Indoor Air & Moisture Issues

1. Indoor Air & Moisture Issues

2. Indoor Pollutants Carbon monoxide (CO) Tobacco smoke Nitrogen oxides, hydrocarbon dust Volatile organic compounds (VOC) Radon Biological Particles (bacteria, , viruses, dust mites, cockroaches, fungi, mold, raw sewage, rotting wood) Asbestos and Fiberglass Lead-based paints Water vapor

3. Indoor Pollutants How will you deal with these? • Lifestyle (pets outside, door mats, no shoes indoors, regular cleaning) • Careful product purchase decisions (low VOC) • Hard floor surfaces in lieu of carpeting • Sealed combustion appliances (furnace, fireplace) • House pressure balancing (jump ducts, transfer grills) • Moisture management (humidity control) • Ventilation • Whole house • Spot (bathrooms, kitchen, crawl spaces for radon) • Air filtration

4. Indoor Pollutants How will you deal with these? Air filtration

5. Indoor Pollutants How will you deal with these? Air filtration

6. Electronic air cleaner Media air cleaner 4” Return grille media filter Indoor Pollutants How will you deal with these? Air filtration

7. Indoor Pollutants Efficiency at 0.3 Micron Particles 100% 75% 50% 25% 0% 72% 15% < 1% 4-inch media filter 1-inch media filter electronic air cleaner

9. Moisture • Moisture is the number one pollutant in homes • Need to be aware of its sources • Basic knowledge of determining moisture levels • Solving moisture problems

10. Dealing With Moisture • Keep water out • Roof, plumbing, grading of ground…fix problems • Understand that moisture will get in • Ventilation is needed • Make sure moisture can get out • Material selection (vinyl wallpaper is a bad choice) BPI Analyst Certification – Basic Principles of Energy

11. Moisture Movement Through Buildings • Moisture in buildings can be tracked to one or more of the following (in order of importance) • Liquid flow: Roof leaks, plumbing leaks, ground water… • Capillary seepage: Liquid water being pulled into a material or assembly • Air movement: Carrying water vapor into or out of a building and its cavities • Vapor diffusion: Vapor will move through solid objects depending on the object’s permeance and the vapor pressure

12. Controlling Moisture … • 1 inch of rain on 1,000 sq. ft. roof = 623 gallons • High water table • Foundation plants • Leaking water spigot

14. Moisture Movement • Vapor pressure: Vapor pressure is created by different amounts of water vapor in two different air masses. Moves from high to low. • Relative humidity: The percentage of the maximum moisture that air can hold at a given temperature • The higher the temperature of the air, the more moisture it can hold BPI Analyst Certification – Basic Principles of Energy

15. Relative Humidity • Key point: relative humidity (RH) changes as temperature changes • When cooled enough, air at 50% RH, for example, will hit 100% RH and the moisture in the air will condense on cool surfaces • In the winter, warm indoor air is forced out of a building • In the summer, hot humid air is pulled into an air conditioned space……. under this condition, there is a potential for MOLD.

16. Moisture Concepts Vapor pressure: Vapor pressure is created by different amounts of water vapor in two different air masses. Moves from high to low.

17. MaterialsPermeance The ability of a material to restrict moisture flow is based on its “perm rating” Materials with a perm rating of 1 or less are considered a “vapor retarder”

18. Thermal Barrier Air Barrier Unconditioned Air Conditioned Air

19. Structural Design Understand how design features can cause weaknesses vapor barrier • How a building fits together can give you hints as to where there may be weaknesses • Shafts and Soffits (covered already) • Slab/Crawlspace/Basement • Framing • Porches/Garages • Bonus Rooms • Stairs • Split Levels

20. Slab/crawlspace/basement Trend to build or retrofit to sealed crawlspaces. Main concern – vented crawlspace. If there is a building component (wall, shaft…) that is connected to a vented crawlspace and vented attic, high potential for problems.

21. Framing Balloon framing: Found in older homes, may have stud walls that are two stories high and usually do not have top or bottom plates. This may result in the wall being open to the basements/crawlspaces and the attic.

22. Framing Platform framing, each floor serves as a platform for the next floor. Has top and bottom plates.

23. Porches/Garage Issue with multi-story structures – Is there insulation and an air barrier at the rim joist that is hidden by the porch or garage?

24. Bonus Rooms

25. Split-Levels

26. Moisture Concepts Diffusion vs. Air Movement

27. A Primer on Air Flow • For air to flow you need a hole and a pressure. • No hole, no flow • No pressure, no flow

28. 1 cubic foot 1 cubic foot If air is exhausted out of a building, outside air must replace it If you pull air into a building, inside air must be forced out

29. CFM50 Leakage Tests • Provides information on how leaky the house is. • Remember, how leaky, not how much leakage. Amount of air movement depends on pressure! • Post air sealing test can give valuable feedback on the success of your work. • Find where the holes are. • Predictions on the impact of work.

30. What does a CFM50 value tell you about the house? • CFM50 is like a 20 mile per hour wind blowing on all sides of the house. • From this value you can estimate the natural leakage of a home (see appendix E in the BD manual). • The CFM50 value can give you a good indication of the total size of all the holes in a home. • A tenth (remove the last digit) of the CFM50 number is about equal to the square inches of holes in the house. 1500 CFM50 = about 150 sq. inches of holes.

31. Door Closure The average pressure that natural forces will put on a house are between 1.5 Pa (low desert) to 3 Pa (high country). Pressure created by door closure can be many times higher than natural pressure. The higher the pressures, the higher the infiltration rate. Room pressure tests will show if there is a problem and help determine the solution. BPI Analyst Certification – Pressure Diagnostics

32. 140º Attic Doors Closure 100º outside 1000 CFM supply flow 1000 CFM return flow Return side will go negative. Supply side will go positive Close a door and block the flow back to the return.

33. Room Pressure 6.5 Room WRT outside, interior door of room you are testing closed, air handler on. Test every room with a door and supply or return register. BPI Analyst Certification – Pressure Diagnostics

34. The following video is a time lapse infrared of a home under negative 3 Pa pressure for 40 minutes. Note starting temperatures. 80.7° 82.7° 80.8° 80.0°

36. Temperatures after 40 minutes. 8 to 12 degree increase in surface temperatures. 92.5° 90.9° 88.9° 87.3°

37. The pressure is getting to me!

38. Flex Duct Jump Duct Air Flow Air Flow Main Body of House Inside Bedroom Transfer Grill House pressure balancing

39. House pressure balancing

40. Avoid negative pressuresin hot-humid climates Infiltration of warm, humid air: • Into walls • Through chases • Into rooms Condensation on cool surfaces

41. The “Perfect House”

42. Indoor Pollutants Water vapor

43. Sources of Home Moisture An average family of four can generate over six gallons of moisture per day. Shower (excludes towels & spillage) 1.0 pt / 10 minute shower Clothes drying (vented indoors) 5.0 pt/ load Combustion (unvented space heater) 7.6 pt/ gallon of kerosene Cooking dinner (family of four) 1.2 pt(1.6 if gas cooking) Floor mopping 1.5 pt/ 50 sq. ft. Respiration (family of four) 0.4 pt/ hour Desorption of materials: seasonal 6 to 17 pt/ day New construction                             10+ pt/day Ground moisture migration Up to 100 pt/day 1.0 pint can increase the RH by about 8% in a 1,500 sq. ft. single floor home.

44. Optimum Indoor Relative Humidity Levels.

45. Sensible and Latent Heat • Sensible heat: The basic relationship between energy and temperature Example: 1 Btu = 1° increase in temperature of 1 lb of water

46. Sensible and Latent Heat • Latent heat: The heat absorbed or released when a material changes phase between a solid and a liquid or between a liquid and a gas

47. AIR CONDITIONING • Utilizes the properties of latent heat to move heat through a forced air distribution system • Cooling moves heat out of the house • Removes Latent heat first • Condenses water vapor back into liquid

48. SIZING • Over-sizing has a negative effect on energy use, comfort, equipment life, and system costs: • Oversized systems run for a short period and do not reach steady state efficiency (think of city vs. highway driving). Impacts both cost and life. • Short run times mean that the air does not get mixed, causing hot spots. • Short run times will not remove humidity, increasing comfort problems. • Over sized equipment costs more to install.

49. STEADY STATE EFFICIENCIES Steady State SEER Over sized system replaces steady state with start-up, lowering efficiency. Start-up Time Mechanical devices take time to go from start up to their peak, steady state efficiency. Some A/C units will take minutes. (SEER incorporates this start up time)

50. Kitchen & Bath Moisture Control • Bathrooms, kitchens and utility areas should be vented to the “outside” – never to attic or crawl space. • Exhaust vents rarely discharge rated cfm