Proposed Changes to Homes and Small

Buildings for Energy Efficiency

Joan Maisonneuve

CHBA-Alberta

A Tale of Two

NECB – complete document• Applies to large buildings > 3 stories

• Published by NRC in fall of 2011

• Not yet adopted by the province

• Concerns with window to wall ratios

• CHBA working with builders on this

Part 9 Changes • Currently out for review by NRC

• Publishing anticipated late 2012

Scope of Part 9 For EE

Housing and small buildings• Includes secondary suites • < 600 m2 and 3 storey in height (dwellings)• Buildings with dwelling units w/common space <

20% of floor area

Building envelopeHVAC

Service water

Early Work by CHBA National

A reasonable step forward not an arbitrary EnerGuide 80

Elimination of window/door to wall ratios

Reduction of insulation at the attic perimeter

Air tightness is prescriptive areas versus blower door testing

Opaque & vertical area RSI trade-off

Three Compliance Paths

Prescriptive path • No specific ENERGUIDE target

• No air leakage target

• No wdw/wall ratios

Trade-off option Performance Path

• Comparison against a “reference house”

• Energy target = annual energy consumption of reference house

• Air change rate of 3.2 or 2.5 or tested

Conventions for Units

Effective RSI values for walls, ceiling and floors• i.e. transmission through framing combined

with insulated areas

U-value for windows and doors• Overall window value by A440.2

Calculation of Thermal Resistance of AssembliesIncludes:

• Studs, joists, lintels, sills, plates (ladders?)

Excludes:• Minor penetrations (pipes, ducts)• Areas not intended to be heated

Need to calculate major structural penetrations • Balcony slabs, beams, columns• Total area of such penetrations is limited to max 2%

of the gross wall area• If an area exceeds 2% it must be taken into account

Continuity of Insulation

To prevent a break in the continuity of the insulation of the building envelope

• Partitions, chimneys, fireplaces, columns beams, flues

Compensate by insulating for a distance of 4X the thickness of the penetrating element, inward and outward

• Also applies where one bldg components meets another

Requirements for Bldg. Envelope RSI

Location by Climatic Zones

Depends on HRV or NO HRV

Climate Zone , Heating Degree Days oC

Zone 4 Zone 5 Zone 6 Zone 7a Zone 7B Zone 8

< 3000 3000 to 3999

4000 to 4999

5000 to 5999

6000 to 6999

> 7000

Lethbridge EdmontonRed DeerCalgary

Grande Prairie

Minimum ASSEMBLY RSIRED = without HRVBlack = with HRV

Assembly Zone 6Lethbridge

Zone 7aEdm, R.D, Calgary

Zone 7BG.P.

Ceilings below attics 8.66/8.66 (R-50) 10.43/8.66 (R-60) 10.43/10.43 (R-60)

Cathedral ceilings and flat roofs

4.75/4.75 (R- 27) 5.07/5.07 (R-30) 5.07/5.07 (R-30)

Walls 3.27/3.16 (R- 18.5) 3.27/3.16 (R-18.5) 4.13/3.27 (R-24)

Floors over unheated spaces

4.75/4.75 ( R-27) 5.07/5.07 (R-30) 5.07/5.07 (R-30)

Rim joists 3.46/ 3.32 (R-20) 3.46/3.32 (R-20) 3.67/3.46 (R-21)

Foundation walls 3.17/3.17 (R-18) 3.57/3.17 (R-20) 3.57/3.17 (R20)

Unheated Floors below frost line

uninsulated uninsulated uninsulated

Examples of Assemblies

Appendix has tables with examples of assembles and the nominal R-value in various zones:

Trade-off path available

Table A-9.36.2.6.

Minimum Residual Thermal Resistance Value for Insulation, Sheathing(1) and

other Materials for Walls Above and Not in Contact with the Ground

Assembly description Required Effective Thermal Resistance RSI in m²•K/W (See Article 9.36.2.6.)

Description of base assembly

Stud Spacing Nominal insulation

between studs

2.93 3.16 3.27 4.13

mm (in.) m²•K/W Minimum required residual nominal thermal resistance (1) (3) (5) (RSI) in m²•K/W

2x6 wood framing 12.7mm gypsum board, vinyl siding, no

strapping

406 (16”) 3.34 (R19) (2) RSI 0.11 (R 0.6) RSI 0.36 (R2) RSI 0.47 (R2.7) RSI 1.33 (R7.5)

3.87 (R22) — RSI 0.14 (R0.8) RSI 0.25 (R1.4) RSI 1.11 (R6.3)

4.23 (R24) — — RSI 0.11 (R 0.6) RSI 0.97 (R5.5)

610 (24”) 3.34 (R19) (2) RSI 0.04 (R 0.2)3

RSI 0.27 (R1.5) RSI 0.38 (R2.2) RSI 1.24 (R7)

3.87 (R22) — RSI 0.02 (R 0.1) RSI 0.13 (R 0.7) RSI 0.99 (R5.6)

4.23 (R24) — — — RSI 0.84 (R4.7)

2x4 wood framing 12.7 mm gypsum board, vinyl siding, no

strapping

406 (16”) 2.11 (R12) RSI 1.01 (R5.7) RSI 1.24 (R7) RSI 1.35 (R7.7) RSI 2.20 (R12.6)

2.46 (R14) RSI 0.85 (R4.9) RSI 1.08 (R6.1) RSI 1.19 (R6.8) RSI 2.05 (R11.7)

610 (24”) 2.11 (R12) RSI 0.95 (R5.4) RSI 1.18 (R6.7) RSI 1.29 (R7.4) RSI 2.15 (R12.2)

2.46 (R14) RSI 0.82 (R4.6) RSI 1.05 (R6) RSI 1.16 (R6.6) RSI 2.02 (R11.5)

Allowable Reduction In Attic

Reduction in required insulation level at perimeter of attics under sloped roofs

• Minimum nominal RSI 3.52 (R20) at exterior of wall • Maximum 1200 mm from interior/ exterior of wall

Minimum height at outside surface of exterior of wall depends on:

• Minimum 1” vent clearance • Roof slope and location of top-bottom chord junction

Issue for scissor trusses?

Foundations

Building Assembly Below or in Contact With the Ground

Heating Degree-Days(HDD) of Building Location, in Celsius Degree-Days

Zone 4 Zone 5 Zone 6 Zone 7a Zone 7b Zone 8

<3000 3000 to 3999

4000 to 4999

5000 to 5999

6000 to 6999 ≥7000

Minimum Effective thermal resistance (RSI) in m²•K/W

Foundation Walls 2.05 3.17 3.17 3.57 3.57 4.17

Unheated Basement Floors

– below frost line uninsulated uninsulated uninsulated uninsulated uninsulated uninsulated

– above frost line 1.96 1.96 1.96 1.96 1.96 1.96

Floors on Permafrost - - - - 4.44 4.44

Heated Basement Floors ) 2.32 2.32 2.32 2.85 2.85 2.85

Structural Slab on grade 1.96 1.96 1.96 3.72 3.72 4.59

Windows & Doors

No prescriptive area limits• U-values for doors and windows of 1.6 or 1.4• OR Energy Rating values of 25 & 29

17% to 22% FDWR used as references in building envelope trade-off option 3

• Used in performance compliance path

Trade-Off Option

Above ground opaque – Above-ground opaque • Decreased insulation in a wall area compensated by

increased insulation in an equal area of ceiling or another wall

• Limits placed on maximum permitted reduction in performance

• i.e. Tall wall areas

Windows – Windows • increased U-value (decreased R-value) of one

window area compensated by decreased U-value (increased R-value) for another equal window area

Air tightness

Prescriptive details

• Materials, properties, joints, penetrations

• NO testing required in prescriptive path

• Testing may be used in the performance path

Assembly Specification

• Qualified Assemblies plus junctions

Air Tightness

Properties specified for materials intended to provide air tightness

Construction details described for joints and junctions in the airtight material

• Service penetrations including chimneys, ducts, vent stacks, wiring and electrical boxes

• Foundations and sill plates, sill plates and rim joists

• Windows/doors/skylights and walls/ceilings

• Interior walls and exterior walls/ceilings

HVAC

Equipment sized to Can/CSA F-280

HVAC Ducts - generally• Sizing to good practice

Ducts outside the plane of insulation• Sealed joints • Insulated to same level as required for above-grade walls

Ducts – under insulated floors over unheated spaces• Sealed• Insulated to wall RSI • Sides can be insulated to compensate for reduction on top &

bottom • Round ducts? At rim joist area?

HVAC

Intakes and Outlets

• Dampers in most cases

Temperature controlled within 1C

Eliminate conflicts with cooling

Zone adjustment capability required

Automatic humidity control required

HVAC Efficiencies

Table of minimum efficiencies• Gas-fired boilers 90% AFUE

• Gas-fired furnaces 92% AFUE

• Gas-fired fireplaces 62.4% FE

• Air conditioners, air cooled 14 or 14.5 SEER

Concern: • Table includes equipment even where there is no

specified minimum efficiency

Ventilation

HRV’s optional• Reduced level of insulation may be installed

in the building envelope

Where used must have:• Sensible heat recovery efficiency of 60%

Service Water

Service water = domestic water heating equipment

• Gas-fired storage tanks EF> 0.62

• Electric Et > 98%

• Gas-fired tankless < 117kW EF > 0.8

Heat traps above water heaters NOT required

Performance Path

No EnerGuide specified

Comparison between “Reference House” and Proposed House

Reference house = prescriptive requirements

Top Issues From Review

Variation in degree-days

Fireplaces as heating appliances

Overlap of insulation to foundation

HRV installation

Tall walls/trade-off

Guidance for plans examiners

Calculating walk-out basements

Costing

Dave

Questions

Additional Information:• www.nationalcodes.nrc.gc.ca• www.chba.ca