Assessment of Energy Savings from Proposed Revisions to Oregon Residential Specialty Code

Ben Larson2 November 2010

ben@ecotope.com4056 9th Avenue NE, Seattle, WA 98105(206) 322-3753

Background and GoalsBackground:

New Oregon residential energy code proposal analysis. The OR-BCD has asked the RTF and Ecotope to produce a savings estimate.

Last Meeting: Presented methodology

Goals Today: Present analysis findings &

recommendations Obtain approval of predicted savings 2

Oregon Residential Specialty CodeCode revision goal is to reduce

whole-house energy use by 10% over the 2008 code.

Code covers single family detached and multi-family dwellings 3 stories or less.

3

Modeling Steps Determine representative characteristics of housing

population including: Climates Single Family (SF) and Multifamily (MF) occupancies HVAC systems Prototype buildings

Compile base case and proposed code requirements Calculate annual energy use for the representative

housing population. End uses considered include: Heating, Cooling, Ventilation, Lighting, and DHW

Weight calculation outputs together based on housing population data

4

Review: Housing Characteristics Weightings

5

Climate Single Family

Multi Family

Portland 0.59 0.19Redmond 0.15 0.01Medford 0.06 0.01

State Average 0.79 0.21

System Type Single Family

Multi-family

Gas Furnace 0.26 0.12Gas Furnace with

Cooling0.56

0.2Heat Pump 0.09 0.05

Electric Resistance Zonal

0.090.63

Updated: Prototype Weightings Single Family unchanged from 28 September:

1344ft2 – Single story over crawl space 2688ft2 – Like 1344, but over a conditioned basement 2200ft2 – 1.5 story split level with garage and bonus room (over crawl)

Updated: Multifamily prototype is a single unit in an eight unit townhouse complex. Prototype used in previous OR analysis (at least as early as 1990) 952ft2 conditioned area per unit (stacked units, 4 on bottom, 4 on top) Both slab-on-grade and crawl space modeled

Net result: 51 different house types resulting from combination of climates, prototypes, and heating systems.

SF Prototype

Weight

1344 0.152200 0.752688 0.1

MF Prototype

Weight

952 crwl 0.78952 slab 0.22

6

Oregon Code Proposal Code proposal uses the existing core

prescriptive requirements from 2008 (but does add provision for heat pump aux heat outdoor

temperature lockout) The new code savings come from a

revised set of additional measure tables. The code will require the selection of two measures. The measures are divided into two categories

with one measure being selected from each category. ▪ Envelope Enhancement Measures (6 options)▪ Conservation Measures (7 options) 7

8

1 High efficiency walls & windows: Exterior walls – U-0.047 / R-19+R-5 (sheathing)Windows-U-0.30  

2 High efficiency envelope: Exterior walls – U-0.058 / R-21Flat ceilings – U-0.025 / R-49Framed floors – U-0.025 / R-38Windows – U-0.30Doors- All U-0.20, or Add’l 15% high-efficacy lamps

3 High efficiency ceiling, windows & duct sealing:Flat ceilings – U-0.025 / R-49, and Windows-U-0.30, and Performance tested duct systems

4 High efficiency thermal envelope UA: Proposed UA is 15% lower than the Code UA

5 Building tightness testing, ventilation & duct sealing: A mechanical system providing ventilation rates specified in Table 1101.1(3), or ASHRAE 62.2.Blower door testing to 6.0 air changes per hour.Performance tested duct systems.

6 Ducted HVAC systems within conditioned space

A High efficiency HVAC system: AFUE of 90% gas furnaceHSPF of 8.5 heat pump (SEER 13)

B Ducted HVAC systems within conditioned space

C Ductless heat pump: DHP in primary zone with HSPF 8.5 (resistance heat allowed in secondary zones).PTHP with comparable efficiency ratings (no supplemental zonal heaters installed in the building) and integrated backup resistant heat is allowed in a PTHP.

D High efficiency water heating & lighting: Gas tankless EF of 0.80, and 75% CFLs

E Energy management device & duct sealing: Performance tested duct systems , and 75% CFLs

F Solar photovoltaic: Minimum 1 Watt / ft2 conditioned floor space

G Solar water heating: Minimum of 40 ft2 of gross collector area

Envelope

Enhancement

MeasuresConservation

Measures

Analysis Outputs43 possible combinations of

additional measures (after excluded combinations removed)

2394 independent simulation and calculation runs

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Measure Combinations Summary The savings for each measure is a weighted sum

of all the house types across the state Analysis estimates of measure combinations:

14 achieve 6-9% savings 3 achieve 9-10% savings 26 achieve 10-39%

▪ high savings due to certain DHP measure combinations▪ without DHP, savings is 10-17%

Next slide shows the savings for each measure combination. Solar measures left off the table but are included in the overall analysis.

10

11

Statewide Savings Envelope Measure Conservation Measure*

7.1% Walls & Windows HVAC System Upgrade13.4% Walls & Windows Ducts Inside18.2% Walls & Windows DHP

6.0% Walls & Windows75% CFLs & Demand-Gas Water

Heater6.4% Walls & Windows 75% CFLs & Duct Sealing7.8% Envelope & Doors HVAC System Upgrade14.3% Envelope & Doors Ducts Inside19.1% Envelope & Doors DHP

7.0% Envelope & Doors75% CFLs & Demand-Gas Water

Heater7.3% Envelope & Doors 75% CFLs & Duct Sealing6.7% Envelope & Lights HVAC System Upgrade13.4% Envelope & Lights Ducts Inside19.3% Envelope & Lights DHP

5.6% Envelope & Lights75% CFLs & Demand-Gas Water

Heater6.1% Envelope & Lights 75% CFLs & Duct Sealing11.2% Ceiling, Window & Duct Sealing HVAC System Upgrade11.5% Ceiling, Window & Duct Sealing Ducts Inside

10.8% Ceiling, Window & Duct Sealing75% CFLs & Demand-Gas Water

Heater9.9% UA 15% Reduction HVAC System Upgrade16.2% UA 15% Reduction Ducts Inside39.5% UA 15% Reduction DHP

11.1% UA 15% Reduction75% CFLs & Demand-Gas Water

Heater9.5% UA 15% Reduction 75% CFLs & Duct Sealing

8.2%Bldg Tightness & Duct

Sealing HVAC System Upgrade

8.4%Bldg Tightness & Duct

Sealing Ducts Inside

7.4%Bldg Tightness & Duct

Sealing75% CFLs & Demand-Gas Water

Heater14.7% Ducts Inside HVAC System Upgrade

14.8% Ducts Inside75% CFLs & Demand-Gas Water

Heater8.1% Ducts Inside 75% CFLs & Duct Sealing

*Exc

lude

s S

olar

Mea

sure

s

Sensitivity Analysis In practice, housing market will be built

with an uneven selection of these measure combinations Therefore, the overall savings will be a set of

the measure combinations.▪ Selection likely to be driven by cost and minimum

perturbation to existing practices. Some emerging technologies, however, (DHPs, tankless & heat pump water heaters) may alter market dynamics.

Due to (obvious) lack of data of future market behavior, we conducted a sensitivity analysis examining different possible scenarios of measure combination selections

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Measure Selection Scenarios: Equal – combinations selected with equal

likelihood (not realistic) HVAC – furnace, ducted heat pump, and ductless

heat pumps upgrade options widely selected DHW – tankless gas water heater preferentially

selected Middle– middle of the road scenario Low – lowest (worst case) likely savings scenario

where builders select options that save the least

All scenarios bounded by some constraints such as known population of ducted houses, basements, etc.

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Sensitivity Analysis Outputs

14

ScenarioEqualHVAC DHWMiddl

e Low

Envelope

Enhancemnt Measu

res

1 Walls & Windows 0.14 0.07 0.10 0.02 0.072dEnvelope & Doors 0.14 0.07 0.10 0.11 0.092l Envelope & Lights 0.14 0.07 0.10 0.11 0.09

3Ceiling, Window & Duct Sealing 0.14 0.07 0.10 0.03 0.02

4 UA 15% Reduction 0.14 0.07 0.10 0.03 0.03

5Bldg Tightness & Duct Sealing 0.14 0.40 0.40 0.50 0.60

6 Ducts Inside 0.14 0.25 0.10 0.20 0.10

Conservation Measu

res

A HVAC System Upgrade 0.14 0.75 0.52 0.71 0.70B Ducts Inside 0.14 0.01 0.01 0.01 0.00C DHP 0.14 0.13 0.10 0.08 0.05

D75% CFLs & Demand-Gas DHW 0.14 0.05 0.30 0.18 0.19

E 75% CFLs & Duct Sealing 0.14 0.05 0.06 0.01 0.05F Solar PV 0.14 0.01 0.01 0.01 0.01G Solar Thermal 0.14 0.01 0.01 0.01 0.01

Savings12.0

%10.5

% 9.5% 9.6% 8.8%

Sensitivity Analysis FindingsThe explored scenarios deliver a

savings range from 8.8% to 10.5%. The middle scenario shows savings of 9.6% A savings of at least 9.5% generally

holds for other scenarios and combinations (not shown here)

Savings are still short of 10% target, but there is another source… 15

Additions and Remodels Proposed code changes include provisions for

improving house addition and remodel energy performance. 2008 version additions:

▪ <400ft2 core requirements only▪ >400ft2 core requirements plus one additional measure (like new

construction) Proposed changes for additions:

▪ <200ft2 core requirements only▪ 200-600ft2 core requirements plus one additional measure▪ >600ft2 core requirements plus two additional measures (like

new construction) Remodel changes not modeled but there are

significant changes▪ Windows: U-0.65 U-0.35▪ Doors: R-2 R-5▪ Flat ceilings: R-38 R-49▪ Slab perimeter: R10 R-15▪ Underfloor: ≥2x10 Joist R-21R-30, ≤2x8 Joist R-21R-25

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Contribution of New Additions Share of single family new construction based on

floor area Data from Construction Monitor for Clackamas,

Columbia, Marion, Multnomah, Polk, Tillamook, Washington, and Yamhill Counties in 2009

▪ Additional permit activity not counted in table: remodels (1516), additions with no reported square footage (815), and change of occupancy (617).

There is an extensive set of possible combinations for constructing a code-compliant addition. The savings contribution will be small but likely not entirely insignificant.

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Type Percent nNew Buildings 92% 3016

Additions > 600 ft2

5% 480

Additions 200-600ft2

3% 510

Savings from Additions & Remodels An in-depth analysis not conducted because the

population is small and extremely challenging to characterize

A general analysis suggests an additional 0.2-0.5% savings is possible from the most promising sources. Includes the window upgrade for remodels and the effect

of additions shown in the table below.

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Area Savings Type Savings estimat

e*

Add’l measur

es>200ft2 None 0% 0

200-400ft2 New 3-7% 1400-600ft2 None 0% 1

>600ft2 New 6-15% 2*Based on simplified test case simulations and calculations

Summary Findings New construction from code proposal is

likely to see a reduction in site energy use of 9-10% based on the sensitivity analysis of probable measure selection.

The proposals to improve performance of remodels and additions is likely to provide extra savings (~0.5%).

Decision: The probability the Oregon residential code proposal will realize the 10% target is ? A. Very probable B. Reasonably probable C. Highly improbable

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Backup Slides

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Possible ImprovementsEnvelope Measures 1-3: Window

from U-0.30 to U-0.28 or U-0.25Furnace AFUE from 90 to 92House Infiltration in Envelope

Measure 5 from 6ach50 to 5ach50

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Energy Use Calculations Heating and Cooling with SEEM Ventilation with SEEM and side calculations

Building tightness measure requires mechanical ventilation

Lighting based on LPD and 1.5 hr/day on time DHW use based on average SF and MF

occupancy of 2.5 and 1.8 people per unit respectively Energy of hot water used is ~1150 kWh/yr/person (~22

gal/day) MELs excluded from the analysis per OR BCD

request

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Additional Measure Set 1 1 High efficiency walls & windows:

Exterior walls – U-0.047 / R-19+5 (insulation sheathing) / SIPS, and Windows – Max 15% of conditioned area; or Windows-U-0.30  

2 High efficiency envelope: Exterior walls – U-0.058 / R-21 Intermediate framing, and Vaulted ceilings – U-0.033 / R-30, and Flat ceilings – U-0.025 / R-49, and Framed floors – U-0.025 / R-38, and Windows – U-0.30; and Doors- All doors U-0.20, or Additional 15 percent of permanently installed lighting fixtures as high-efficacy lamps

3 High efficiency ceiling, windows & duct sealing: (Cannot be used with Conservation Measure E) Vaulted ceilings – U-0.033 / R-30, and Flat ceilings – U-0.025 / R-49, and Windows-U-0.30 Windows- U-0.30, and Performance tested duct systems

4 High efficiency thermal envelope UA: Proposed UA is 15% lower than the Code UA when calculated in Table N1104.1(1)

5 Building tightness testing, ventilation & duct sealing: A mechanical exhaust, supply, or combination system providing whole-building ventilation rates specified in Table 1101.1(3), or ASHRAE 62.2, and The dwelling shall be tested with a blower door and found to exhibit no more than:

1. 6.0 air changes per hour, or 2. 5.0 air changes per hour when used with Conservation Measure E, and

Performance tested duct systems   6 Ducted HVAC systems within conditioned space: (Cannot be used with

Conservation Measure B or C)All ducts and air handler are contained within building envelope

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Additional Measure Set 2 A High efficiency HVAC system:

Gas-fired furnace or boiler with minimum AFUE of 90% a, or Air-source heat pump with minimum HSPF of 8.5 or Closed-loop ground source heat pump with minimum COP of 3.0

B Ducted HVAC systems within conditioned space: All ducts and air handler are contained within building envelope

C Ductless heat pump: Replace electric resistance heating in at least the primary zone of dwelling with at least one ductless mini-split heat pump having a minimum HSPF of 8.5. Unit shall not have integrated backup resistance heat, and the unit (or units, if more than one is installed in the dwelling) shall be sized to have capacity to meet the entire dwelling design heat loss rate at outdoor design temperature condition. Conventional electric resistance heating may be provided for any secondary zones in the dwelling. A packaged terminal heat pump (PTHP) with comparable efficiency ratings may be used when no supplemental zonal heaters are installed in the building and integrated backup resistant heat is allowed in a PTHP.

D High efficiency water heating & lighting: Natural gas/propane, on-demand water heating with min EF of 0.80, and A minimum 75 percent of permanently installed lighting fixtures as CFL or linear fluorescent or a min efficacy of 40 lumens per Watt as specified in Section N1107.2

E Energy management device & duct sealing: Whole building energy management device that is capable of monitoring or controlling energy consumption, and Performance tested duct systems, and A minimum 75 percent of permanently installed lighting fixtures as high-efficacy lamps

F Solar photovoltaic: Minimum 1 Watt / ft2 conditioned floor space G Solar water heating: Minimum of 40 ft2 of gross collector area

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Characteristics - Portland

Climate SF / MF Proto HVAC Climate SF / MF Proto HVAC Final WeightPDX sf 1344 gfnc 0.777 0.75 0.15 0.26 0.023PDX sf 1344 gfac 0.777 0.75 0.15 0.56 0.050PDX sf 1344 hp__ 0.777 0.75 0.15 0.09 0.008PDX sf 1344 zonl 0.777 0.75 0.15 0.09 0.007PDX sf 2200 gfnc 0.777 0.75 0.75 0.26 0.114PDX sf 2200 gfac 0.777 0.75 0.75 0.56 0.248PDX sf 2200 hp__ 0.777 0.75 0.75 0.09 0.039PDX sf 2200 zonl 0.777 0.75 0.75 0.09 0.037PDX sf 2688 gfnc 0.777 0.75 0.1 0.26 0.015PDX sf 2688 gfac 0.777 0.75 0.1 0.56 0.033PDX sf 2688 hp__ 0.777 0.75 0.1 0.09 0.005PDX sf 2688 zonl 0.777 0.75 0.1 0.09 0.005PDX mf c952 gfnc 0.777 0.25 0.78 0.12 0.018PDX mf c952 gfac 0.777 0.25 0.78 0.20 0.030PDX mf c952 hp__ 0.777 0.25 0.78 0.05 0.007PDX mf c952 zonl 0.777 0.25 0.78 0.63 0.094PDX mf s952 zonl 0.777 0.25 0.22 1.00 0.042 25

Characteristics - Redmond

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Climate SF / MF Proto HVAC Climate SF / MF Proto HVAC Final WeightRDM sf 1344 gfnc 0.154 0.94 0.15 0.2607 0.006RDM sf 1344 gfac 0.154 0.94 0.15 0.5643 0.012RDM sf 1344 hp__ 0.154 0.94 0.15 0.0897 0.002RDM sf 1344 zonl 0.154 0.94 0.15 0.0853 0.002RDM sf 2200 gfnc 0.154 0.94 0.75 0.2607 0.028RDM sf 2200 gfac 0.154 0.94 0.75 0.5643 0.062RDM sf 2200 hp__ 0.154 0.94 0.75 0.0897 0.010RDM sf 2200 zonl 0.154 0.94 0.75 0.0853 0.009RDM sf 2688 gfnc 0.154 0.94 0.1 0.2607 0.004RDM sf 2688 gfac 0.154 0.94 0.1 0.5643 0.008RDM sf 2688 hp__ 0.154 0.94 0.1 0.0897 0.001RDM sf 2688 zonl 0.154 0.94 0.1 0.0853 0.001RDM mf c952 gfnc 0.154 0.06 0.78 0.12 0.001RDM mf c952 gfac 0.154 0.06 0.78 0.2 0.001RDM mf c952 hp__ 0.154 0.06 0.78 0.05 0.000RDM mf c952 zonl 0.154 0.06 0.78 0.63 0.004RDM mf s952 zonl 0.154 0.06 0.22 1 0.002

Characteristics - Medford

Climate SF / MF Proto HVAC Climate SF / MF Proto HVAC Final WeightMFR sf 1344 gfnc 0.068 0.93 0.15 0.2607 0.002MFR sf 1344 gfac 0.068 0.93 0.15 0.5643 0.005MFR sf 1344 hp__ 0.068 0.93 0.15 0.0897 0.001MFR sf 1344 zonl 0.068 0.93 0.15 0.0853 0.001MFR sf 2200 gfnc 0.068 0.93 0.75 0.2607 0.012MFR sf 2200 gfac 0.068 0.93 0.75 0.5643 0.027MFR sf 2200 hp__ 0.068 0.93 0.75 0.0897 0.004MFR sf 2200 zonl 0.068 0.93 0.75 0.0853 0.004MFR sf 2688 gfnc 0.068 0.93 0.1 0.2607 0.002MFR sf 2688 gfac 0.068 0.93 0.1 0.5643 0.004MFR sf 2688 hp__ 0.068 0.93 0.1 0.0897 0.001MFR sf 2688 zonl 0.068 0.93 0.1 0.0853 0.001MFR mf c952 gfnc 0.068 0.07 0.78 0.12 0.000MFR mf c952 gfac 0.068 0.07 0.78 0.2 0.001MFR mf c952 hp__ 0.068 0.07 0.78 0.05 0.000MFR mf c952 zonl 0.068 0.07 0.78 0.63 0.002MFR mf s952 zonl 0.068 0.07 0.22 1 0.001 27