Bronwyn Barry

Designing & SelectingWindows & Doors for Passive House

Overview:

• Basic Concepts & Anatomy• The evolution of PH windows• Basic PHPP inputs• Optimizing your design for PHPP• Shading (your new best friend)• Comfort Index (Does triple pane actually make sense?)• Cost/Benefit Analysis (can your windows pay for themselves?)• Carbon Footprint

Why windows matter…Back to basics:

Windows (& glass doors) both HEAT and COOL your building

Window Fundamentals & Anatomy:

FrameSashSpacer BarGlazing

SHGCVT

U-factor

Scanned from: Residential Windows by John Carmody et al

U-FACTOR and why it matters

Scanned from: Residential Windows by John Carmody et al

0.690.30.790.510.730.610.43VT

0.520.20.540.30.430.350.18SHGC

97.153.443.573.573.22R-Value

0.110.140.20.290.280.280.31U-Value

Triple -pane Low E Argon

filled

Xenon Dual Pane, 3 High

SHG filmsLow E Argon

filledLow E II

Argon filledLow E 4Insulated Low E II

Low E 363 Argon filled

Glazing

Insulated Fiberglass clad

1125 Series Insulted Fiberglass

Westfalenseries, all wood

Ultrex clad wood casement

Casement/Awning Vinyl-clad

All wood Poly & Rectangles

Primed, push-out casementSeries

ENERsign*

Serious Mat'rlsSorpetaler*

Marvin UltrexAndersenMarvinJeld-WenValue

Performance Rating Values Comparison (Source: Manufacturer’s websites, based on NFRC

testing. All numbers for 2040 casement windows. * Based on ASTM & Passive House Institute testing info. NFRC ratings for the two German windows currently in progress.)

Performance comparison

Source: Straube, John; Can Highly Glazed Building Facades Be Green?, Building Science Insights, BSI-006, www.buildingscience.com, September, 2008.

How windows affect your walls

Darwinian theory for windows…

Source: ARCHnews Green Column, June 2009. Dan Johnson, danjoh99@gmail.com

‘Basic’ PHPP inputs…

5.410.190.540Your glazing name here1

hr.ft2.F/BT

U

BTU/hr.ft2.

F

Rcog-

Value

Ucog-

ValueSHGCGlazing

Ass

emb

ly

No.

Type

2.8804.8104.7504.7504.7504.7505.000.20Your window name here1

hr.ft2F/BTU.i

n

hr.ft2F/BTU.i

ninininin

hr.ft2.F/BT

U

BTU/hr.ft2.

F

ΨΨΨΨInstallationΨΨΨΨSpacerWidth -

Above

Width -

Below

Width -

Right

Width -

LeftFrameFrameFrame

Ass

emb

ly

No.

Thermal

Bridge

Thermal

Bridge

Frame Dimensi

onsRf-ValueUf-ValueType

Source:

THIS TABLE WAS COPIED FROM A LICENSED COPY OF THE PASSIVE HOUSE PLANNING PACKAGE. Inserted information

should be based on values generated by a third party certifier.

Good, Passive Solar basics…

• Large south-facing windows

• Fewer operable units with less mullions

• NO muntin bars

• Stacked windows on first and second stories

• NO sliders or single- & double-hung windows

Basics (cont.)

Don’t mind the threshold…

• Learn to LOVEthe step-over threshold!

Basics (cont.)

• Exterior SHADING!

Basics (cont.)

• Local Exterior SHADING

WA Design, Berkeley, CA

Where windows lose heat…

Source: Analysis of Heat Loss Reduction through window edges by E. isevieius, V. Staponkus, & A. Jurelionis; Kaunas University of Technology, Lithuania. 2005

The RAINBOW analysis…

Window Cost Benefit Analysis

0

10

20

30

40

50

60

Exist

ing

Av. R

3.4

wind

owSo

rpet

aler

SM 9

25Th

erm

oT

SM 7

25EN

ERsig

n

Window Brand

Window 5 R-value

Heat Dem # (kBTU/ft2yr)

Price $K

Delta HD

The meat of the matter!

Source: Compiled by author from data input into the PHPP for a project in Larkspur, Marin.

*** 11 lbs of CO2 saved for each Therm saved

** Assuming $0.13 per kBTU/ft2yr (1 Therm = 100,000 BTUs = $1.30 @ 2,200sf =$286.00)

Why payback analysis is weak:

Window Payback Analysis

0.020.040.060.080.0

Exis

ting

Av. R

3.4

win

dow

Sorp

eta

ler

SM

925

Therm

oT

SM

725

EN

ER

sig

n

Window Brands

$K Saving/a**

$K for 30yrs

Yrs to paybk

30 yr CO2reduction (lbs) ***

Source: Compiled by author from data input into the PHPP for a project in Larkspur, Marin.

But the ‘Comfort’ factor is strong!

Image source: Stefan Carpentier, Berkeley, CA 2009

Project located in Berkeley, CA

The case for triple pane:

Data Source: Dariush Arasteh– LBNL, private email, 2009.

Map Source: http://resourcecenter.pnl.gov/cocoon/morf/ResourceCenter/dbimages/full/973.jpg

11.110.090.53-4-20Zone 7

10.000.10.65-15Zone 6

8.330.120.714-10Zone 5

7.140.140.8423-5Zone 4

5.560.181.05320Zone 3

2.700.372.15010Zone 2

max. R

W(hr.ft2.°

F/BTU)

max. U

W(BTU/hr.ft2.°F)

max. UW (W/m

2-C)

Min. Outdoor Temp (F)

Min. Outdoor

Temp (C)

Approx. US

Climate Zone

35,000.00126.00700.00Heavy TruckBend, OR to Oakland, CA Jeld-Wen/Pozzi

123,950.00446.222,479.00Heavy TruckWarroad, MN to Oakland, CAMarvin

69,400.16131.778,994.00TOTAL:

65,764.16123.098,792.00PS-Type Containter shipRotterdam, NE to Oakland, CA

3,636.008.69202.00Rail- ElectricDortmund, GE to Rotterdam, NESorpetaler & Pazen

CO2 (g/tkm)*Energy (kWh/tkm)*Distance (km)Transport:Location:Manufacturer:

* Sourced from:www.maerskline.com/globalimage/?path=/about_us/table_of_comparisonEnergy Use & Emissions Calculations

The case for imports…

Did I mention Exterior Shading?

Quantum Builders

For Sustainable Living, Inc.

1454 B 4th Street

Berkeley, CA 94110

Tel: 510.559.3488

E: info@quantumbuilder.com

Thank you!