New Proven (and Planning) UES Proposal: Low-e Storm Windows for

Manufactured Homes

Adam HadleyRegional Technical Forum

January 21, 2016

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Overview

Today, we are seeking RTF approval of a new Proven (Planning for HP applications) UES measure for Low-e Storm Windows in manufactured homes• Note the RTF approved this same measure for site built

applications at its July 2015 meeting (link)

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Measure OverviewMeasure Developers BPA, PNNL, RTFCAT Review Adam Hadley, Mohit-Singh-ChhabraTech Sub-Com Review NoR&E Sub-Com Review NoNotes • This is a new measure for the RTF (for MH’s)

• Low-e coating on storm windows have been commercially available since 2009 (PNNL)• Low-e pyrolytic coating is a hard ceramic coating (long-lasting,

durable)• Available at big-box home improvement stores

• Installations are permanent• Both Interior and Exterior Storm Windows Qualify• Often a DIY project• Field studies by DOE have shown significant savings

See PNNL Video for more details (Link)

From: Cort, K.A. “Low-E Storm Windows: Market Assessment and Pathways to Market Transformation.” PNNL. June 2013.

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Measure Specifications(same as site built specs)

• Storm windows must use glazing materials with an emissivity less than or equal to 0.22 and a solar transmittance greater than 0.55, as listed in the International Glazing Database (IGDB) managed by Lawrence Berkeley National Laboratory and measured in accordance with NFRC 300-14,NFRC 301-14 and NFRC 302-10.

• Storm windows must be of the same opening type as the existing prime window.• Storm window shall be permanently installed.• Storm windows shall be oriented with the low-e coating facing toward the interior of the

house.• For installations with metal framed prime windows the storm window’s frame shall not be in

direct contact with the prime window frame.

Measure Identifiers• Existing Window Type

– Metal Frame, Single-pane– Wood (non-Metal) Frame, Single-pane– Metal Frame, Double-pane

• Heating Zones (1, 2, and 3)• Heating System Type

– Electric FAF– Heat Pump

Energy Savings

• Same methodology as other manufactured home weatherization (and windows) measures– Calibrated SEEM runs

• Reminder: The calibration, or adjustment factors, align SEEM heating energy outputs with measured heating energy use (billing analysis)– For detailed background, see: Dec 2013 (link) and May 2014 (link) Presentations; ACEEE Paper (link)

– Measure interaction accounted for as per guidelines• Reminder: The method involves estimating “total savings” from installing all interacting measures at the same time, and then prorating

each individual measures’ savings to that total– For details, see section 2.3.3.4 of Savings Guidelines (link)

– Savings for Heat Pumps set to same as electric FAF (planning for heat pumps)• Same measure baseline and efficient-case input parameters as for single family Low-e Storm UES

– Assumes 10% reduction in whole house air leakage• Roughly based on known field studies which show 7%, 10%, and 17% average reductions

– U-factors and SHGC’s generated using NFRC window modeling software (documented in PNNL Report)1

– Include an adjustment factor (93/96) in the savings estimate to account for storm windows not used correctly through the year based on: • Evaluation in Chicago found that 3 of 96 storm windows (that were still present and in good condition) were not fully closed in the middle

of winter– Cooling savings are not included

• Field study results were highly variable and sometimes negative• SEEM results for SF were unreliable• Occupant behavior in summer (opening windows) confuses the issue

1Cort, KA; SH Widder, TD Culp. 2015. “Thermal and Optical Properties of Low-E Storm Windows and Panels.” PNNL-24444.

Glazing Frame Type BaselineWith Low-e

StormBaseline With Low-e Storm

Metal 1.09 0.41 0.66 0.52Wood 0.88 0.35 0.61 0.50

Double Metal 0.69 0.33 0.63 0.48

Single

Window Type U-Factor SHGC

Note: Wood Frame = non-metal frame

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Measure Life(same as site built measure life)

• 20 years– PNNL estimate, supported by

• The 20 year warranty provided by the two leading manufacturers

• A follow–up evaluation of 5 homes used in a field study in a low-income neighborhood in Chicago, 10 years after installation 96 of 106 storm windows were present and in good condition.

– For details, see Culp, Thomas D. memo to Katie Cort. “Low-E storm window persistence in Chicago case study homes.” January 27, 2015.

9Measure Cost (2014$’s)

(same as site built measure cost)

• Not a lot of data available for installation costs

Low-e Storm Window Costs Value (2014$'s) SourceMaterial Costs (per sq.ft.) $7.50 PNNL (see memo)Professional Installation Costs (per window) $60 PNNL (Wx installer informal survey)DIY Installation Rate 80% PNNL (via manufacturer interview)DIY Instllation Cost (per window) $30 Assumed as 1/2 professional installAverage window size (sq.ft.) 13.5 Analyst assumption (3 x 4.5)Average installation cost (per sq.ft.) $2.67 CalculatedTotal Installed Cost (per sq.ft.) $10.17 Calculated

Note: Wood Frame = non-metal frame

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Proposed Motion“I _________ move the RTF approve the measure specification,

savings, cost, and measure life for the Residential Low-e Storm Windows for Manufactured Homes UES measures and• Set the status to Active• Set the category to Proven

– Set the category to Planning for heat pump applications• The “Research Strategy for Manufactured Homes Heat Pump

Related Measures” (link) is approved for heat pump applications of low-e storm windows measures

• Set the sunset date to May 2020– Set the sunset date to August 2018 for heat pump

applications”

Additional Information on Low-E Storm Window Measure

SH Widder, PNNL

Effect of Mounting Method for Metal Frame Windows

• ~10% increase in U-Factor if metal storm window is mounted directly on metal prime window

Source: Cort, KA; SH Widder, TD Culp. 2015. “Thermal and Optical Properties of Low-E Storm Windows and Panels.” PNNL-24444.

Assumed U-Factor based on thermally

broken installation

Installation Info for Low-E Storm Windows

• BASC– Exterior:

https://basc.pnnl.gov/resource-guides/low-e-exterior-storm-windows

– Interior: https://basc.pnnl.gov/resource-guides/low-e-permanent-interior-storm-windows

• Manufacturer Websites– e.g. Larson:

http://www.larsondoors.com/storm_windows/how_to_install_instructions/

International Glazing Database (IGDB)• The IGDB is a database of measured optical data for glazing

products. – Maintained/QA’d by LBNL on behalf of DOE for use in NFRC rating of

fenestration products• NFRC-qualified products subject to periodic verification testing and noted with a

(#) symbol in the database

– Manufacturers of glazing products submit data collected from a certified laboratory to LBNL for review and inclusion in the database

• Data collected in accordance with NFRC 300 (solar optical properties), 301 (IR properties), and 302 (reporting).

• Submitted data is subject to review by LBNL and a peer-review by other manufacturers.

– Glazing samples are also retained for later reconfirmation or challenges of the listed properties.

• Major manufacturers of low-e storm windows use glazing with similar optical properties

• Other, smaller manufacturers of low-e storm windows include ProVia, Allied Window, Harvey Building Products, Thermolite Windows– Not sure what type of glazing they use

Optical Properties of Low-E Storm Windows

Manufacturer Typical Products Glazing Emissivity1 Solar Transmittance1

LarsonExterior and interior clear and low-e storm windows and doors

AGC Comfort Select 0.148 0.689

QuantaExterior and interior clear and low-e storm windows

Pilkington Energy Advantage 0.164 0.748

Pilkington Solar-E 0.166 0.419

AGC Comfort Select 0.148 0.689

1 As listed in the IGDB, v.41

Solar Heat Gain• Both low solar heat gain and high solar heat gain

low-e storm windows available– Low solar gain windows have same emissivity, but ~20-

50% lower SHGC

• Low solar heat gain low-e storm windows will impact savings could impact savings by ~50%– Will vary based on house size, climate, prime window

sq.ft. and orientation, low-e window optical properties, etc

Air Leakage• Air leakage is extremely variable

(studies report 0-50% infiltration reduction)

• Not well correlated to savingsbased on field studies

• RESFEN1 modeling suggests that air infiltration may account for approximately 23%of total HVAC energy savings

1RESFEN is a residential energy modeling tool maintained by LBNL to help consumers and builders pick the most energy-efficient and cost-effective window for a given application. See http://windows.lbl.gov/software/resfen/resfen.html

U-Factor Validation• SEEM U-factor assumptions based on NFRC

modeling using WINDOWS/THERM (see PNNL Report)1

– Validated based on testing in LBNL’s MoWiTT thermal chamber test facility based on measured heat flux and correcting for air infiltration2

1Cort, KA; SH Widder, TD Culp. 2015. “Thermal and Optical Properties of Low-E Storm Windows and Panels.” PNNL-24444.2Klems, JH. 2002. Measured Performance of Storm Windows. Lawrence Berkeley National Lab.

Attachment Energy Rating Council (AERC)

• Consortium effort led by Window Covering Manufactures Association (managed by DOE)

• During the next 4 years AERC activities include:– Prioritize product types and performance indices (storm

windows are slated to be first product under evaluation)– Characterize the key material properties of window

attachment products (e.g., transmittance, reflectance, and emissivity)

– Conduct product performance simulations and evaluate procedures to used to rate window attachments

Launched in 2015, an independent rating, certification, labeling and performance verification program for fenestration attachments sponsored by DOE.