 29

3 9,420 3,921 7

E. FAF 8,410 1,792 107

Heat Pump 5,322 3,022 37

1 7,883 1,717 77

2 or 3 10,114 2,036 30

1 4,984 1,690 33

2 or 3 7,096 10,009 4

Electric FAF

Heat Pump

Electric FAF

Heat Pump

Any

Any

Staff RecommendationAlso, set Off-Grid for HP in HZ 2/3 to 2,036 (same as Electric FAF)

10 Justification for Use of % Savings

• PSE Study shows fairly consistent % Savings across Pre-Heating Energy Use.– * Within reasonable sample size range, and– **Within the typical range of Pre-heating energy use we look at in UES estimation methods

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12 NEB’s = RBSA Off-grid heating energy savings * Regional retail electric rate– This is the same thing we did for Wx measures

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Measure Cost (2006$’s)• Proposed: $418

– Per Aug 2015 conversation with Tom Eckhart (Based on UCONS MH duct seal program average cost of $475 over the last 2 years)

• Cost range by about +/- $75 depending on the level of treatment received (crossover duct replacement, mostly) and by the location (in- or out-of-park)

• Previous: $375 – Per Nov 2010 conversation with Bruce Manclark (Based on ECOS MH

duct seal program incentive, which covers the entire cost of the job)

Measure Life• Previous: 18 years. No change proposed.

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15 Highlighted Areas

• Proposed specifications may benefit from detailed review by a subcommittee• Does the RTF agree with the proposed method of arriving at the weighted average

savings percentage of 12.3%?• The data in the PSE and Avista impact evaluations do not lend themselves to

disaggregating the measure by heating zones and heating system types (But is the split reasonable?)– In other words, for example, we don’t know whether applying the 12.3% savings to the heat

pump heating energy use is appropriate• Note: Application of the 12.3% savings to the Electric FAF heating energy use is probably pretty close

considering most MH’s use Electric FAF.• Perhaps heat pumps should remain planning?

– Not recommended, but it’s an option if the RTF is uncomfortable applying the savings to heat pumps

– Similar question about whether there’d be a different percentage savings for the different heating zones

• Off-grid savings estimate might be high– Off-grid savings likely wouldn’t act by the same savings mechanism as weatherization measures

(insulating lowers the overall heating load, whereas duct sealing makes the electric heating system more efficient)

• Setting NEB’s to $0 reduces the B/C Ratio only by a small amount, about 0.5

– But there may still be some off-grid savings through takeback (now that the electric heating system is more efficient, it might get used more)

• Does the RTF agree with the proposed handling of measure interactions?– See next slide

16 Highlighted Area: Measure Interactions• We’ve captured interactions from heat pump conversions with measure

identifiers• What about other measures?

– Cost Effectiveness of MH Weatherization measures:

– The savings presented here do not take into account any additional measure interaction. • Is this appropriate? Does the RTF expect these measures to cause savings estimate to change significantly?

Electrical ResistanceHZ1 HZ2 HZ3

Attic R0-R22 2.0 3.3 4.0Attic R0-R30 0.6 1.6 2.2Attic R11-R30 0.4 1.2 1.5Floor R0-R22 0.6 1.2 1.6Floor R11-R22 0.3 0.6 0.8Infiltration Reduction 0.6 1.2 1.1Single-Cl22 0.8 1.3 1.7Single-Cl30 0.9 1.5 1.9Cl35 - Cl22 0.2 0.3 0.4Cl35 - Cl30 0.4 0.6 0.6Double-Cl22 0.3 0.9 1.4Double-Cl30 0.3 1.0 1.5

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Proposed Motion

“I _________ move the RTF approve the revised savings, cost, and specifications for the Manufactured Home Prescriptive Duct Sealing UES measure and• Change the category from Planning to Proven;• Keep the status as Active; and• Set the sunset date to August 2018.”

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Extra Slides

Savings Guidelines2.3.3.4 Interactions between Measures

In many cases, the savings of one measure depends on whether another measure is present. For example, the savings for residential weatherization measures depend on the efficiency of the heating system, in particular, whether a heat pump is used for space heating. The UES for each measure should account for all significant interactions with any of the other measures that are currently RTF approved. Interaction is significant if the RTF determines that it could change a measure’s savings estimate by more than ± 10%.

To the extent practical, identifiers should be used to account for significant measure interactions. For example, the identifier ‘heating system type’ could be used to account for the interactions between various envelope improvement measures and a heat pump measure. When measure identifiers do not account for all significant interactions, the savings can be estimated using the following steps: 1. Estimate baseline energy use of the measure-affected systems for typical adopters at the time of RTF approval. 2. Estimate efficient-case energy use assuming the delivery of the measure and full adoption of all cost-effective

current RTF approved interactive measures. This is referred to as the full package. To avoid multiple iterations of the analysis to determine the full package, cost effectiveness of the interactive measures may be estimated.

3. Compute full-package savings as the difference between the baseline energy use and efficient-case energy use of the full package.

4. Marginal savings for any measure is defined as the difference between the full-package energy use and the energy use of the full package without that measure. Compute marginal savings of the measure and each measure that interacts with it in the full package.

5. Compute the total marginal savings as the sum of the marginal savings for the measure and the marginal savings for each measure that interacts with it.

6. To estimate the measure’s savings, compute the ratio of full-package savings to total marginal savings and multiply this ratio by the measure’s marginal savings.

Other methods may be used if the RTF determines that they more reliably account for measure interactions.

The methods used to account for measure interaction must be documented in the Summary sheet of the Measure Assessment Workbook.