Ventilation and Moisture
Ventilation and moisture control are critical aspects
of operating any existing home, and the design and construction of new
homes. These publications, web sites and frequently asked questions
should help you address concerns and access resources to achieve good
indoor air quality, reduce and avoid mold and moisture problems, and
better understand the relationships of energy, ventilation and moisture
in our homes and buildings.
The first web site listed in each section is a good place to
find general information and access broad aspects of ventilation
or moisture concerns and resources. The technical detail increases as
you go down the list.
Each of the publications can be downloaded and printed for your
use. The first three in each section are good starting points
for general information and addressing the most common consumer issues
and questions. Further down each list the information in the publications
becomes more technical and detailed.
Ventilation Web
Sites
Ventilation for Homes
http://www.epa.gov/iaq/homes/hip-ventilation.html
Home Ventilation Options for Home Builders
http://oikos.com/esb/39/VentOpt.html
Addressing Indoor Environmental Concerns During Remodeling
http://www.epa.gov/iaq/homes/hip-combustion.html
Buliding Science Basics
http://www.healthhouse.org/iaq/buildingscience.htm
Buliding Science Corporation-Mechanical Systems
http://www.healthhouse.org/iaq/buildingscience.htm
Ventilation
Publications List - 9
Consumer Fact Sheets
Whole House Ventilation Systems 26458.pdf
Improved control of air quality
Technology Fact Sheet
Building Technologies Program
Office of Energy Efficiency and Renewable Energy US DOE
Spot Ventilation 26466.pdf
Source control to improve indoor air quality
Technology Fact Sheet
Building Technologies Program
Office of Energy Efficiency and Renewable Energy US DOE
Homeowners Guide to Ventilation guide.pdf
NY State Energy Research and Development Authority
518-862-1090
www.nyserda.org
Home Ventilation & Indoor Air Quality HVI_Ventilation_Guide.pdf
Home Ventilating Institute
The Home Ventilating Institute(HVI), a division of the Air Movementand Control Association (AMCA), is a
nonprofit association representing 58 companies that sell HVI Certified home ventilating products.
Bathroom Ventilation Guidelines BathroomVentilationforHVI.pdf
Home Ventilating Institute
The Home Ventilating Institute(HVI), a division of the Air Movementand Control Association (AMCA), is a
nonprofit association representing 58 companies that sell HVI Certified home ventilating products.
Technical Articles and Papers
Recommended Ventilation Strategies for Energy - Efficient Production Home LBNL-40378.pdf
Judy A. Roberson
Richard E. Brown
Jonathan G. Koomey
Steve E. Greenberg
Energy Analysis Department
Environmental Energy Technologies Division
Ernest Orlando Lawrence Berkeley National Laboratory
University of California
Berkeley CA 94720, USA
This report evaluates residential ventilation systems for the U.S. Environmental Protection
Agency's (EPA's) ENERGY STAR® Homes program and recommends mechanical ventilation
strategies for new, low-infiltration, energy-efficient, single-family, ENERGY STAR production
(site-built tract) homes in four climates: cold, mixed (cold and hot), hot humid, and hot arid.
Residential Ventilation and Energy Characteristics resventw_fm5.pdf
Max Sherman
Nance Matson
Energy Performance of Buildings Group
Energy and Environment Division
Lawrence Berkeley Laboratory
University of California
Berkeley, California
This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building
Technology of the U.S. Department of Energy under contract no. DE-AC03-76SF00098
The Use of Blower Door Data BlowerDoor.pdf
Max Sherman
Energy Performance of Buildings Group
Energy and Environment Division
Lawrence Berkeley Laboratory
University of California
Berkeley, California
This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office
of Building Technology of the U.S. Department of Energy under contract no. DE-AC03-76SF00098.
Retrofitting Ventilation into Low-Rise Housing 00-144-e.pdf
This Research Highlights fact sheet is one of a wide
variety of housing-related publications produced by CMHC.
For a complete list of Research Highlights, or for more
information on CMHC housing research and information,
please contact:
The Canadian Housing Information Centre
Canada Mortgage and Housing Corporation
700 Montreal Road
Ottawa, ON K1A 0P7
Telephone: 1 800 668-2642
FAX: 1 800 245-9274
Moisture
Web sites
Mold Resources - US EPA
http://www.epa.gov/iaq/molds/moldresources.html
New York City Department of Health & Mental Hygiene
Bureau of Environmental & Occupational Disease Epidemiology
Guidelines on Assessment and Remediation of Fungi in Indoor Environments
http://www.ci.nyc.ny.us/html/doh/html/epi/moldrpt1.html
Molds in the Environment
Air Pollution and Respiratory Health Branch
National Center for Environmental Health
Centers for Disease Control and Prevention
http://www.cdc.gov/nceh/airpollution/mold/moldfacts.htm
Moisture Publications
- 9
Consumer Fact Sheets
Controlling Mold Growth in the Home mf2141.pdf
Marilyn Bode and
Deanna Munson, Kansas State University, September 1995.
Kansas State University Agricultural Experiment Station and Cooperative
Extension Service
MF-2141 September 1995
A Brief Guide to Mold, Moisture and Your Home moldguide.pdf
U.S. Environmental Protection Agency
Office of Air and Radiation
Indoor Environments Division
1200 Pennsylvania Avenue
Mailcode: 6609J
Washington, DC 20460
www.epa.gov/iaq
Moisture Audit of Residential Structures HH_Moist_Audit.PDF
Prepared by Housemender Inc. for Environmental Health Watch
www.ehw.org
Technical Articles and Papers
Mold: Causes, Health Effects and Clean-Up mold_causes.pdf
Joseph Lstiburek, Ph.D., P.Eng.
Nathan Yost, MD
Terry Brennan, MS
2002
Building Science Corporation
70 Main Street, Westford, MA 01886
(978) 589-5100 fax: (978) 589-5103
What You Need To Know About Mold mold_need_to_know.pdf
Nathan Yost, MD
Joseph Lstiburek, Ph.D, P.Eng.
Terry Brennan, MS
2002
Building Science Corporation
70 Main Street, Westford, MA 01886
(978) 589-5100 fax: (978) 589-5103
Mold Remediation in Occupied Homes mold_remediation.pdf
Nathan Yost, MD
Joseph Lstiburek, Ph.D, P.Eng.
Terry Brennan, MS 2002
Building Science Corporation
70 Main Street, Westford, MA 01886
(978) 589-5100 fax: (978) 589-5103
Mold Testing mold_testing.pdf
Nathan Yost, MD
Joseph Lstiburek, Ph.D, P.Eng.
Terry Brennan, MS 2002
Building Science Corporation
70 Main Street, Westford, MA 01886
(978) 589-5100 fax: (978) 589-5103
Managing Water Infiltration into Buildings Managing Water…Buildings.doc
A Systematized Approach for Remediating Water Problems
in Buildings due to Floods, Roof Leaks, Potable Water
Leaks, Sewage Backup, Steam Leaks and Groundwater
Infiltration
University of Minnesota, Environmental Health and Safety Division at
612/626-6002.
Evidence Based Statements Mold Health Effects ACOEM.doc
Adverse Human Health Effects Associated with Molds in the Indoor Environment
Copyright © 2002 American College of Occupational and Environmental Medicine
FAQs
How do I know how tight to build a new house?
The "tightness" of a home is measured by how many
times an hour the air in the house is completely
replaced with outside air-air changes per hour
(ACH). The American Society of Heating,
Refrigerating, and Air-Conditioning Engineers
(ASHRAE) recommends a minimum of .35 ACH.
The actual air-leakage rate changes based on outside
temperature, wind speed, appliance operation, and
other factors.
One simple way to estimate the tightness of a home
is with a blower door. A blower door is a calibrated
fan, temporarily installed in an outside door, which
de-pressurizes the home. The leakage rate is measured
with the fan maintaining a pressure difference
between the inside and outside. The average natural
leakage rate is then estimated.
Home energy raters have been trained and certified
to perform home energy ratings (HERs) that include
an evaluation of a home's air tightness. Visit the listed
Web sites to learn more about home energy ratings
and to find a list of certified raters that can perform
a blower door test.
See also:
www.ratingsalliance.org/raters.htm
www.kansasbuildingscience.com/
www.natresnet.org/herseems/default.htm
What is the recommended ventilation approach for a new house?
The best approach would provide a controlled and
appropriate amount of outside air, distributed evenly
throughout the conditioned space of the house,
enhancing comfort, combustion safety, building
durability, and indoor air quality. The approach
selected should be based on actual knowledge of the
building's air tightness, as assessed by a blower door
test, or developed by the experience and performance
testing of past construction. The system design
should consider the minimum ASHRAE recommendation
of .35 air changes per hour (ACH) or the
expected occupancy times of 15 cubic feet per
minute (CFM). For example, four people x 15CFM
= 60 CFM.
There are four options for ventilation of a new
house. The first is "natural ventilation," or an uncontrolled
approach relying on various air pressure-driving
forces to move air through leaks in the building.
This does nothing to provide equal or needed air distribution
throughout the house. Blower door tests
have shown that many homes are inadequately ventilated
or, conversely, have excessive leakage and related
indoor air quality problems.
A second option is an exhaust-only system. This consists
of a central fan or distributed fans exhausting air
out of the house. As the fan(s) removes air from the
house, fresh air enters through inherent air leaks in
the building or small, passive air vents can be strategically
placed in several rooms of the house. A key
concern with this approach is the importance of
using sealed, power-vented, or direct-vented combustion
appliances so air is not drawn through these systems,
potentially affecting their safe operation. It is
also important that air not be drawn in from garages,
crawl spaces, or other spaces with pollutant sources
that might affect indoor air quality.
A third option is integration with the central heating/
cooling system. This approach would typically
use a 5- to 8-inch insulated outside air duct connected
to the return side-duct plenum of the central airdistribution
system, using either the furnace or small
duct fan to provide the designed quantity of outside
air. A balancing damper should be installed in the
outside air duct to adjust the air flow upon system
startup, and provisions should be made to filter the
outside air prior to its entering the central system.
The fourth option is an integrated mechanical ventilation
system with an energy-recovery ventilation
unit. When heating and cooling is active, the ventilation
air would be distributed throughout the house
via the central fan. The central fan recycling system
would make sure the ventilation air was distributed
when there was no demand for heating or cooling.
The purpose of the ERV unit would be to lower the
cost of conditioning ventilation air, and, in winter, to
recover some interior-generated moisture to keep the
house from being too dry.
The control strategy (fan timers, humidity sensors, or
other air quality sensors) used to run the ventilation
system selected is an important consideration. It
should combine the need for automatic controls,
assuring continuous ventilation, and allow for manual
override when needed.
See also:
oikos.com/esb/39/VentOpt.html
www.healthhouse.org/iaq/buildingscience.htm
www.buildingscience.com/resources/mechanical/
What is the recommended relative humidity for a house, and how is that related to mold and mildew growth?
Keeping home relative humidity between 30 and 55
percent will do the most to reduce the potential for
ill-health effects for occupants, as indicated by the
chart below. This is done by controlling sources of
moisture, and venting moisture from inside when it
is generated by washing, cooking, and other common
activities. Although mold and mildew exist in
many homes, they can present problems when
allowed to persist or spread due to higher humidity,
lack of ventilation, or unclean conditions.
See also:
www.epa.gov/iaq/molds/moldguide.html
