Today's builders, seeking
to save energy, are building
homes significantly
tighter than those built
20 or even 10 years ago.
This is admirable. But
too often neither builder
nor owner recognizes that these tight homes
need controlled ventilation.
Historically, natural air leakage (infiltration)
has ventilated our homes and controlled
moisture levels, odors, and indoor air
pollutants. The tradeoff has
been that we've had to
accept cold drafts and excessive
heat loss. To get the best
of both worlds, we need tight
houses that have controlled
ventilation systems, so that
we, and not the weather,
determine where, when, and
how much ventilation
occurs.
How Much
Ventilation Is Enough?
ASHRAE publishes ventilation
standards based on
house volume, but requiring
no less than 15 cfm air
change per hour per person.
But because