Healthy Homes, Healthy Lives

Can We Design a Reliably Low-Moisture Affordable House?

Presented at The 2008 National Healthy Homes Conference Baltimore, Maryland By Melissa Malkin-Weber StudyStudy PartnersPartners

z HUD Office of Healthy Homes and Lead Hazard Control z National Institutes of Environmental Health Sciences (NIH) z UNC School of Medicine Center for Environmental Medicine, Asthma, and Lung Biology z Habitat for Humanity z Advanced Energy PresentationPresentation OverviewOverview z Origin of the study z What kind of houses and what did we do to them? z Relative Humidity z Allergens z Ventilation z Where do we look from here? HighHigh PerformancePerformance HomesHomes z 1,500+ SystemVision homes in North Carolina z Primarily affordable housing z 40% savings on heating and cooling compared to code-built CanCan thethe constructionconstruction standardstandard deliverdeliver ““healthyhealthy””?? z Program houses have promising features z Moisture Management z Combustion safety z Planned ventilation z Dilution using outdoor air z Exhaust z Can they overcome factors like… z Exhaust fan use (or not) z Building product + furniture emissions z Consumer products MethodsMethods -- StudyStudy ParticipantsParticipants z 36 homeowners in Central North Carolina z 4 Habitat Affiliates z ~ 1200 SF per house, 2-3 beds, 2 baths z Similar socioeconomics HighHigh PerformancePerformance HousesHouses -- PlusPlus

z Tight construction z Interior moisture management z Improved insulation z “Right-sized” HVAC z Outdoor air ventilation z Pressure balancing z Closed crawl space z Outdoor air intake HVACtonnage 1.00 0.00 0.25 0.50 0.75 1000 1100 2.5 TONS HVAC tonnage HVAC tonnage 2.0 TONS Non-intervention red Intervention green 1.5 TONS 1200 TotalConditionedArea 1300 1400 1500 2.5 1.5 2 TheThe CrawlCrawl SpaceSpace InterventionIntervention

Liner sealed to piers and wall, 3” termite view strip Supply air provides drying

Details found at www.crawlspaces.org RemoteRemote TemperatureTemperature RHRH andand WoodWood MoistureMoisture SensorsSensors ProjectProject MeetingsMeetings HowHow thethe crawlcrawl spacesspaces performperform –– RHRH 100

% Relative Humidity 40

20 Fixed crawl space 10 installations

0 1/1/04 3/31/04 6/29/04 9/27/04 12/26/04 3/26/05 6/24/05 9/22/05 12/21/05 3/21/06 6/19/06 9/17/06 12/16/06

Non-intervention Intervention ConclusionsConclusions AboutAbout RHRH ControlledControlled CrawlCrawl z Maintains RH below 70% -- the “mold suppressing” zone z Demonstrates suppression of moisture load from soil and outdoor air z Avoids issues common to southeast wall vented crawls z Moisture z Mold, rot z Transmission of mold to house 100 RHRH ResultsResults inin LivingLiving SpaceSpace

% Relative Humidity % Relative 40

1/1/04 3/31/04 6/29/04 9/27/0426/04 12/ Non-intervention 3/26/05 6/24/05 9/22/05Intervention 12/21/05 3/21/06 6/19/06 9/17/06 12/16/06 AverageAverage househouse RHRH andand TemperatureTemperature

a. DRY SEASON [DECEMBER 15 – MARCH 15] c. WET SEASON [MAY 15 – OCTOBER 15]

Mean St Dev Mean St Dev Mean St Dev Mean St Dev Stat Stat Return Return Return Return Return Return Return Return us us Temp Temp RH RH Temp Temp RH RH

I 70.2 2.7 37.2 5.6 I 73.7 2.4 62.3 4.4

N 69.7 3.1 38.6 4.5 N 73.4 2.1 64.3 4.4

b. SPRING SHOULDER [MARCH 15 – MAY 15] d. FALL SHOULDER [OCTOBER 15 – DECEMBER 15]

Mean St Dev Mean St Dev Mean St Dev Mean St Dev Stat Stat Return Return Return Return Return Return Return Return us us Temp Temp RH RH Temp Temp RH RH

I 71.1 2.6 46.4 4.2 I 70.8 2.7 48.0 4.8

N 69.8 2.3 50.2 4.0 N 70.1 2.2 52.3 4.3 DidDid wewe impactimpact relativerelative humidity?humidity? z Crawl space RH stayed below 70% z Expect mold suppression in crawl and reduced mold in house z House RH was not reduced z Closed crawl space + outdoor air doesn’t bring the living space to target RH z Introducing outdoor air does not dry the house z Closed crawl couples crawl RH to house z Wall-vented crawls remain coupled to outdoor RH WillWill dehmidificationdehmidification deliverdeliver RHRH <50%?<50%? z Phase 2 study preview z 22 houses z Tight envelope z Tight ducts z Intervention houses retrofitted z Mechanical dehumidification z Spot exhaust z Outdoor air intake z Upgraded filtration z “Bare bones” closed crawl space DuctedDucted DehumidifierDehumidifier GotGot (Preliminary)(Preliminary) Data?Data? DehumdifierDehumdifier ControlsControls RHRH comparedcompared toto nonnon--interventionintervention houseshouses

100 90 80 70 60 50 40

Daily Indoor %RH 30 20 10 0 03/20/2008 03/27/2008 04/03/2008 04/10/2008 04/17/2008 04/24/2008 05/01/2008 05/08/2008 05/15/2008 05/22/2008 05/29/2008 06/05/2008 06/12/2008 06/19/2008 Date AllergensAllergens z Moisture dependant allergens z House Dust Mite z Fungus (Alternaria Alternate) z No detectable difference between intervention and control groups ““Honey,Honey, DidDid YouYou PackPack TheThe DustDust Mites?Mites?””

z Moving from previous to new homes z Only bedroom floors showed significant drop in dust mite allergen levels z Most other allergen levels show no significant changes during next 18 months DustDust MiteMite AllergenAllergen LevelsLevels (Control(Control ++ InterventionIntervention Group)Group)

Median Der f1 ug/g dust (ELISA assay method) At Move-In 6 months post-move in

Living Room Floor 0.82 0.05 Living Room Couch 0.05 0.05 Bedroom Floor 0.82 0.56 Bedroom Bed 1.47 0.89 DustDust MiteMite LevelsLevels PreviousPrevious ResidenceResidence vs.vs. NewNew

Median Der f1, ug/g dust (ELISA assay method) Previous 6 months At Move-In Residence post-move in Living Room Floor 0.75 0.82 0.05 Living Room Couch 2.0 1.55 0.05

Bedroom Floor 2.59 0.82 0.56 Bedroom 165 AllergensAllergens –– NoNo ChangeChange fromfrom OldOld HomeHome toto NewNew

Median Alternaria Alternate results ug/g dust, ELISA assay method 6 months 12 months Previous At Move-In post-move post move Residence in in* Living Room 5.25 3.49 4.25 5.13 Floor Living Room 4.16 4.23 4.38 3.39 Couch Bedroo 3.73 3.64 2.88 3.35 m Floor Bedroo 2.39 2.79 2.72 3.17 m Bed AreAre wewe dilutingdiluting chemicalchemical asthmaasthma triggers?triggers?

►Groups very close in size ►Intervention had much tighter ducts (72%) ►Somewhat tighter envelope (25%) ►Intervention adds outdoor air intake (air cycler) to make up for loss of infiltration ventilation ►Add effective spot exhaust ►No source control House and Duct Tightness HOUSE PERFORMANCE VALUES BY INTERVENTION Avg Avg House Avg Duct Avg Avg duct house leakage bath 1 leakage kitchen bath 2 Status leakage leakage per ft2 exhaus per ft2 exhaust exhaust [CFM25 [CFM50 envelop t floor [CFM] [CFM] ] ] e [CFM] Interve 34 30% 862 0.25 106 58 56 ntion Non- Interve 122 104% 1142 0.31 0 38 37 ntion

% Diff 72% 25% 53% 52% (I from n/a tighter tighter higher higher N) FormaldehydeFormaldehyde samplingsampling FormaldehydeFormaldehyde LevelsLevels –– NoNo StatisticalStatistical DifferenceDifference BetweenBetween GroupsGroups

AVERAGE FORMALDEHYDE LEVELS Weight St Dev Weight St Dev Status [μg/m3] [μg/m3] [ppm] [ppm]

I 85 27 0.069 0.022

N 79 31 0.064 0.025

All 82 29 0.067 0.025 DoesDoes thethe ventilationventilation systemsystem work?work? z Tight intervention houses with outdoor air intake + timer are not higher than leakier non intervention houses z Met goal of “do no harm” – did not adversely influence the houses when tightening them z In these houses, mechanical ventilation did not solve the indoor air pollution problem PhasePhase 22 ---- VentilationVentilation z More precise z Air changes per hour z Active sampling of formaldehyde z Measure tight houses with and without outdoor air (no air cyclers) z Measure tight houses with air cyclers z Measure leakier houses without air cyclers NextNext StepsSteps

z Change Intervention Configuration z Mechanical dehumidification (<50% RH) z More affordable closed crawl configuration z Measure More Precisely z pollutants z air changes per hour z Does filtration change anything? GetGet whatwhat worksworks toto marketmarket z Market-Ready Specs z “Prescription” for a dry house www.advancedenergy.org www.healthierhomes.org [email protected] 919 857-9000 [phone] z Following are additional slides with supplementary information that will be discussed further in final report and articles 77 StepsSteps toto highhigh--performanceperformance housinghousing z Standards z Performance testing z Plan Review z Certification/Guarante z Contractor/Subcontra e ctor training z Servicing the z On-site quality control Guarantee TOTAL INTERVENTION COST*

Market cost per house Study cost per house [2003] Upgrade [2007] Materials & installation Materials & installation SystemVision $1,725 per house $1,920 - $2,100 per house

SystemVision fee $1,050 $1,050 $1.00 - $2.50 per square ~$2.50 per square foot foot Closed crawl space [$3,00 for 1200 square foot [$1,200 for 1200 square foot house] house] $170 [Spaceguard filter & Aprilaire frame] Same $200-$800 [installation] Total per house $6,145 $4,540 *Based on 1200 square foot house at lowest estimate SYSTEMVISION UPGRADE ESTIMATES* Study Market Standar estimate estimate Upgrade d per home per home [2003] [2007] 1 Proper blocking and building air tightness $75 $100 Whole-house mechanical ventilation $200 $100 2 Bath and kitchen exhaust upgrades $300 $300 Proper insulation installation $300 $150 Attic insulation increase to R-38 $100 3 Raised heel trusses $250 $250 Low-E windows $150 $150 Outdoor thermostat[s] on heat pump[s] $100 14 SEER heat pump $600 4 90% Efficient furnace with 13 SEER air $400 conditioner Proper duct sealing $100 $100 5 Pressure balance and relief $150 $150 Electric or gas water heater efficiency 6 $100 $100 upgrade 7 Carbon Monoxide detector if applicable $20 Electric package total [per home] $1,725 $2,100 Total Gas package total [per home] $1,725 $1,920 Number of homes submetered ENERGY PERFORMANCE MEASUREMENT

House Type Number in Group Number Submetered

Non-Intervention w/ 7 7 Retrofit

Non-Intervention 7 7*

Intervention 16 8

* Submetered later in the study

Baseload analysis w/out DHW and Base outliers 1200

1000

800

600

Monthly kWh Monthly 400

200

0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Baseload I Baseload NI ResultsResults1400 –– energyenergy useuse 1200 Energy use breakdown across house type

1000 800

Wh 600 ly k ly th

Mon 400 Avg Main Avg DHW Avg Comp Avg AH Avg SC Avg Base

200 0 Whole Hot water AC Compressor Air Handler Space Base House Intervention Non-Intervention Conditioning

Intervention Non-Intervention

Space conditioning saving z 13.7% total (~5.8% of total energy savings) z 3.6% June – August/ 0.8% July – September

z Intervention homes use more energy in every other category (non-space conditioning) Energy use breakdown across house type w/out outliers

1400

1200

1000

800

600 Monthly kWh Monthly 400

200

0 Avg Main Avg Base w/o DHW Avg SC Avg DHW Intervention Non-Intervention

2006-2007 Space conditioning – intervention houses use 13.7% less energy

Average energy use breakdown across all homes 100.0% 100.0% 90.0% 80.0% 70.0% 60.0% 50.0% 41.2% 36.6% 40.0% Monthly kWh Monthly 30.0% 23.5% 22.1% 20.0% 11.6% 10.0% 0.0% Main Base (w/o SC Comp DHW AH DHW) NumberNumber ofof peoplepeople perper househouse z National household

10 10

size of 2.57 8 7 6 6 6 6

people Count 4 Lev Cou Prob 2 z 2.49 for NC 1 el nt 2 3 4 5 67 2 7 0.194 z 2.51 for Wake 44 Co. 3 6 0.166 67 z 2.30 for 4 6 0.166 Raleigh 67 5 10 0.277 z 2.40 for 78 Durham Co. 6 6 0.166 67 z 2.37 for 7 1 0.027 Durham 78 MeanMean crawlcrawl conditionsconditions

a. DRY SEASON [DECEMBER 15 – MARCH c. WET SEASON [MAY 15 – OCTOBER 15] 15] Mean St Dev Mean St Dev Mean St Dev Mean St Dev Stat Stat Crawl Crawl Crawl Crawl Crawl Crawl Crawl Crawl us us Temp Temp RH RH Temp Temp RH RH I 61.4 1.6 53.6 5.8 I 71.5 2.0 66.4 4.9 N 54.9 2.3 55.4 7.4 N 72.3 1.3 83.1 4.8 b. SPRING SHOULDER [MARCH 15 – MAY d. FALL SHOULDER [OCTOBER 15 – 15] DECEMBER 15] Mean St Dev Mean St Dev Mean St Dev Mean St Dev Stat Stat Crawl Crawl Crawl Crawl Crawl Crawl Crawl Crawl us us Temp Temp RH RH Temp Temp RH RH I 64.0 1.7 61.7 4.5 I 66.3 1.5 60.2 5.2 N 61.2 1.4 64.0 7.3 N 62.2 1.8 63.8 8.6 BUILDINGBUILDING AA FRAMEWORKFRAMEWORK FORFOR HEALTHYHEALTHY HOUSINGHOUSING

ExploratoryExploratory StudyStudy ofof BasementBasement MoistureMoisture DuringDuring OperationOperation ofof ASDASD RadonRadon ControlControl SystemsSystems

Gene Fisher US Environmental Protection Agency Office of Radiation and Indoor Air

2008 National Healthy Homes Conference September 15-17, 2008 in Baltimore, MD StudyStudy OverviewOverview::

Limited,Limited, exploratoryexploratory studystudy toto demonstratedemonstrate whetherwhether activeactive soilsoil depressurizationdepressurization (ASD)(ASD) techniquestechniques cancan impactimpact moisturemoisture entryentry andand controlcontrol inin residentialresidential structuresstructures StudyStudy conductedconducted byby AuburnAuburn UniversityUniversity (SRRTC)(SRRTC) viavia aa CooperativeCooperative AgreementAgreement withwith thethe EPA,EPA, awardedawarded inin JulyJuly 20042004 ThreeThree houseshouses withwith unfinishedunfinished basementsbasements werewere studiedstudied forfor anan 1818--monthmonth periodperiod (Harrisburg,(Harrisburg, PA)PA)

2 StudyStudy TeamTeam MembersMembers Auburn University: Jan Carrington - Administration Jack Hughes - Mitigation and Technical Specialist Brad Turk - Principal Investigator

PA Department of Environmental Protection (PA DEP): Mike Pyles - Radon Program Manager Bob Lewis - Field Support Matt Shields - Field Support Private Contractor: Bob Myers - PA Certified Radon Mitigator Margaret Menache – UNM, Statistician US EPA: Gene Fisher - Project Officer Patsy Brooks - Region 4 Radon Coordinator Susie Shimek - Past EPA Radon Team Leader Phil Jalbert – EPA Radon Team Leader

3 ActiveActive SoilSoil DepressurizationDepressurization

ReducesReduces radonradon entryentry byby mechanicallymechanically creatingcreating aa suctionsuction beneathbeneath thethe homehome’’ss foundationfoundation thatthat isis strongerstronger thanthan thethe suctionsuction appliedapplied byby thethe homehome CollectsCollects radonradon priorprior toto entryentry andand exhaustsexhausts toto aa safesafe locationlocation outsideoutside thethe homehome SpecificSpecific applicationapplication dependsdepends onon foundationfoundation typetype

4 SubSub--SlabSlab DepressurizationDepressurization (SSD)(SSD)

Discharge SuctionSuction createdcreated byby fanfan drawsdraws Attic Fan radonradon fromfrom Depressurization beneathbeneath thethe Piping System concreteconcrete slabslab andand safelysafely ventsvents radonradon outdoorsoutdoors

5 BlockBlock WallWall DepressurizationDepressurization

MayMay bebe necessary,necessary, ifif aa subsub--slabslab systemsystem isis unableunable toto drawdraw radonradon downdown throughthrough thethe blockblock toto thethe subsub-- slabslab area.area. SystemSystem maymay requirerequire suctionsuction onon moremore thanthan oneone wall.wall.

6 ActiveActive SystemsSystems

7 Residential SSD Systems

8 EventsEvents LeadingLeading UpUp toto thethe StudyStudy

AnecdotalAnecdotal informationinformation datingdating fromfrom 19861986

Literature/modelLiterature/model searchsearch inin 20022002

ExpertsExperts meetingmeeting inin JuneJune 20032003

CooperativeCooperative AgreementAgreement JulyJuly 14,14, 20042004

9 AccomplishmentsAccomplishments -- FirstFirst YearYear

Developed house selection criteria

Developed conceptual model

Measurement protocols

Conducted walk-through visits

Study houses selected – criteria compromised

Instrumented three PA houses (May, July 2005)

Mitigated three PA houses (July, September 2005)

10 StudyStudy HouseHouse #1#1 (PA01)(PA01)

11 StudyStudy HouseHouse #2#2 (PA02)(PA02)

12 StudyStudy HouseHouse #3#3 (PA03)(PA03)

13 TestsTests && MeasurementsMeasurements Approx. 115 Parameters are Recorded Every Hour at Each of 3 Houses

Air Flow In & Out of Basement Outdoors, Upstairs, and Soil • PFT Tracer Gas Ventilation Tests* • Air Leakage Area • Differential Pressures • Effective Resistances (floor, soil) • Soil Gas/Radon/Moisture Entry Potentials • Radon Concentrations • ASD Velocity Pressures/Flow • ASD Static Pressures • Wind Direction and Speed • HVAC On-time

Temperature & Water Vapor Content of Air Outdoor, Basement, Microclimate, Upstairs, Soil, ASD • Temperature & Heated RH

Moisture Storage & Diffusion Walls, Floors, Wood Framing • Moisture Content Pins • Wood Block Moisture Sensor • Heated RH * Lawrence Berkeley National Laboratories (LBNL) multi-zone ventilation measurements

14 15 16 MeasurementMeasurement ClustersClusters

Key measurement locations of temp/RH/moist – 4 wall locations – 2 to 3 slab floor locations Temp, RH, and moisture content at different depths in wall and floor materials – Poured wall & block wall configurations differed Also Delta P (all) and Radon (at 2 clusters)

17 18 19 20 21 22 Multi-tracer Interzonal Flow & Ventilation System

23 24 25 26 27 28 29 ActivitiesActivities (2006(2006--2007)2007)::

Comparison of dehumidifier and ASD performance and energy use in one house Study ASD configurations more similar to typical radon control installations Continue to monitor response of moisture levels during overlapping seasons Evaluate alternate less intensive measurement protocol using handheld instruments Houses were decommissioned in January 2007

30 StudyStudy ReportReport:: ExploratoryExploratory StudyStudy ofof BasementBasement MoistureMoisture DuringDuring OperationOperation ofof ASDASD RadonRadon ControlControl SystemsSystems SeeSee Website:Website: www.epa.gov/radon/pubs/index.htmlwww.epa.gov/radon/pubs/index.html

Appendix A - Report on Experts Meeting/Recommendations Appendix B - Forms, Logs, and Checklists Appendix C - House Selection Criteria Appendix D - ASD System Diagnostics, Design, Description Appendix E – Monitoring/Testing Techniques, Instrumentation Appendix F - Description of Electronic Data Files Appendix G - Conceptual Model: Impact of ASD Operation on Basement Moisture Conditions Appendix H - Summary of 14-Day Mean Daily Moisture Changes Appendix I - Summaries of Handheld Surface Moisture Data

31 ActivitiesActivities (2007(2007--2008)2008)::

Analyze data to further establish relationships between inside and outside moisture levels (in progress) Create statistical model relating indoor moisture levels to outdoor moisture levels (in progress) Examine more closely ASD impact on basement pressures and moisture discharge Extend analysis of the sources of air and moisture in the ASD exhaust

32 Exploratory Study of Basement Moisture During Operation of ASD Radon Control Systems: Results & Analysis Bradley Turk Environmental Building Sciences, Inc. - Las Vegas, New Mexico, USA

U.S. EPA Indoor Environments Division -- Project Sponsor Eugene Fisher, Patsy Brooks, Phil Jalbert, Susie Shimek

Auburn University SRRTC Jack Hughes

PA Department of Environmental Protection (PA DEP) Robert Lewis, Michael Pyles, Matthew Shields

University of Waterloo (Ontario, Canada) John Straube Conceptual Model

• Question: How would ASD affect moisture in basements?

• Premise: ASD could alter air flow patterns into, within, and out of building Conceptual Model 3 classes of air flow

Class 1 ASD Class 2 ASD Class 3 ASD Operation Operation Operation

Outdoor Air Outdoor Air Upper Level Air Outdoor Air (drier than (drier than Upper Level Air (drier than Upper Level Air basement air) basement air) basement air) 1a)

2a)

2b) 2c) 1b) 2d)

- Moisture in buildings has many sources - Air flows occur concurrently & can vary over time - Upstairs & outdoors air can add/remove large amounts of moisture in basement Estimates of Moisture Contribution

• Air flows to basement from outdoors, 1st floor, and soil can deliver > 25 kg/day • 50 cfm at 11g/kg entering air

• Diffusion through poured concrete walls and floors is typically < 2 kg/day (2 liter/day, 0.5 gal/day, 1.4 g/min) • 1500 ft2 basement • Diffusion becomes important when: » ventilation rates are low » more permeable materials (block walls) ASD System Characteristics Static P (Pa) Total Flow (cfm) PA01: 69-110 62-85 1- interior drain tile loop* 1- center of slab PA02: 190-210 90-140 1- interior drain tile loop* 1- sump/ext. drain tile loop PA03: 74 87-180 1- slab* 2- block wall

-- Systems were initially operated to be more robust than typical installations, then later reconfigured to be more typical*. Indoor Radon • Radon is dramatically reduced • Usually, the dominant source of radon is the soil

64 60 59.3 56 51.9 52 A = Off, Baseline 48 B = Seal Wall/Floor Joint 44 C = Full ASD, All Pipes Open 40 D = Single Subslab ASD Pipe 36 32

28 EPA's Radon Mitigation Action Level 24 4 pCi/L 20 16.1 Average Basment (pCi/L) Radon 16 13.2 12 8

4 1.7 0.4 0.7 0.6 0.9 0.3 0.5 0 (1809) (1119) (1969) (2468) (11150 (4359) (3764) (1199) (4508) (2946) (1264) < Hrs Monitored AA+BCC+BD+BA) C D ACD PA01 PA02 PA03 Measured Changes in Air Flow Patterns Caused by ASD (PA02)

Air Flows (cfm)

35 12 11 23

Winter ASD On 20 17 ASD Off 5 38 62 (ASD + Exfiltration) 16 2.5 47

Multi-tracer sources and sample analysis provided by David Faulkner & Bill Fisk, LBNL In these 3 houses, moisture in basement air tracks outdoor air moisture

Basement RH Out Hum Ratio ASD Full (On/Off) 80 ASD Single-Pipe (On/Off) 25

70 20 60

50 15 ty Ratio (g/kg) 40

10 30 Basement Air RH (%) 20 5 10 Outdoor Air Humidi

0 0

5 6 6 6 6 7 /05 /0 0 /06 /06 0 /06 /06 /06 /0 /06 0 /06 /0 5 4 4/05 2 4 2 2 0 0/06 /9 /1 /1 1 /1 /13 /1 1 2 1/8 1 1/13/ 2 3/1 4/13/ 5 6/1 7/1 8/11 9 11/9/ 1 10 1 12/ 10/ Basement-Source Air Relative Moisture Index PA02

Soil Î 1.0 r e Upstairs ry D Outdoor e 0.5 rc u o S e s a b 0.0 H A r /) e e t rc e u -0.5 o W s e rc H u A o -e S s -1.0 a b Í H (A -1.5

-2.0 Relative Drying/Wetting Potential PA02

(AHbase-AH source) /AHbase) x FlowIntoBase

0.45 0.4 Soil Upstairs 0.3 Outdoor

) 0.2 in m Î / g 3 n 0.1 i (m ry l D a ti n 0.0 te o g P in t g -0.1 e in W ry D Í -0.2

-0.3

-0.4 Net Convective Moisture Flow PA02

Soil-to-Base Up-to-Base 10 Out-to-Base ) 8 Î in in a /m 6 G g ( s 4 s o 2 Out-to-Base /L Up-to-Base in 0 Soil-to-Base a G -2 e s r s tu -4 o is L o -6 Í M -8 -10 Wall Moisture -- PA02

120

100

40 Interior Core

Block Wall Equilibrium RH (%) RH Equilibrium Wall Block Thru Wall 20 ASD Full (On/Off) ASD Single-Pipe (On/Off) 0

. . 6 6 6 . 6 7 .. .. 0 /06 0 /06 0 /06 . /0 0 /1 3/ 4 3/ 2 2/ 0 /9/06 /9 /8/ 2 1 /1 1 /1 1 /11/06 /1 1 2 1 10/1 11/1... 1 1/ 2/12/06 3 4/ 5/13/06 6 7/ 8 9 10/1. 1 1 Mean RH -- PA02 Dec 2005 -- Jan 2007 100 ASD Off 91.3 91.0 90.7

ASD Full On 90.3 89.8 88.9 88.3

90 87.2 87.1

ASD Single-Pipe Off 86.7 85.6 83.9

ASD Single-Pipe On 83.2 82.5 80.6 Summer -- ASD Off 80.2 80 Summer -- ASD Full On 74.1 74.1 73.9

70 68.1 61.8 60.9 60.4 58.3

60 57.5 56.4

50 48.7 41.6 41.0 40 33.8

Mean RelativeMean Humidity (%) 30

0 Interior Core Top Middle p<.0001 p<.0001 p<.0001 p<.0001 p<.0001

p<.0001 p<.0001 p<.0001 p<.0001 p<.0001

p=0.1888 p<.0001 p<.0001 p=0.3333 p=0.3958 Basement Air Block Walls Slab Floor Second 7 days of 14-day, or longer, cycling periods Autoregression on 1st Seven Days of Each Cycle PA02 Basement Air

80 25

60 )

50 15

10 30 Basement Air RH (%) Air Basement

20 Measured RH (g/kg Ratio Humidity Air Outdoor Regress Line - ASD On 5 Regress Line - ASD Off 10 ASD (On/Off)

0 0

6 /0 6/9/06 7/9/06 8/7/06 9/6/06 1/3/07 10/15/05 11/13/05 12/13/05 1/12/06 2/10/06 3/12/06 4/11/06 5/10/06 10/6/06 11/4 12/4/06 Mean Daily Change in RH -- PA02 Oct 2005 -- Jan 2007

3.0 AS D Of f 2.22 ASD Full On 2.0 ASD Single-Pipe On Summer -- ASD Off 1.18 Summer -- ASD Full On 0.87 0.86 1.0 Summer -- ASD Single-Pipe On

0.27 0.13 0.0 -0.13 -0.11 -0.23 -0.21 -0.37

-1.0 -0.93 -1.24 -1.24

-2.0 -1.76 -2.00

Mean Change Daily in Relative Humidity (%) -2.44 -2.47

-3.0 p<.0001 p=0.1975 p<.0001 p<.0001 p<.0001 p<.0001 9/13>0 9/10<0 3/3>0 1/2<0 76/78>0 60/60<0 17/18>0 12/12<0 49/65>0 43/50<0 13/15>0 8/10<0

p=0.0003 p=0.3253 p<.0001 p<.0001 p<.0001 p=0.0020 3/3<0 1/1<0 15/15<0 6/6<0 8/12<0 4/5<0 -4.0 Basement Air Block Walls Slab Floor

Surface & Joist Measurements vs. Embedded Sensors (PA02)

100 12

10 80

70 8 60

50 6

Wall Sensor Interior (W3) 4 30 Floor Sensor Top (A5) Surface & Joist Avg Moist Content (%) Content Moist Avg & Joist Surface Wall &Sensor Wall Floor RH Equilibrium (%) 20 Wall Surface Average 2 Floor Surface Average 10 Ceiling Joist Average

0 0 5 05 /05 0 06 06 06 06 /06 /05 3 1 12/ 12 1 /13/05 /14/ 17/ 17/ 18/06 19/06 19/ /20/ /2 0/ 7/12/05 8/ 9/ 1 11 12 1/14/06 2/14/06 3/ 4/ 5/18/06 6/ 7/ 8/ 9/19/06 10/20/06 11 12 Dehumidifier & Condensate Monitoring Dehumidifier Impact in Air & Wall vs. ASD PA03

100 70

90 60 80

70 50

60 40 50 Dehumid On ASD (On/ Off) 30 40 Bs m t Air RH Wall Co re RH (W9) Basement Air Air RH (%) Basement 30 20 Bsmt Air Radon 20 Basement Air Radon (pCi/L) 10 10

0 0

6 6 6 6 6 0 0 /06 /06 /06 0 0 0 /06 3/ 3 /2 2 0/ 0/ /9 /14/ 4/ 3/06 /1 6 /2 /12/ 06 8/1/06 21/ 1 3 4/2 5 6 7 8/ 9/1 9/3 10/20/06 1 Moisture Extracted During Cycles PA03

Slab ASD Front Wall BWD Back Wall BWD 35 Total ASD Dehumidifier 120 30 ASD Full (On/Off) ASD Single-Pipe (On/Off) ) y 100 a ) d 25 y l/ a a /d g L ( ( 80 e re 20 r tu tu is is o o M 60 M d 15 d te te c c a a tr tr x 40 x E 10 E

5 20

0 0 Average Moisture Extraction

(gal/day)

House Full Single % ASD Exh. ID System Pipe Dehumid. from Base. PA01 13 10 -- 46

PA02 15 13 -- 72

PA03 19 11 1-4 72 Est. Additional Yearly Energy Costs

House ID/ Out-1st Flr Add. Add. Radon Total Add. Season Flow Heat Cool Fan Elec. Cost Change Cost Cost Cost ($) ($) (cfm) ($) ($)

PA01 3.3 - 3.9 10 2 70 83

PA02 22 - 41 60 24 70 154

PA03 30 - 63 80 41 70 191

Dehumid. 180 Summary for These Houses • During non-summer months ASD caused significant reductions in basement moisture (and likely reduces summer dehumidification) • ASD robustly controls radon; may affect IAQ and energy use • Moisture Sources: Soil gas minor contributor, outdoor air moisture appears to dominate ASD effects • Moisture Drying: Upstairs air, outdoor air (winter) • ASD impact on moisture related to many factors: air leakage from outdoors, upstairs, and soil, HVAC systems, outdoor conditions, soil types Summary for These Houses (cont)

• Moisture performance during continuous, long- term operation not studied • Changes in air flow patterns consistent with model • ASD can significantly increase outdoor air ventilation by exhaust: pros and cons • At 1 house: dehumidifier more effective controlling indoor air RH, but ASD also reduced wall moisture • Dehumidifier extracted approximately 8% to 25% of the moisture removed by the ASD system Conclusion ASD Can Have Significant Moisture Impact, But . . .

• ASD designed for radon control may not be optimal for all moisture concerns

• Uncontrolled, additional ventilation may not be desirable

• ASD impact on moisture may not be the same for different climates, seasons, and house construction and systems Future Research Needs • Results of this study of 3 houses insufficient for national design & policy guidance • Research framework: –Enhance conceptual model: predict performance in other climates, house construction & soil types –Develop simplified field evaluation, test and measurement protocols –Field validation studies in other regions of US –Monitor microclimate & moisture in wall assemblies (e.g., frame & gypsum board) during ASD –Examine system performance during continuous long-term operation Get the Full Report

http://www.epa.gov/radon/pubs/index.html

(about the 6th publication on the list)