1

Advanced Blower Door Techniques

North Carolina Energy Star Conference Friday November 16, 2007

2

• Is that unconditioned attic connected to the conditioned basement?

Is that nasty crawl space inside or outside the house?

Is that air blasting through the register a leak to the outside or a disconnected duct in the basement?

Learn how to perform the pressure measurements, and more importantly, how to interpret them and understand the implications for air sealing or indoor air quality.

3

Objectives• Learn to use your blower door more effectively

and to improve your air sealing work• Find out how to use pressure diagnostics to

locate thermal bypasses and building connections

• Discover multiple ways of determining air sealing potential, from using basic charts to using computer software and handheld calculators

4

Use Your Blower Door to do more

– Where the air barrier (PRESSURE BOUNDARY) is so we can determine where to air seal

– If the Pressure Boundary and insulation (THERMAL BOUNDARY) line up

– Are zones with poor air quality such as Garages connected to the indoors

– Is warm moist air getting into the cold Attic

5

Zone Testing

• “Pressure Diagnostics” = Zone Testing

• What are Zones?• Spaces that might be better connected to

Inside or Outside

6

ZONE TYPEScan you tell what determines type?

Interior WallAttached Porch

Porch CeilingCrawlspace

SoffitsGarage

Floor Cavity b/w Floors Basement

CantileversAttic

Secondary ZonesPrimary Zones

7

Zone Types• Primary Zones

– Are zones that have an opening in one of the surfaces• House to Zone or Zone to Outside• This is an advantage for testing

• Secondary Zones– Do not have an access in either surface

• Only Direct Pressure measurements can be taken

8

Levels of Zone Testing

• Level 1 – Direct Pressure Measurement (Review)

• Level 2 – Charts and Graphs (Walk away able to do this )

• Level 3 – ZPD Calculators (Will do some examples)

9

Level 1 Pressure Only

• Is the zone more indoors or more outdoors?

• Do Pressure and Thermal Boundaries line up?

10

• The Pressure Boundary and Thermal Boundarymust be together and continuous.

11

• If the boundaries are misaligned or If there are holes,voids or gaps this will make the building difficult to heat and cool.

12

Outside Zones and Inside Zones Measured with Reference to House

We want Zones Outside the House(Unheated Areas) to be closer to 50

We want Zones Inside the House(Heated Areas) be closer to 0

13

Examples of Outside & Inside Zones

Outside Zones(Unheated)

Attics

Garage

Porches

Crawlspace

Basement

Inside Zones(Heated)

Interior Walls

Floors Between Stories

Crawlspace

Basement

14

WRT With Reference To• Zone WRT House = 40PA• Zone WRT Outside = ___PA

• Zone WRT House = 15PA• Zone WRT Outside = ___PA

• Zone WRT House = 25PA• Zone WRT Outside _______PA

15

Let’s Do Some Level 1!

16

Kneewall Attic

Unsealed/Uninsulated

17

Interconnection• Depressurize house to 50 Pa

• Measure pressure to one zone

• Open a door to the other zone, readjust blower door to read 50 again

• If the zones are connected, the pressure in the first zone will change, If not, it won’t

18

Pressures and LeakageAttic Zonal Reading of 25paMeans hole between Attic and House is Same size as Hole Between Attic and Outdoors

19

Pressures and LeakageAttic Zonal Reading of 48paMeans hole between Attic and House is 1/8th size of Hole Between Attic and Outdoors

20

Ratios of Pressures to LeakageZone Pressures Relative Size of Leaks

Zone-House Zone-Out Zone-House Zone-Out

12 38 2 1 25 25 1 1 37 13 ½ 1 41 9 1/3 1 45 5 ¼ 1 48 2 1/8 1 49 1 1/13 1

21

Level 2 Charts and Graphs

– Zone with an opening

– Can calculate square inches leakage of both barriers

– Can calculate the leakage through the zone (available CFM50 reduction) Total Path Leakage

22

Total Path Leakage

• The CFM50 that describes how much air will go through the two barriers

• Always less than the tightest barrier

• Identifies potential for reduction in house CFM50

23

Add a Hole

• Depressurize house to 50 Pa, measure house-zone and zone-out

• Make a hole in one of the barriers• Adjust fan to keep 50 Pa, measure pressures• Use Chart or software to get CFM50 of either

barrier

24

Open a Door (Flow Method)• Depressurize house to 50 Pa, measure house

CFM50, house-zone and/or zone-out

• Open a door with highest pressure difference across it (tightest air barrier)

• Measure new house CFM50– Verify house-zone is near 0 and or zone-out 50

25

New Charts for In-Field

• Garage Chart – You can always open a DOOR H/G or G/O

(makes this easier)

• Attic Chart– You can only open the hatch that is there (a bit

more tricky)

26

Let’s Do Some Level 2!

27

Give the Charts a Try! (Hand them out!)

• Attached garages– Quick– Easy– Important

• Attics– Sometimes Quick and Easy– Also Important

28

Level 3 Software

– More Detailed calculations using Software or Handheld Calculator

– Test Can be automated with laptop computerand equipment

29

Remeasure When You Think You’re Done

• Outside zones (attic, garage) should be much closer to 50 than when you started

• Inside zones (interior walls, chases, ducts) should be much closer to zero than when you started

• Zones that haven’t changed much in the right direction are opportunities for further improvement

30

Limitations/Cautions

• Don’t attribute much meaning to measurements between 47 & 50– Small errors in measuring may generate large

errors in the result– Don’t assume attic is OK because pressure is 48– Can seal zone-exterior (attic vents) to get

numbers into a better range– Read small pressure

31

Limitations/Cautions

• Re-check unusual measurements– “If a number is unbelievable, don’t believe it!”– Disconnected, misplaced or pinched hoses– Unknown fans– Mis-read gauges

• Its best to be able to get 50 Pascal before and after adding a hole

• Zone Connections can give exaggerated numbers in doing advanced on several zones, especially kneewalls

32

Improving Accuracy• Take Baseline Measurements• Measure pressures directly; don’t subtract• Try to measure the smallest pressure

difference carefully• Do it again• For add-a-hole, try to add the hole to the

barrier with the largest pressure difference

33

The End

34

35

36

Are the zones where they are supposed to be??

If not we need to seal holes between inside and outside.

By sealing the holes we stop Air Leakage by making a PRESSURE BOUNDARY

Pressure Boundary (Air Block between Inside and Outside)

39

Kitchen Soffit and Base Cabinetwere open to attic

40

Soffit Open to Attic

41

Kneewall Attic

Insulated/Air Sealed

Heated

Area

42

Kneewall Attic

Insulated/Air Sealed

Unheated

Area

43

44

45

Addition attic is open to Floor System between 1st

and 2nd Floors

(Can Look all the way through to Porch)

Unsheathed Kneewall where addition attic meets 2nd story

46

Porch is Open to Upstairs and DownstairsExterior Walls

Porch is open to Floor System between 1st and 2nd

Floors

(Can Look all the way through to Attic above single story)

47

48

Test Key AreasAttics, Side attics, Porch roofsGarages,Basements, CrawlspacesChases (plumb, elec, duct, chimney)Plumbing Access, Duct Location, Soffits

Keep It SimpleRecord basic pressure measurementsExplain bad pressure readings (ex 10 attic)Should take very little time (Bdoor is all ready up)

49

Kneewall Attic

Unsealed/Uninsulated

50

51

Kneewall Attic

Air Sealed/Uninsulated

52

Kneewall Attic

Air Sealed/Insulated

53

Snow melting because of bypasses in attic kneewall

54

Interconnection• Depressurize house to 50 Pa

• Measure pressure to one zone

• Open a door to the other zone, readjust blower door to read 50 again

• If the zones are connected, the pressure in the first zone will change, If not, it won’t

55

Ratios of Pressures to LeakageZone Pressures Relative Size of Leaks

Z o n e -H o u se Z o n e -O u t Z o n e -H o u se Z o n e -O u t

1 2 3 8 2 1 2 5 2 5 1 1 3 7 1 3 ½ 1 4 1 9 1 /3 1 4 5 5 ¼ 1 4 8 2 1 /8 1 4 9 1 1 /1 3 1

Bypasses

Ceiling Soffit

GableRoof

Attic Zone – Leakage paths and Surfaces

57

ATTICS

• In Mild to Southern Climates (e.g. No Ice Damns) Direct Pressure is sufficient.

• Look at venting to help guide you. – 48PA WRT House and not a lot of venting = good,

but if 48 and lot of venting still should check– 15PA = there are some major holes that need to be

dealt with

58Garage Wall to House

Ceiling

Exterior Garage Walls

Attached Garage Zone

59

Garage

• Advanced Zonal Pressure Diagnostics are recommended – Open Door Method (Manual or with TI-86)– Hybrid Method (with ZPD Utility, PC, PDA,TI-86)

• Ideal to get below 20sq inches of Leakage between Garage and House

60

Basic Procedure

• Measure pressure between the house and a zone, with the house depressurized to 50 Pa– Can close attic vents to get better numbers– Make sure to take baseline pressures– Is this zone in or out? A little or a lot?

• Quantify the leakage– Add a hole– Open a door– Estimate venting

61

Add a Hole

• Depressurize house to 50 Pa, measure house-zone and zone-out

• Make a hole in one of the barriers• Adjust fan to keep 50 Pa, measure pressures• Use chart or software (TI-86) WX Ware) to get

CFM50 of either barrier

62

Take initial direct pressure Reading

Follow up to Line 1 and over to left to find target Pressure

63

Measure Size of Hole made in Square Inches

Open hole to zone enough to reach target pressure

while keeping Blower Door at 50PA

64

Available CFM Reduction

Take initial direct pressure Reading

Follow up to Line 2 and over to right

Sq” size of Hole times Multiplier = available CFM50 Reduction

65

Open a Door• Depressurize house to 50 Pa, measure house

CFM50, house-zone and/or zone-out

• Open a door with highest pressure difference across it (tightest air barrier)

• Measure new house CFM50– Verify house-zone is near 0 and or zone-out 50

66

1

Saturn Resource Management

1

67

68

Estimate Roof Venting

• With house at 50 Pa, measure house-zone and zone-out

• Estimate net free area of roof venting by visual inspection

• Use chart or software to get house-zone CFM50

• Usually the least accurate method, because difficult to estimate net free area

70

Add a Hole, Low-Tech Version

• With house at 50, measure house-zone• Open a hole (attic hatch) just big enough to cut

the house-zone pressure in half– Keep house at 50

• The hole you added is roughly equal to the existing leakage

71

Remeasure When You Think You’re Done

• Outside zones (attic, garage) should be much closer to 50 than when you started

• Inside zones (interior walls, chases, ducts) should be much closer to zero than when you started

• Zones that haven’t changed much in the right direction are opportunities for further improvement

72

Limitations/Cautions

• Don’t attribute much meaning to measurements between 47 & 50– Small errors in measuring may generate large

errors in the result– Don’t assume attic is OK because pressure is 48– Can seal zone-exterior (attic vents) to get

numbers into a better range– Read small pressure

73

Limitations/Cautions

• Re-check unusual measurements– “If a number is unbelievable, don’t believe it!”– Disconnected, misplaced or pinched hoses– Unknown fans– Mis-read gauges

• Its best to be able to get 50 Pascal before and after adding a hole

• Zone Connections can give exaggerated numbers in doing advanced on several zones, especially kneewalls

74

Improving Accuracy• Measure pressures directly; don’t subtract• Try to measure the smallest pressure

difference carefully• Do it again• For add-a-hole, try to add the hole to the

barrier with the largest pressure difference

75

New Zone Pressure Diagnostics • Study Completed by Center for Energy and

Environment, Michael Blasnik & Assoc. and the Energy Conservatory

• To test out how accurate the current tests are and when to use them

• Actually ended up creating a Hybrid method by combining Add a hole and Flow Method. To crosscheck and increase repeatability

76

When to Do Advanced Zonal Pressure Diagnostic Testing

• Important to access amount of leakage for

– IAQ issues (How much Leakage between Garage, or Moldy crawlspace and house)

– Durability Issues (How much leakage of moist house air leaking into attic of cold climate house)

77

New Zone Diagnostics

• Previously had programmed new hybrid method into a spreadsheet, and has now develop into a stand alone windows program, and currently developing for palm by The Energy Conservatory

• Rick Karg has added this to the TI-86 Calculator (Ziptest Pro2)

78

ZPD Utility for PC• Available at

www.energyconservatory.com• Select Products link then click

on Software• Scroll to bottom of page to

download installation file

79

• ZPD Study Available at Energy Center of Wisconsin website www.ecw.org

• To get directly to download page visit

http://www.ecw.org/ecw/productdetail.jsp?productId=384

80

Reference Articles • Home Energy Magazine May/June 2002

– Zone Pressure Diagnostics

• Home Energy Magazine Sept/Oct 1994– User Friendly Pressure Diagnostics

– BOTH OF THESE ARE AVAILABLE AT www.homeenergy.org

81

TECTITE & ZPD Utility• The ZPD Utility can be used with a handheld

manometer or by using TECTITE.• I use a form to collect data from TECTITE • Then am able quickly input data into ZPD Utility • TECTITE zone pressure info can be collected at

same time as multi-point blower door test.

82

Summary of Work Flow (1)

• Find Primary Zones and Thermal Boundaries

• Infrared scan before Blower Door

• Initial Blower Door Reading

• Use Infrared Camera with Blower Door to locate air leakage paths

83

Summary of Work Flow (2)• Direct ZPD for all Primary Zones

• Can use Pressure Ratio Chart to determine relative leakiness by estimating Net Free Area of Hole through one surface

• Direct Measurement on suspicious areas– Cantilevers, Soffits, Chases, Floor Cavities, Porches

• Check for Interconnections between zones

84

Summary of Work Flow (3)

• Advanced ZPD for all Attached Garages and Crawlspaces with moisture/mold issues.

• Advanced ZPD for Attics in cold climate areas, especially for tight houses with high moisture

• Use Visual Clues and Smoke Puffer from inside zone to help locate leaks in Pressure Boundary

85

Summary of Work Flow (4)• Where is Pressure Boundary,

– Is the Zone Inside or Outside

• Does it line up with Thermal Boundary

• Where should the Zone be and how will it be accomplished (Strategies for Air Sealing and Insulating)

• Explain recommendations to client (Mechanical, Air sealing, and Insulation)

– (e.g. leaving enclosed porch outside and insulating wall betweenthe house and the porch)

86

Summary of Work Flow (5)

Do Intermediate Blower Door Test• Did Zone Pressures move toward right

direction– Exterior Zone closer to 50PA WRT House– Interior Zone closer to 0PA WRT House– Pressure Pans in outside zone less than

1.0PA

87

Summary of Work Flow (6)

• Advanced ZPD to Measure remaining leakage to primary zones that were measured during the assessment

• Final Infrared Scan

• Take Final Blower Door Reading