Manufactured Homes Calibration: Existing and New Homes

Mohit Singh-Chhabra & Josh RushtonRTF Update

March 17, 2015

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Overview

Today we are presenting to the RTF:• Update the RTF on subcommittee directions

for existing construction MH• Guidance on CAT proposal for next steps on

new construction MH

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Existing Homes: Background

• Three “Oregon trail” modifications to pure-physics savings estimates:– Calibration Phase I: Align SEEM output with billing data for

RBSA homes with "clean" heating energy data (clean = good VBDD fit and no evidence of off-grid heat)– Calibration Phase II: Account for nonelectric fuel types (gas and

"wood") and poor VBDD fits– Long-term interaction Option 3: Account for interactions with

measures likely to be installed later

• End result: Lower savings than we’re used to seeing• RTF direction: Staff should benchmark Oregon trail

estimates against actual program data

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Existing Homes: Proposed Path(s)

Plan two investigations to test “Oregon trail” estimation procedure:• Savings comparison: Compare bottom-line

“Oregon trail” savings estimates to actual program/billing data – Similar to what we did for SF with ETO data

• Phase I curve comparison: Compare RBSA-based consumption calibration curve to pre-/post- program data– New, explained in this presentation

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Existing MH: Savings Comparison

Compare “Oregon trail” savings to verified program savings (similar to SF savings estimate validation)

• Only trying to test “right-on-average” – Expect to test broad measure groups– No finer-grained tests (e.g., windows / walls /… / ducts)

• Idaho Power 2011-2 program data– 140 MHs (≈105 with 1+ yrs. pre-bills and 1+ yrs. post-bills)– Includes detailed audit data (pre/post shell & equipment specs, blower

door results, …)

• Supplemental Sources: – EWEB evaluation report ~1998– Evaluation reports form CO and the Midwest.

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Existing Homes: Savings Comparison (Contd.)

Idaho Power audit data includes MH HVAC and weatherization measure specs. Enables us to…• Assign “Oregon Trail” savings to program

measures. How do these compare to VBDD-based estimates?

• Check what measures are being implemented. How do Wx’d homes compare to our full measure package assumptions

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Existing Homes: Phase I Curve Comparison

Focus on single (critical) step in “Oregon Trail” Phase I adjustments based on observed trend in differences SEEM.69 – VBDD.kWh • Trend currently based on observational cross-section

of regional homes (RBSA)• Propose to use ID Power data to calculate VBDD and

SEEM.69 for pre-/post- sample • Is existing trend consistent with pre-/post- sample? • Side note: Need to standardize SEEM.69 same as before.

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Existing Homes: Phase I Curve Comparison

Starting point: Add new observations to this graph• Use same filters as

before• Analysis to depend on

what we see • Is the existing trend

consistent with program data?

Remember this?

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New Construction: Background

• Staff received feedback from the RTF that MH New Construction calibration requires dedicated analysis – Don’t just extrapolate existing construction

calibration to new construction values

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New Construction: Staff Proposal Overview

Scope and direction of analysis constrained by data available• Audit and billing data available for a limited number of

homes

• CAT will use this data to verify Phase 1 calibration for new construction

• This process may yield results which are uncertain and require RTF judgment– If results aren’t usable an alternate methodology may suffice

• Staff asking the RTF for head nod on proposed path forward– (explanation next…)

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New Construction: DataAvailable data:• NEEM MH billing and audit data analysis (2006)– 89 homes in final sample across all 4 states– Billing data studied for 78 homes– Raw data sets may not be available– Analysis of building components: Mean values and

distribution of some relevant building properties (Similar to RBSA report)

• New Construction Baseline (Super Good Cents NEEA report (2001-02)) MH field audit data– 101 homes with field audit data; no billing analysis– Not usable without billing data

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New Construction: Data SummarySpecification Data Type Specificity Level Availability

NEEM Specification

Audit Data Building component (window, ceiling, floor, wall, duct)

Regional specs

Available

HVAC system propertiesInfiltration Duct tightness

Climate zone means

Report available

Billing Data VBDD heating energy consumption

Climate zone means

Report available

New Construction Baseline

Audit Data Building component (window, ceiling, floor, wall, duct)

Regional specs

Available

HVAC system propertiesInfiltration Duct tightness

Climate zone means

Report available

Billing Data TBD TBD Possible if billing data is made available

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New Construction: Phase I Comparison

Understand difference in heating energy consumption estimates between SEEM.69 and VBDD analysis• SEEM.69:

– Existing reports give us an estimate of average home HVAC properties and tightness

– The minimum construction specs for Ecorated, ENERGY STAR and Baseline NC homes are known• Need to estimate as built U-values from specs• Use standardized calibration inputs for non-spec fields

• VBDD:– NEEM report provides us with a VBDD estimate of average heating

energy use

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New Construction: Note on Phase I Curve Comparison

Nothing compares, nothing compares… to pre-post

• NC points should fall somewhere in this region

• Would not be able to reproduce phase 1 filters for this.

• Only meaningful if SEEM input conventions consistent across types…– NC vs. RBSA points– Baseline NC vs. NEEM, etc. – Lots of assumptions here

New Construction: Alternate Option

• Estimate savings for new construction measures using billing analysis of existing participants– Compare average measure (ENERGY STAR/Ecorated etc.)

kWh to applicable average new construction MH kWh • Apt for testing average bottom-line savings only

• Call for data: can data to conduct this analysis be made available?– Analysis would require billing data for new construction

MH (baseline, and efficient)– CAT would conduct the billing analysis (is this an

appropriate use of CAT time?)

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New Construction: Proposed Path Forward

• CAT will proceed with the Phase 1 verification for new construction calibration and report back to the RTF.– CAT will explore the alternate option if the Phase 1

verification does not provide usable results

• Does the RTF agree with this proposed path forward?