What is Healthy Housing?
Many people are concerned that the air they are breathing
in their home – the place they feel the safest – may actually be making them sick. Homeowners and builders
are unwilling to wait for health experts and research scientists
to offer conclusive proof of the connection between health
and indoor air quality. For builders, there are potential
liabilities in building homes that make their customers sick.
For homeowners, compromising the health and the safety of
their family is of grave concern.
The Healthy Housing approach uses healthy building materials
and other measures to enhance indoor air quality.
Three key principles for producing healthy houses have emerged
from industry research:
- Source control – By far the most
important strategy, source control means eliminating pollutants
at their source rather than trying to filter them out or
dilute them with ventilation air. Selecting low odor building
materials is an example of source control.
- Separation - Many common building materials
represent a potential health risk, but their effect on indoor
air can be minimized by sealing them away from the occupants.
Building an airtight building envelope to seal out harmful
insulation fibres is an example of separation.
- Ventilation - Continuous, balanced mechanical
ventilation reduces the buildup of contaminants and, when
combined with filtration, ensures an adequate supply of
fresh outdoor air for the occupants.
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What makes a Healthy Home?
Practical considerations for ensuring a Healthy Home follow
the guiding principles of source control, separation and ventilation:
- Select the building site carefully to
avoid power lines, agricultural spraying, vehicle exhaust
and industrial pollution – all potential sources of
indoor air contamination.
- Use clean materials such as VOC-free,
formaldehyde-free and low odor materials.
- Avoid highly aromatic, strong odor products
– even if they are natural vs. synthetic.
- Control relative humidity (RH). Mold
will grow at a RH of +60%, or during short interval surface
condensation. Dust mites will reproduce at +55%. Control
of RH can be aided by mechanical ventilation and, in some
climates, mechanical dehumidification.
- Used sealed combustion appliances, which
draw combustion air from, and mechanically exhaust the smoke
to, the outside so the risk of pollutant spills is eliminated.
- Avoid carpet. Its materials and the
adhesives used to install it can be significant sources
of chemical contamination.
- Avoid the use of pesticides or fungicides.
The toxic chemicals used to control plants, insects and
fungus are also normally toxic for humans.
- Provide continuous construction site supervision
to avoid the inadvertent use of harmful materials and reduce
the risk of contamination.
- Provide air conditioning – it
not only lowers the indoor air temperature, but also lowers
the humidity level. With less moisture in the house, the
potential for condensation, and thus the chances of mold
growth are diminished.
- Provide a low-temperature heat source,
which doesn’t burn dust – and cause air quality
problems – like a high temperature heat source does.
- Build tight. Only by minimizing air
leakage is it possible to control the quality of incoming
ventilation air and reduce the risk of contamination of
materials in the building assembly.
- Use inert sealers to seal potentially
noxious materials away from house occupants.
- Use balanced, fully ducted, mechanical ventilation.
Ventilation air can be filtered to remove outdoor contaminants
and this clean air will dilute the concentration of indoor
contaminants. Clean air should be supplied to all habitable
rooms and exhaust air should be taken from any room where
moisture or odors are generated.
- Use air filters as a second line of defense only.
It is far better to eliminate the source of contamination
than to try to filter it out of indoor air.
- Install a central vacuum system that
exhausts to the outdoors as an effective way to control
dust mites, animal dander, pollen and other particles that
are linked to health problems.
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