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Scott PiggEnergy Center of Wisconsin

Bruce TonnOak Ridge National Laboratory

David CarrollAPPRISE

National WAP Evaluation: Indoor Environmental Quality Field Study Findings

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Presentation Overview

Purpose

Field Study Design

Pre Weatherization Findings

Pre/Post Thermostat Behavior Findings

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PURPOSE OF THE FIELD STUDY

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Purpose in Context

Impact evaluation– Program characterization

– Energy and cost savings

– Cost effectiveness

– Non-Energy impacts Indoor environmental quality study Occupant survey

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Specific Information Goals

Carbon Monoxide – A series of measurements of different sources of CO in the home

Radon – Short term measurement of radon levels for the first floor and foundation level

Formaldehyde – Short term measurement of formaldehyde concentrations in living space

Temperature and Humidity – Longer term measurement of temperature and humidity at the central thermostat

Moisture Assessment – Visual inspection of above grade and foundation level moisture issues

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STUDY PROTOCOL

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Field Study Procedures

Sample – 88 agencies in 35 states– 325 treatment and 189 control single family homes

Time Period– Heating season field period: November 2010 - March 2011

– Cooling season field period: June 2011 - August 2011

Testing – Housing unit diagnostics and combustion appliance tests

Monitoring– Short term – 7-day radon and 7-day formaldehyde samplers

– Longer term – CO, temperature, humidity data loggers

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Field Study Sample

low

mid

high

very high

Radon stratum

Map boundaries areCensus 2000 super-PUMAs

Winter sample

Summer sample

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Field Study Visits

Visit #1 – Post Audit / PreWX (11/10 through 1/11)– PreWx diagnostic testing, instrumentation, placement of

samplers

Visit #2 – Visit #1 + 7 Days– Retrieval of radon and formaldehyde samplers / conduct

occupant survey

Visit #3 – 30 days PostWX– PostWX diagnostic testing and placement of samplers

Visit #4 – Visit #3 + 7 Days– Retrieval of radon and formaldehyde samplers and data

loggers

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PRE-WEATHERIZATION IEQ FINDINGS

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Carbon Monoxide

Heating Systems– Central fuel fired system in 75% of homes; 40%

atmospherically vented

– Small percentage with inadequate draft (< 10%)

– Small percentage with high CO production (<10%)

Water Heaters– About 20% incidence of atmospheric water heaters with

marginal drafts

– Higher incidence for measurements during warm weather

– Only 1 in 200 water heaters had high CO production

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Carbon Monoxide - continued

Ambient CO Levels– Ambient CO levels never exceeded 5 ppm for about two-

thirds of homes.

– About one in ten homes had one or more episodes of CO elevation that peaked at 20 ppm or higher prior to weatherization (the highest was ppm).

– A small percentage of homes (5%) exhibited persistent low-level CO.

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Radon

The study data indicate that 12% ±2 of single-family homes treated by the program have pre-weatherization radon levels are above the EPA guideline level of 4 pCi/l. In a few states, this fraction likely exceeds 25 percent of homes.

The study confirms that elevated radon is relatively rare in mobile homes and site-built homes in counties identified by EPA as having low radon potential.

Note: Evaluation funding is being used to remediate homes that were measured to exceed the EPA guideline.

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Formaldehyde

Formaldehyde levels were measured on the first floor above grade for a sub-sample of 145 homes

The average program home has a pre-weatherization indoor formaldehyde concentration of 14 ± 1 ppb, and most homes tested below 30 ppb.

Mobile homes may have higher formaldehyde levels than site-built homes, and weatherization may have a larger impact on these levels, but the available sample precludes solid conclusions.

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Humidity and Moisture Issues

Program homes tend to be on the dry side during the heating season: nearly half (44 ± 5%) have wintertime relative humidity below 30 percent, but ten percent or fewer (6 ± 4%) has relative humidity above 50 percent.

Fewer than 35% of foundations and 40% of above-grade spaces had observed moisture problems.

Water stains were the most common observed moisture problem in both foundations and above-grade spaces. About three in ten above-grade spaces had water stains and about one fifth of foundations had water stains.

•

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PRE/POST INDOOR TEMPERATURE FINDINGS

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Temperature – PreWX Findings

Wintertime indoor temperatures in program homes average 70.3 ± 0.5F, but range from less than 60F to more than 80F.

Households that showed evidence of practicing thermostat setback have indoor temperatures that average 3.0 ± 0.7F lower than households that do not practice setback prior to weatherization.

One quarter to one third of single-family program homes have a programmable thermostat prior to weatherization; temperatures average 1.5 ± 0.5F lower than in homes with a manual (or no) thermostat.

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PreWX Indoor Temperature

0

2

4

6

8

10

12

Pe

rce

nt o

f ho

me

s

50 55 60 65 70 75 80

Average pre-weatherization indoor temperature, FResults from 478 homes, weighted to reflect all PY08 single-family homes.Normalized to typical Dec-Feb outdoor temperature.Treatment and control groups are pooled.

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One in four households showed evidence of thermostat setback before Weatherization

% of homes with Evidence of Setback

Mean indoor temperature (F)

Overall 24% ±5 70.3 ±0.5

Manual (or no) thermostat (74 ±4%) 19% ±4 70.8 ±0.4

Programmable thermostat (26 ±4%) 34% ±9 69.2 ±0.5

3370-I22 4084-I22

Households that practice setback average 3.0 ± 0.5 F lower indoor temperature

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Pre & Post-weatherization Indoor Temperature

Measurements

Degrees F Treatment (n=292)

Control(n=168)

Mean Pre weatherization 70.2 70.7

Mean Post weatherization 70.3 70.6

Mean Change +0.14 ± 0.17 -0.13 ± 0.17

Minimum Change -6.6 -5.7

Maximum Change +5.9 +5.2

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Conclusions

This study measured a slight increase in indoor temperature associated with weatherization (0.27 degrees).

One source of the change in indoor temperature could be that weatherized homes cool more slowly when temperatures drop or thermostats are set back.

This study only addresses the potential for short-run behavior change, not the long-run.

The study findings suggest that there is no short-term “take back” effect from weatherization.