Source Strength Source Strength Removal Rate Removal Rate Ventilation and IAQ

Random air leaks do not provide effective fresh air through a home Depends on temperature difference, wind, exhaust

Random air leaks do not provide effective fresh air through a home Where are the holes?

Random air leaks do not provide effective fresh air through a home Where are the holes?

Random air leaks do not provide effective fresh air through home Where are the holes?

Random air leaks do not provide effective fresh air through home Where are the holes?

Ventilation Basics How does ventilation work ? How much ventilation do I need in my climate ?

Ventilation is not a cure-all Limit and control pollutants at the source carbon monoxide asthma triggers moisture allergens particles radon VOCs chemicals etc. etc. etc.

Limit moisture sources Cook with lids Keep bathroom doors closed until moisture is removed No indoor clothes lines Limit indoor plants

Capture & Remove moisture at source: Showers Cooking Laundry

Ventilation Examples 1,500 Sq Ft House 70 degrees indoor air temperature 85% outdoor relative humidity Let’s look at what happens at … degrees outdoor temp ? degrees outdoor temp ? 3.What happens if we double the indoor moisture load?

Ventilation (Air Changes Per Hour) VS Indoor Relative Humidity (%) Indoor Relative Humidity (%) 1,500 ft sq house 70 0 F indoor temp 85 % outdoor RH 30 0 F outside temp typical moisture load.35 AC/h based on G. Tsongas l l.35 l l l l l l l l l l l l l Ventilation: Air Changes per Hour (AC/h) Extreme Ventilation Makes Little Difference

Ventilation (Air Changes per hour) VS Indoor Relative Humidity (%) Indoor Relative Humidity (%) 1,500 ft sq house 70 0 F indoor temp 85 % outdoor RH 50 0 F outside temp typical moisture load.35 AC/h based on G. Tsongas l l.35 l l l l l l l l l l l l Ventilation: Air Changes per Hour (AC/h)

Ventilation (Air Changes Per Hour) VS Indoor Relative Humidity (%) Indoor Relative Humidity (%) 1,500 ft sq house 70 0 F indoor temp 85 % outdoor RH 30 0 F outside temp typical moisture load 2 X moisture load 50 0 F outside temp typical moisture load 2 X moisture load.35 AC/h based on G. Tsongas l l.35 l l l l l l l l l l l l l Ventilation: Air Changes per Hour (AC/h)

Drying Potential of Outside Air: The colder the outside air, the more drying effect when this air is warmed inside Warm, humid air has much less drying potential (can cause problems)

Good News for Energy & Comfort When it’s cold outside: need less air exchange When it’s mild outside: need more exchange

Exhaust Moisture at the Source

Fan & Light Switch Fan delay time 1 to 60 minutes

If double pane windows are getting foggy on the room side, condensation & mold growth are on the way…

Comfort, Moisture, Noise, Pollen, Dust, Odors, Security Open Windows for Ventilation?

Ventilation Systems 1.Central Exhaust 2.Multi-port Exhaust 3.Heat Recovery Ventilator (balanced)

Dry air in Exhaust Fan Dry air in Wet air out Central Exhaust

Manual and Automatic Controls

Should operate 24 hours per day

2 Speed Whole House Fresh Air Fan Low speed 24/7 continuous fresh air High speed for odors odors moisture moisture VOCs VOCs particles particles etc. etc. Fan off delay timer Super Quiet

Motion Sensor turns fan to high speed turns fan to high speed 24/7 Low Speed CFM Setting Fan off delay timer

24/7 Low Speed CFM Setting Fan off delay timer

Air Inlets Built Into Window Frame

Through-the-Wall Fresh Air Vent

Ventilation Systems Central Exhaust Multi-port Exhaust Heat Recovery Ventilator (balanced)

Air out thru roof Air out from rooms in home Exhaust fan in Box Unit suspended in attic

Bedroom Central Zone Bathroom Bedroom

Bathroom exhaust grill about 20 CFM Continuous CFM High Speed

Bedroom exhaust grill about 10 CFM each room continuous

Ventilation Systems Central Exhaust Multi-port Exhaust Heat Recovery Ventilator (balanced)

Heat Recovery Ventilation Stale Moist Exhaust From House Tempered Fresh Air Into House Outside Fresh Air to House Stale House Air Exhaust

Outside Air Supply Air Return Air Exhaust Air Defrost Damper

Airborne Mold Sampling EPA, ACGIH* and other peer reviewed guidelines do not recommend airborne mold sampling as part of an investigation or remediation… *American Congress of Governmental Industrial Hygienists

It is very unlikely that airborne mold samples will provide evidence that cannot be more easily and reliably obtained by a thorough inspectio n Airborne Mold Sampling

Airborne Sampling can produce False Negatives.. but not False Positives “Absence of Evidence is NOT Evidence of Absence”

Consensus is that traditional methods used to identify increased mold exposure do not reliably predict increased health risks. California Department of Public Health Statement on Building Dampness, Mold, and Health, September 2011

Current practices for collection, analysis, and interpretation of environmental samples for mold… cannot be used to quantify health risks posed by dampness and mold in buildings or to guide health- based actions. California Department of Public Health Statement on Building Dampness, Mold, and Health, September 2011

Current consensus does not justify the differentiation of some molds (such as Stachybotrys species) as “toxic molds”

California Department of Public Health Statement on Building Dampness, Mold, and Health, September 2011 The only types of evidence that have been related consistently to adverse health effects are: current or past water damage, damp materials, visible mold, mold odor. But not the number or type of mold spores nor the presence of other markers of mold in indoor air or dust.

The most effective tool for locating mold growth and building dampness: a detailed site inspection, understanding moisture dynamics, building science fundamentals. (Light, 2009)

One set of investigations based on detailed building inspection, Parallel investigations based on mold testing. Results indicated that extensive collection of air and surface samples failed to identify mold growth in addition to that observed using visual indicators. Moreover, the inspector using visual cues located hidden mold growth undetected by sampling in half of the cases (6 of 12). (Light, 2009) 12 cases where opposing experts evaluated the same water damaged site: