Formaldehyde in High Performance Homes with Outdoor Air Intakes Melissa Malkin-Weber Advanced Energy, Raleigh, North

1. Formaldehyde in High Performance Homes with Outdoor Air Intakes Melissa Malkin-Weber Advanced Energy, Raleigh, North Carolina ACI Conference Kansas City, Missouri April, 2009 This presentation will be archived at www.healthierhomes.org as well as the ACI website.This presentation will be archived at www.healthierhomes.org as well as the ACI website.

2. Study Partners HUD Office of Healthy Homes and Lead Hazard Control Advanced Energy National Institutes of Environmental Health Sciences (NIH) UNC School of Medicine Center for Environmental Medicine, Asthma, and Lung Biology Habitat for Humanity We brought together experts from several disciplines to investigate the indoor environment of energy efficient houses -HUD’s national program expertise -Advanced Energy’s applied building science on how to get houses delivered in the real world marketplace -NIH on measuring indoor allergens -UNC on environmental asthma and patient outcomes -Habitat for Humanity’s network of affordable builder affiliatesWe brought together experts from several disciplines to investigate the indoor environment of energy efficient houses -HUD’s national program expertise -Advanced Energy’s applied building science on how to get houses delivered in the real world marketplace -NIH on measuring indoor allergens -UNC on environmental asthma and patient outcomes -Habitat for Humanity’s network of affordable builder affiliates

3. Outline Why formaldehyde? High performance house context Study Hypothesis Intervention specifications Measurement method Results What does that mean? Next steps

4. Human carcinogen Short term effects respiratory irritation eye irritation Suggestive evidence of links to respiratory symptoms Multiple indoor sources Long term = BAD Short term = non-trivial Health impacts (long, short term) Many sources in modern environment It’s a surrogate for all the other chemicals. We just tested the F in alphabet soup. The entire chemical soup is still an issue, even after EPA and California regulate specific sources of formaldehyde. Long term = BAD Short term = non-trivial Health impacts (long, short term) Many sources in modern environment It’s a surrogate for all the other chemicals. We just tested the F in alphabet soup. The entire chemical soup is still an issue, even after EPA and California regulate specific sources of formaldehyde.

5. Building and Consumer Products Pressed wood products (urea-formaldehyde resins) Urea-formaldehyde foam insulation Fabric finishes Paper products Cosmetics Detergents More Combustion (heaters or furnaces) Secondary reactions Terpenes interact with ozone to produce formaldehyde and other byproducts People

6. A high performance home specification can improve the indoor environment related to asthma-relevant outcomes, overcoming homeowner behaviors. Is the ventilation sufficient to: Do no harm? Create BETTER indoor air quality than in houses with leaky shells and ducts? The goal was to test available specifications and processes that would lead to a home that performs effectively in the real world High performance homes come from the energy world, and the steps are transferrable to health interventions -specifications are important – low e windows, insulation R value, HVAC sizing -process so that the people putting the parts together know how and can do it -quality assurance testing to make sure it got done -Feedback loop Overcoming homeowner behaviors -homeowners are an important part of reality -lots of excellent research on health interventions for which the resident is washing sheets more often, vacuuming with a HEPA vac, shrink-wrapping the cat, or freezing the kids teddy bear. The goal was to test available specifications and processes that would lead to a home that performs effectively in the real world High performance homes come from the energy world, and the steps are transferrable to health interventions -specifications are important – low e windows, insulation R value, HVAC sizing -process so that the people putting the parts together know how and can do it -quality assurance testing to make sure it got done -Feedback loop Overcoming homeowner behaviors -homeowners are an important part of reality -lots of excellent research on health interventions for which the resident is washing sheets more often, vacuuming with a HEPA vac, shrink-wrapping the cat, or freezing the kids teddy bear.

7. Methods - Study Design 36 homes in central North Carolina (mixed humid climate) 20 intervention (“healthy homes intervention package”) High performance builder process 16 non-intervention homes Building-code compliant construction Typical construction 3 neighborhoods In some ways an excellent comparison group But there is no way to standardize people, and our study did not seek to modify behaviors3 neighborhoods In some ways an excellent comparison group But there is no way to standardize people, and our study did not seek to modify behaviors

8. Features of the Intervention Tight construction Interior moisture management Improved insulation “Right-sized” HVAC Pressure balancing Outside air ventilation Closed crawl space These houses had the ‘high performance elements mentioned above that go in all the SystemVision program houses: Tight construction - Special framing techniques and improved insulation systems help reduce internal leaks and drafts. Interior moisture mgmt - Using “right- sized” HVAC systems, multiple air ducts, return air grilles , bathroom and kitchen fans, and mechanical ventilation helps remove to remove moisture that naturally passes through the home. Outdoor air ventilation - Efficient delivery and filtration systems reduce dust, odors and indoor contaminants. Improved insulation system - Enhanced insulation and framing techniques help minimize voids and gaps while the use of Low-E glass and higher thermal properties (R-Value) add to increased energy-efficiency. Right sized HVAC - High efficiency equipment, multiple air ducts and return grilles help circulate fresh air, decrease humidity and reduce energy use. Pressure balancing- Return air ducts, transfer grilles or jumper ducts help balance pressure throughout the home, enabling air to circulate more easily. Combustion safety -Combustion appliances are sealed or power-vented to help avoid the build-up of carbon monoxide. We souped up the system vision moisture managemnet and filtration by adding a closed crawl space to reduce the load of moisture that would typically enter the house through the crawl space vents, the crawl space floor, and by wicking up the concrete block piers. We DID NOT CONTROL construction materials, cabinets, floor coverings, or what the occupants brought in. So no standardization of sources of VOCs like formaldehyde. To ensure all standards were met, each home received a minimum of three quality control visits. The three quality control visits occurred after the framing, insulation and pre-occupancy stages. The programs include a two-year guarantee for the amount of energy the home will use for heating and cooling. The guarantee is based on energy use predicted by a software model. Additional details on these standards and process can be found on the SystemVision web site at www.systemvision.org. The same standards are used in the national Environments for Living program in which over 150,000 homes have been built across the United States. These houses had the ‘high performance elements mentioned above that go in all the SystemVision program houses: Tight construction - Special framing techniques and improved insulation systems help reduce internal leaks and drafts. Interior moisture mgmt - Using “right- sized” HVAC systems, multiple air ducts, return air grilles , bathroom and kitchen fans, and mechanical ventilation helps remove to remove moisture that naturally passes through the home. Outdoor air ventilation - Efficient delivery and filtration systems reduce dust, odors and indoor contaminants. Improved insulation system - Enhanced insulation and framing techniques help minimize voids and gaps while the use of Low-E glass and higher thermal properties (R-Value) add to increased energy-efficiency. Right sized HVAC - High efficiency equipment, multiple air ducts and return grilles help circulate fresh air, decrease humidity and reduce energy use. Pressure balancing- Return air ducts, transfer grilles or jumper ducts help balance pressure throughout the home, enabling air to circulate more easily. Combustion safety -Combustion appliances are sealed or power-vented to help avoid the build-up of carbon monoxide. We souped up the system vision moisture managemnet and filtration by adding a closed crawl space to reduce the load of moisture that would typically enter the house through the crawl space vents, the crawl space floor, and by wicking up the concrete block piers. We DID NOT CONTROL construction materials, cabinets, floor coverings, or what the occupants brought in. So no standardization of sources of VOCs like formaldehyde. To ensure all standards were met, each home received a minimum of three quality control visits. The three quality control visits occurred after the framing, insulation and pre-occupancy stages. The programs include a two-year guarantee for the amount of energy the home will use for heating and cooling. The guarantee is based on energy use predicted by a software model. Additional details on these standards and process can be found on the SystemVision web site at www.systemvision.org. The same standards are used in the national Environments for Living program in which over 150,000 homes have been built across the United States.

9. 7 Steps to high-performance housing Standards Plan Review Contractor/Subcontractor training On-site quality control Performance testing Certification/Guarantee Servicing the Guarantee A critical distinction is that these high performance homes were built using a program designed to consistently deliver the promised performance. It’s a systems approach.A critical distinction is that these high performance homes were built using a program designed to consistently deliver the promised performance. It’s a systems approach.

11. Real-World Research No source control specified (formaldehyde or other volatile organic compounds). Builders used their typical carpets and cabinetry Study participants not asked change behaviors We are testing an intervention protocol based on current market programs that we know can be adopted. Our starting point is what can be readily deployed. Again, we’re aiming at a house that performs in the “lived in condition” We are testing an intervention protocol based on current market programs that we know can be adopted. Our starting point is what can be readily deployed. Again, we’re aiming at a house that performs in the “lived in condition”

12. The Ventilation Package Goal is to provide outside air to dilute pollutants generated indoors Offset the reduced infiltration through the envelope and ducts when house is tightened Used in 2 successful high performance homes programs

13. Exhaust Ventilation Spot exhaust Performance tested Kitchen (exhausts >100 cfm) Baths (exhausts >50 cfm) Spot exhaust fans were required in the kitchen and bathrooms. Exhaust ratings conform to ASHRAE Standard 62.2. Performance tested using flow pan Common failure is from packing tape on exhaust Insulated metal or flexible ducts all connections were sealed with mastic. Directly to the outdoorsSpot exhaust fans were required in the kitchen and bathrooms. Exhaust ratings conform to ASHRAE Standard 62.2. Performance tested using flow pan Common failure is from packing tape on exhaust Insulated metal or flexible ducts all connections were sealed with mastic. Directly to the outdoors

14. Outdoor air intake with Air Cycler 20 minutes per hour Flow 10 cubic feet per minute (CFM) in each bedroom plus 10 CFM. A 3 bedroom house ? 40 CFM The timer turns on the air handler for twenty minutes out of every hour when the thermostat is not calling for heating or cooling. This brings in a consistent amount of outdoor air, even when the homeowner does not use their heating or cooling system during mild-weather times of the year. In mixed-humid climates such as the study location, there is concern that providing continuous ventilation will introduce more moisture load than the heating, ventilation and air conditioning (HVAC) system can wring out of the air, thereby generating moisture-related problems in the home. Controls for air cycler (typically placed somewhere inconspicuous like a closet or even in crawl space near air handler After this study, the SystemVision high performance homes program eliminated use of the air cycler due to comfort complaints from homeowners and data that showed that the HVAC was cycling on daily even in the shoulder seasons Flow rate is equivalent to ASHRAE 62.2, but runs intermittently, not continuous. The timer turns on the air handler for twenty minutes out of every hour when the thermostat is not calling for heating or cooling. This brings in a consistent amount of outdoor air, even when the homeowner does not use their heating or cooling system during mild-weather times of the year. In mixed-humid climates such as the study location, there is concern that providing continuous ventilation will introduce more moisture load than the heating, ventilation and air conditioning (HVAC) system can wring out of the air, thereby generating moisture-related problems in the home. Controls for air cycler (typically placed somewhere inconspicuous like a closet or even in crawl space near air handler After this study, the SystemVision high performance homes program eliminated use of the air cycler due to comfort complaints from homeowners and data that showed that the HVAC was cycling on daily even in the shoulder seasons Flow rate is equivalent to ASHRAE 62.2, but runs intermittently, not continuous.

15. Outdoor Air Intake Configuration Six-inch flex duct Vent at the foundation connected to return air plenum Six-inch manual balancing damper in flex duct near outside intake Damper performance tested Cleanable filter installed at intake The outside air is brought into the return air plenum. When the heating and cooling is called for, the air is conditioned before being distributed. If no heat/cool, the air handler simply is circulating outdoor air. Filter excludes insects, birds, cats...The outside air is brought into the return air plenum. When the heating and cooling is called for, the air is conditioned before being distributed. If no heat/cool, the air handler simply is circulating outdoor air. Filter excludes insects, birds, cats...

16. Home Characteristics Intervention (I) and non-intervention (N) homes over several categories. The recirculation fans are shown with a value of 0 CFM because they did not vent to the outside. The non-intervention homes had more leaks in the building envelope and ducts. NI had less powerful spot ventilation. None of the non-intervention homes had spot ventilation in the kitchen—all had recirculating fans, which force odors and moisture from cooking back into the kitchen by means of a fan located in the vent hood. Intervention (I) and non-intervention (N) homes over several categories. The recirculation fans are shown with a value of 0 CFM because they did not vent to the outside. The non-intervention homes had more leaks in the building envelope and ducts. NI had less powerful spot ventilation. None of the non-intervention homes had spot ventilation in the kitchen—all had recirculating fans, which force odors and moisture from cooking back into the kitchen by means of a fan located in the vent hood.

17. Exhaust

18. Is the Ventilation Reducing Chemical Pollutants? Seven-day formaldehyde sample 40-day period beginning August 2005 (all humid season) Length of time to offgas varied Median age of the intervention homes was 10 months (minimum 5 months) Median age of non-intervention homes was 20 months Recall that we are measuring the F in the alphabet soup of pollutants in indoor air. Due to construction delays, the intervention homes were built later than the non-intervention homes. Recall that we are measuring the F in the alphabet soup of pollutants in indoor air. Due to construction delays, the intervention homes were built later than the non-intervention homes.

19. Sampling Method UMEx 100 Passive Samplers (3M) Level of detection of 0.03 ug (2 ppb)

20. Average Formaldehyde Levels No significant difference was found between formaldehyde levels in the intervention and non-intervention groups. No significant difference was found between formaldehyde levels in the intervention and non-intervention groups.

21. Available Guidelines 100 ppb action level (Health Canada and the World Health Organization) 40 ppb eight-hour average (Health Canada) 7 ppb eight-hour and chronic Reference Exposure Level (California) The health guidelines vary by organization The 7 ppb level is lower than what is often present in ambient outdoor air. The health guidelines vary by organization The 7 ppb level is lower than what is often present in ambient outdoor air.

22. Home by Home Levels in individual homes varied between 0.02 ppm and 0.122 ppm The majority of homes were below the 100 ppb action level on the week we measured Most exceeded the Health Canada 8-hour average And all exceeded the California recommendations FEMA trailers averaged 77ppb, with a range of 3ppb-590 ppb Sample staff house was 65ppb Levels in individual homes varied between 0.02 ppm and 0.122 ppm The majority of homes were below the 100 ppb action level on the week we measured Most exceeded the Health Canada 8-hour average And all exceeded the California recommendations FEMA trailers averaged 77ppb, with a range of 3ppb-590 ppb Sample staff house was 65ppb

23. Summary The high performance program didn’t harm the homeowners Tight envelope and tight ductwork did not create higher levels of formaldehyde … Compared to homes with unplanned ventilation (duct and envelope leakage). Ventilation package seems to have compensated for reducing the infiltration & leakage But formaldehyde levels are still above guidance standards At 10 months after move-in for intervention homes At 20 months after move-in for non-intervention homes It is possible that the intervention homes would be distinguishable if we could adjust for the reduced offgassing time. Because there was just one sample, we can’t make that adjustment. Phase 2 study eliminates the difference in offgassing time.It is possible that the intervention homes would be distinguishable if we could adjust for the reduced offgassing time. Because there was just one sample, we can’t make that adjustment. Phase 2 study eliminates the difference in offgassing time.

24. What Can We Do to Reduce Formaldehyde (and the rest of the chemicals in the soup)? Continuous ventilation may be “enough” outdoor air to dilute formaldehyde How do we get “continuous” without moisture overload? ERV Ventilating dehumidifier Other? Considerations: Tradeoff between moisture and dilution How much moisture is introduced? Energy penalty? Initial and operational costs? The Offerman study suggests that continuous ventilation can get formaldehyde down to low levels… But in humid and mixed humid climates, there is always a tradeoff between dilution and moisture. What are the options? (ERV, ventilating dehu, other?) In selecting a continuous option, we need to evaluate: the amount of moisture introduced, the energy penalty, purchase and operational costs.The Offerman study suggests that continuous ventilation can get formaldehyde down to low levels… But in humid and mixed humid climates, there is always a tradeoff between dilution and moisture. What are the options? (ERV, ventilating dehu, other?) In selecting a continuous option, we need to evaluate: the amount of moisture introduced, the energy penalty, purchase and operational costs.

25. Excluding the moisture from soil and outdoor air in a house with this ventilation configuration didn’t keep moisture below 50% RH in these houses (dust mite control target). Didn’t even keep it below 60% (mold control target). Visual inspection of houses in this research study didn’t show mold, but other houses in the SystemVision program did have mold and comfort complaints. The air cycler strategy is not currently used by the program. The various moisture management strategies that we used in the intervention houses did not create a house with detectably lower RH than the non intervention houses. Some Possible explanations: the ventilation timer brings in moist outside air when it runs every 20 minutes. So perhaps without the closed crawl, we would have seen higher moisture in the intervention houses. Maybe the closed crawl produced indoor moisture reductions that offset the moisture from the dilution. We may not be seeing differences in moisture problems of the magnitude to cause health issues because they are relatively new, and some of the building failure issues associated with, e.g., condensation on cold wall surfaces because of insulation gaps , just haven’t manifested in the control homes, or don’t show up as RH change in the ambient RH but rather show up in smaller pockets. Another important factor is that these affordable houses have more people in them than market-rate construction: 4.14 on average, compared to 2.5 for NC overall. So the moisture burden from cooking, laundry, bathing, and breathing is higher than we’d expect in market rate housing. Excluding the moisture from soil and outdoor air in a house with this ventilation configuration didn’t keep moisture below 50% RH in these houses (dust mite control target). Didn’t even keep it below 60% (mold control target). Visual inspection of houses in this research study didn’t show mold, but other houses in the SystemVision program did have mold and comfort complaints. The air cycler strategy is not currently used by the program. The various moisture management strategies that we used in the intervention houses did not create a house with detectably lower RH than the non intervention houses. Some Possible explanations: the ventilation timer brings in moist outside air when it runs every 20 minutes. So perhaps without the closed crawl, we would have seen higher moisture in the intervention houses. Maybe the closed crawl produced indoor moisture reductions that offset the moisture from the dilution. We may not be seeing differences in moisture problems of the magnitude to cause health issues because they are relatively new, and some of the building failure issues associated with, e.g., condensation on cold wall surfaces because of insulation gaps , just haven’t manifested in the control homes, or don’t show up as RH change in the ambient RH but rather show up in smaller pockets. Another important factor is that these affordable houses have more people in them than market-rate construction: 4.14 on average, compared to 2.5 for NC overall. So the moisture burden from cooking, laundry, bathing, and breathing is higher than we’d expect in market rate housing.

26. Does a high performance house with closed crawl space manage RH ? Crawl space RH stayed below 70% Expect mold suppression in crawl and reduced mold in house House RH was not reduced Closed crawl space + outdoor air doesn’t bring the living space to target RH Introducing outdoor air does not dry the house Closed crawl couples crawl RH to house Wall-vented crawls remain coupled to outdoor RH The mold photo here is to underline the point that a wet crawlspace is very likely to grow mold, so drying the crawl space is very important It is common to hear people talking about ventilation as if outdoor air will dry the house. In the mixed humid climate, it does NOT dry the house. EPA’s Energy Star Indoor Air Quality label requires labeled houses in warm-humid climates to provide dehumidification that control to <60% RH. The mold photo here is to underline the point that a wet crawlspace is very likely to grow mold, so drying the crawl space is very important It is common to hear people talking about ventilation as if outdoor air will dry the house. In the mixed humid climate, it does NOT dry the house. EPA’s Energy Star Indoor Air Quality label requires labeled houses in warm-humid climates to provide dehumidification that control to <60% RH.

27. Average house RH and Temperature More detailed breakout of RH and temp indoors (measured at the return). The shoulder seasons are staying below 52% RH, but the wet season is above 60% on average. We’d like houses to stay below 60% RH. More detailed breakout of RH and temp indoors (measured at the return). The shoulder seasons are staying below 52% RH, but the wet season is above 60% on average. We’d like houses to stay below 60% RH.

28. Source Control Formaldehyde in wood products may drop California regulations EPA intends to regulate Formaldehyde in other products? Other VOCs in building materials and consumer products…

29. Phase 2 -- Ventilation Comparison of houses is more “apples to apples” Measure tight houses with and without outdoor air (no air cyclers)

30. Change Intervention Configuration Mechanical dehumidification (<50% RH) More affordable closed crawl configuration Measure More Precisely Pollutants Air changes per hour Does filtration change anything? Phase 2 -- other changes to intervention Mechanical dehumidification – high efficiency, in a tight house, with moisture suppression Minimally code-compliant closed crawl – does it work over time. Phase 1 configuration is very robust and costs are coming down in our area, but the cost cuts into marketability Effective ventilation – we’re testing this configuration, and there's lot of other research going on too, so as a community we put it together and figure out how to go forward BTW, the ACI Retrofit Summit in 2007 concluded that our current HVAC systems won’t get us where we want to go, and they started from scratch and created some blue sky ideas. Mechanical dehumidification – high efficiency, in a tight house, with moisture suppression Minimally code-compliant closed crawl – does it work over time. Phase 1 configuration is very robust and costs are coming down in our area, but the cost cuts into marketability Effective ventilation – we’re testing this configuration, and there's lot of other research going on too, so as a community we put it together and figure out how to go forward BTW, the ACI Retrofit Summit in 2007 concluded that our current HVAC systems won’t get us where we want to go, and they started from scratch and created some blue sky ideas.

31. Melissa Malkin-WeberResearch Director for Applied Building Science(919) 857-9000mweber@advancedenergy.orgwww.healthierhomes.org

32. References Health Canada. Residential Indoor Air Quality Guideline: Formaldehyde. Ottawa, Ontario, April 2006. Centers for Disease Control and Prevention (CDC). Final report on formaldehyde levels in FEMA-supplied travel trailers, park models, and mobile homes July 2, 2008 Davis B, Dastur C. Moisture performance of closed crawl spaces and their impact on home cooling and heating energy in the southeastern United States. U.S. Department of Energy Oak Ridge National Laboratory and ASHRAE Performance of the Exterior Envelopes of Whole Buildings IX International Conference 2004. Clearwater Beach, Florida. Destaillats H. Indoor chemistry of ozone with household product constituents. ASHRAE IAQ 2007 Conference. Baltimore, Maryland. Grimsrud DT, Turk BH, Prill RJ, Harrison J, Revzan KL. Effects of house weatherization on indoor air quality. lndoor Air '87: Proceedings of the 4th International Conference on lndoor Air Quality and Climate, Berlin (West). August 1987. Guo L, and Lewis JO. Carbon dioxide concentration and its application on estimating the air change rate in typical Irish houses. International Journal of Ventilation 2007; Vol 6, No 3. Hodgson AT, Beal D. Sources of formaldehyde, other aldehydes and terpenes in a new manufactured house. E.O. Lawrence Berkeley National Laboratory 2002. Contract2002. Contract number DE-AC03-76SF00098. Available at http://eande.lbl.gov/ied/viaq/. Kelly TJ, Smith DL. Satola J. Emission rates of formaldehyde from materials and consumer products found in California Homes. Environmental Science and Technology 1999; 33: 81-88. Loh, MM, Levy JI, Spengler JD, Houseman EA, Bennett DH. Ranking cancer risks of organic hazardous air pollutants in the united states. Environmental Health Perspectives 2007; Vol 115, Num 8. (continued next slide)

33. References, continued Malkin-Weber M, Coulter J, Hannas B, Dixon T. High performance intervention houses in north carolina – an attempt to control indoor relative humidity at 50% year round. Indoor Air 2008, Copenhagen, Denmark. http://www.indoorair2008.org/. Meier, A. Infiltration: just ACH50 divided by 20? Home Energy, 1994 Mendell, MJ. Indoor residential chemical emissions as risk factors for respiratory and allergic effects in children: a review. Indoor Air 2007; 17: 259–277 Office of Environmental Health Hazard. Assessment Technical Support Document For the Derivation of Noncancer Reference Exposure Levels, Appendix D.1 Individual Acute, 8-Hour, and Chronic Reference Exposure Level Summaries. Oakland: California 2008 Offerman F, Brennan S, Roberson J, Springer D Woo T. Window Usage, Ventilation, and Formaldehyde Concentrations in New California Homes: Summer Field Sessions. ASHRAE IAQ 2007 Conference, Baltimore, Maryland. WHO - World Health Organization. Environmental health criteria for formaldehyde. 1989. Geneva, Switzerland: World Health Organization; Volume 89

34. Following are additional slides with supplementary information that will be discussed further in final report and articles

35. Field Research in Occupied Houses Challenges Scheduling large sample of homes – weekend/evenings Ensuring pickup in acceptable time window Ensuring samples labeled accurately and observational data collected accurately in often-chaotic environment

36. Snapshot of Ventilation Rates (Air Changes Per Hour) excluding impact of air cycler and ventilation fans Using the measured air tightness of the home we calculated air changes per hour the intervention homes experienced compared to the leaky non-intervention homes using a common calculation based on the air flow across the blower door at 50 pascals (Meier, 1994). The air changes per hour calculated in this manner are a rough estimate of actual air changes (Gao, 2007). On average, the intervention homes are calculated to have about 25% fewer air changes per hour than the non-intervention group as shown in Table 2.Using the measured air tightness of the home we calculated air changes per hour the intervention homes experienced compared to the leaky non-intervention homes using a common calculation based on the air flow across the blower door at 50 pascals (Meier, 1994). The air changes per hour calculated in this manner are a rough estimate of actual air changes (Gao, 2007). On average, the intervention homes are calculated to have about 25% fewer air changes per hour than the non-intervention group as shown in Table 2.

37. Formaldehyde Sampling The results are only as good as the field details. Tracking data, deploying samplers, keeping samples on ice were some of the critical details of our field process. The results are only as good as the field details. Tracking data, deploying samplers, keeping samples on ice were some of the critical details of our field process.

40. We submetered compressor & hot water and read main meters monthly We submetered compressor & hot water and read main meters monthly

41. Shows consistency through year from month to month Higher in winter (not during summer break); What other reasons can you imagine? Shows consistency through year from month to month Higher in winter (not during summer break); What other reasons can you imagine?

42. Results – energy use Space conditioning saving 13.7% total (~5.8% of total energy savings) 3.6% June – August/ 0.8% July – September Intervention homes use more energy in every other category (non-space conditioning) Data from July – Dec 06 Data from July – Dec 06

43. Space conditioning saving 13.7% total (~5.8% of total energy savings) 3.6% June – August/ 0.8% July – September Intervention homes use more energy in every other category (non-space conditioning) Space conditioning saving 13.7% total (~5.8% of total energy savings) 3.6% June – August/ 0.8% July – September Intervention homes use more energy in every other category (non-space conditioning)

44. Baseload includes hot water Baseload includes hot water

46. National household size of 2.57 people 2.49 for NC 2.51 for Wake Co. 2.30 for Raleigh 2.40 for Durham Co. 2.37 for Durham 4.14 for this study

47. Health and Energy Performance –The Tip of the Iceberg AEC has looked at the subject of health in houses from a bunch of different perspectives (list studies in occupied houses) The goal is to find a prescription & a process for a building that performs in all of the different ways (energy, comfort, health, durable) We are always looking for collaborators to move the practical knowledge forward. We are always looking for ways to get what works out into the market placeAEC has looked at the subject of health in houses from a bunch of different perspectives (list studies in occupied houses) The goal is to find a prescription & a process for a building that performs in all of the different ways (energy, comfort, health, durable) We are always looking for collaborators to move the practical knowledge forward. We are always looking for ways to get what works out into the market place

48. Phase 2 -- Ventilation Comparison of houses is more “apples to apples” Measure tight houses with and without outdoor air (no air cyclers) Measure tight houses with air cyclers Measure leakier houses without air cyclers Older houses – longer to offgas

49. Change Intervention Configuration Mechanical dehumidification (<50% RH) More affordable closed crawl configuration Measure More Precisely Pollutants Air changes per hour Does filtration change anything? Next Steps Mechanical dehumidification – high efficiency, in a tight house, with moisture suppression Minimally code-compliant closed crawl – does it work over time. Phase 1 configuration is very robust and costs are coming down in our area, but the cost cuts into marketability Effective ventilation – we’re testing this configuration, and there's lot of other research going on too, so as a community we put it together and figure out how to go forward BTW, the ACI Retrofit Summit in 2007 concluded that our current HVAC systems won’t get us where we want to go, and they started from scratch and created some blue sky ideas. Mechanical dehumidification – high efficiency, in a tight house, with moisture suppression Minimally code-compliant closed crawl – does it work over time. Phase 1 configuration is very robust and costs are coming down in our area, but the cost cuts into marketability Effective ventilation – we’re testing this configuration, and there's lot of other research going on too, so as a community we put it together and figure out how to go forward BTW, the ACI Retrofit Summit in 2007 concluded that our current HVAC systems won’t get us where we want to go, and they started from scratch and created some blue sky ideas.