Residential High Performance Walls

Transcription

1 2016 Title 24 Codes & Standards Enhancement (CASE) Proposal Residential High Performance Walls May 8, 2014 Matt Christie (TRC) Joshua Rasin (TRC)

2 Agenda Code change overview Summary of current code requirements Current practice Methodology for analyses Initial data and findings Proposed code requirements Specific stakeholder requests 2

3 Proposed Code Change Overview Residential High Performance Walls Lower Prescriptive U-factors for exterior residential walls Tighter building envelope Minimize thermal bridging Apply to low-rise residential buildings in all climate zones The anticipated modification will be to the prescriptive requirements Exploring mandatory QII 3

4 Proposed Code Change History 2013 Residential CASE Reports for Advanced Wall Assemblies and Increased Wall Insulation: Showed U-factors <.054 as cost-effective in climate zones 1-5 and 9-16 Proposed more stringent values than those ultimately adopted for 2013 Standards Developed U-factor tables for various wall assemblies, including 2x6 and 24 o.c. Demonstrated feasibility of various insulation combinations to reach lower U-factors Updated U-factors for SIPs and ICFs in compliance software 4

5 Current Code Requirements Effective Code CA 2-10 CA CA 1, Prescriptive 2013 Prescriptive 2013 Compliance Option (Performance) R-13 R-19 R-21 Maximum U-factor: (R-15+4 or R-13+5) SIPs, ICFs, AWF, or other wall assemblies (i.e. 24 o.c. etc.) Note: these climate zones are California specific. 5

6 Current Practice Typical practice 2013 requirements basis: 2x4 studs 16 O.C. + 1 of continuous insulation (R4). This is assumed to be current practice, although 2x6 studs are becoming more common. Trends and current research Increased insulation/lower U-value walls are being used in cold climate zones and in California advanced home programs. High Performance House ET studies (PG&E, SCE) Multiple projects with 2x6 studs R19 R23 cavity insulation: high density fiberglass or spray foam R4 continuous insulation (1 exterior) 6

7 Methodology for Savings Analysis Energy and Demand Impacts CBECC-Res energy simulation Analysis using 2013 TDV (will update with 2016 TDV when available) Prototype Buildings Baseline: Minimally compliant with 2013 Prescriptive Requirements (U: aka 2x4 studs w/ R15 cavity + R4 continuous insulation, no QII) Res: 2,700 SF (2-story) and 2,100 SF (1-story) 55/45 weighting for applicability of prototypes statewide Prototype Walls Garage Interior Window + Door Areas Framing Cavity Area 2,700 sf prototype 2, ,172 1,612 2,100 sf prototype 1, , % 2,700 sf home 45% 2,100 sf home 1, ,774 1,268 7

8 Methodology for Cost Analysis Cost estimates from multiple sources RS Means Usually most costly/conservative estimate Online retailers Added labor costs from RS Means Interviewed experts for additional cost data and assessment of feasibility Includes builders, contractors, manufacturers, distributors and program implementers in California 8

9 Data and Findings For Climate Zones 1-5 and 9-16 (all but the Southern California coast), a U-factor of is cost effective using 2x6@16, R21 + R6 This U-factor can also be met using 2 of higher quality exterior insulation: 2x4 R15+R10, U x6 R19+R8, U QII is cost effective everywhere except 7. 9

10 Cost scenarios 2013 Prescriptive Baseline Incremental IMC /s.f. StudCavity Exterior U-factor Cost wall area Cavity Insulation Type 2x4 R15 R4 (1") High density batt 2x6 R21 R4 (1") $463 $0.26 Loose-fill cellulose or high density batt 2x4 R15 R8 (2") $566 $0.32 High density batt 2x6 R23 R4 (1") $507 $0.29 High density batt or mineral wool 2x6 R19 R6 (1.25") $446 $0.25 Low density fiberglass batt 2x6 R23 R5 (1") $887 $0.50 High density batt or mineral wool 2x6 R21 R6 (1.25") $752 $0.42 Loose-fill cellulose or high density batt 2x4 R15 R10 (2") $862 $0.49 High density batt 2x6 R23 R6 (1.25") $797 $0.45 High density batt or mineral wool These scenarios all assume 16 O.C. framing Increasing spacing from 16 to 24 o.c. can save ~$0.10/sf of wall area based on lumber cost savings optimal wood use 10

11 Cost breakdown Total incremental cost $1,200 $1,050 $900 $750 $600 $450 $300 $150 $0 ($150) Incremental cost breakdown 2x4 baseline: 2x6 baseline: premium for sill flashing vs 2x4 baseline premium for continuous insulation vs 2x4 baseline premium for cavity insulation vs 2x4 baseline premium for framing vs 2x4 baseline premium for sill flashing vs 2x6 baseline premium for continuous insulation vs 2x6 baseline premium for cavity insulation vs 2x6 baseline premium for framing vs 2x6 baseline ($300) R21+R4 U=0.051 R23+R4 U=0.049 R19+R6 U=0.049 R21+R6 U=0.046 R23+R6 U=0.044 R19+R8 U=0.043 R15+R8 U=0.050 R15+R10 U=0.045 R21+R6 U=

12 Cost basis (average installed cost) Product Type R-Value Description $/ft 2 ft 2 /home $/home Concrete Stucco - Stucco, 3 coats, float finish, with mesh, on wood frame, 1" thick $4.89 $6, One-Coat Stucco (RS MEANS) $3.86 $4, Fiberglass, foil faced and unfaced, 3.5" $0.70 $ Blanket, Mineral wool, 3.5" $0.98 $1,244 Batt Insulation 19 Fiberglass kraft faced, foil faced, and unfaced, 6" $ $ Fiberglass unfaced batt insulation, 6" $1.03 $1, Blanket, Mineral wool, 5.5" $1.06 $1,349 4 EPS, and molded bead board $0.83 $1,050 5 XPS, EPS, Polyiso and molded bead board $1.13 $1,429 Rigid Insulation 6 EPS, Polyiso $ $1,300 8 EPS, and molded bead board $1.21 $1, XPS, Polyiso $1.45 $1,834 Spray foam 19 Polyurethane foam, sprayed, 3.5" $ $4,035 Loose fill 21 Poured insulation, cellulose fiber, R3.8 per inch, 6" thick $ $1,143 Gypsum board - Standard and fire resistant $ $938 OSB - 7/16", 1/2", 5/8" $ $2,414 Weather Barrier - Asphalt felt, polyproylene, and polyethylene $ $447-2x4 16"OC $1.01 $1,793 Wood Framing - 2x6 16"OC $ $2,005-2x6 24"OC $0.99 $1,765 Metal Flashing - Sheet Metal Cladding, aluminum, window casing, up to 6 bends,.024" thick $ $571 12

13 Energy savings scenarios Framing Exterior Insulation R4 R6 R8 R8 R10 R6 Cavity Insulation R21 R23 R19 R21 R23 R19 R15 R21 Incremental Cost $463 $507 $446 $752 $797 $723 $566 $933 $563 U-factor $1,081 $1,260 $1,318 $1,493 $1,653 $1,700 $1,144 $1,497 $1,544 2 $815 $946 $988 $1,117 $1,235 $1,275 $844 $1,100 $1,146 3 $595 $691 $725 $823 $908 $945 $630 $820 $850 4 $741 $859 $896 $1,006 $1,110 $1,148 $753 $976 $1,025 5 $589 $683 $710 $801 $881 $905 $605 $787 $821 6 $420 $488 $502 $568 $624 $643 $411 $535 $572 7 $197 $227 $232 $261 $289 $300 $196 $242 $255 8 $477 $552 $559 $630 $692 $698 $441 $573 $626 9 $752 $871 $892 $1,014 $1,115 $1,115 $716 $940 $1, $831 $970 $991 $1,126 $1,243 $1,242 $807 $1,059 $1, $1,479 $1,725 $1,779 $2,018 $2,228 $2,242 $1,475 $1,954 $2, $1,210 $1,412 $1,465 $1,660 $1,827 $1,864 $1,206 $1,588 $1, $1,478 $1,727 $1,782 $2,020 $2,228 $2,248 $1,474 $1,942 $2, $1,405 $1,641 $1,692 $1,917 $2,116 $2,139 $1,406 $1,852 $1, $1,654 $1,960 $2,000 $2,292 $2,486 $2,452 $1,592 $2,225 $2, $1,425 $1,665 $1,742 $1,972 $2,181 $2,227 $1,478 $1,943 $2,032 13

14 Preliminary energy savings, U-factor = x6@16ocR21+R4, U=0.051 $3,000 $2,500 $2,000 $1,500 $1,000 $500 $ NPV of Savings ($) 2016 Incremental Cost (per house) 14

15 Preliminary energy savings, U-factor = x6@16ocR19+R6, U=0.049 $3,000 $2,500 $2,000 $1,500 $1,000 $500 $ NPV of Savings ($) 2016 Incremental Cost (per house) 15

16 Preliminary energy savings, U-factor = x6@16ocR21+R6, U=0.046 $3,000 $2,500 $2,000 $1,500 $1,000 $500 $ NPV of Savings ($) 2016 Incremental Cost (per house) 16

17 Preliminary energy savings, U-factor = x4@16ocR15+R10, U=0.045 $3,000 $2,500 $2,000 $1,500 $1,000 $500 $ NPV of Savings ($) 2016 Incremental Cost (per house) 17

18 Preliminary energy savings, QII $3,000 + QII $2,500 $2,000 $1,500 $1,000 $500 $ NPV of Savings ($) 2016 Incremental Cost (per house) 2013 CBIA estimate for QII QII costs vary, negligible cost up to ~$450/home Includes cost for HERS inspection and increased labor for quality insulation installation 18

19 Preliminary energy savings, QII and QII $4,500 $4,000 $3,500 $3,000 $2,500 $2,000 $1,500 $1,000 $500 $ NPV of Savings ($) 2016 Incremental Cost (per house) 19

20 Proposed Code Requirements and LCC 1-5, 9-16: U i.e. 2x6 R21 + R6 Framing 2x6@16oc 2x6@16 2x4@16 2x6@24 Exterior Insulation R4 R6 R8 R8 R10 R6 Cavity Insulation R21 R23 R19 R21 R23 R19 R15 R21 Incremental Cost $463 $507 $446 $752 $797 $723 $566 $933 $563 U-factor $618 $753 $872 $742 $857 $977 $578 $564 $980 2 $353 $438 $542 $365 $438 $552 $277 $167 $583 3 $133 $184 $279 $71 $112 $222 $64 -$112 $287 4 $278 $351 $451 $254 $314 $425 $186 $43 $462 5 $127 $176 $264 $49 $85 $182 $39 -$145 $ $43 -$19 $57 -$184 -$173 -$81 -$155 -$398 $9 7 -$266 -$280 -$214 -$491 -$508 -$423 -$370 -$691 -$308 8 $15 $45 $113 -$122 -$105 -$25 -$126 -$359 $63 9 $289 $364 $446 $262 $318 $392 $149 $8 $ $368 $463 $545 $374 $447 $519 $240 $127 $ $1,016 $1,217 $1,333 $1,266 $1,432 $1,519 $909 $1,021 $1, $748 $904 $1,019 $908 $1,031 $1,141 $640 $656 $1, $1,016 $1,219 $1,337 $1,268 $1,431 $1,525 $908 $1,010 $1, $942 $1,134 $1,247 $1,165 $1,320 $1,416 $840 $919 $1, $1,192 $1,452 $1,554 $1,540 $1,689 $1,729 $1,025 $1,292 $1, $962 $1,157 $1,296 $1,220 $1,384 $1,504 $911 $1,011 $1,469 20

21 Alternative Compliance Options Strategy SIPs ICFs Advanced Framing Staggered studs Double Wall Increased rigid external insulation Description Pre-fabricated Structurally Insulated Panels. Pre-fabricated Insulated Concrete Forms 2x6 studs at 24 O.C. framing, 2-stud corners, insulated headers, etc., minimizes thermal bridging and allows for greater volume of cavity insulation. Two 2x4 studded walls staggered to minimize thermal bridging and allow for greater volume of cavity insulation. Two 2x4 studded walls allow for greater volume of cavity insulation. Adding >1.25 of external insulation can achieve lower U-factors and reduce the impact of thermal bridging. 21

22 Outstanding Questions What is the highest density (R-value per inch) wall insulation currently in use? Would builders use new window frames that fit 2 of rigid exterior insulation, if available? Are there additional benefits or barriers to the proposed compliance strategies? Which strategy is preferred by builders? Which of the alternative strategies do builders currently use or would consider implementing? 22

23 Questions? Matt Christie Josh Rasin