You hear it
across the country – Who left the light on? Who left the door open? Maybe even
Who left the bathroom exhaust fan on? While there are no good reasons for
leaving lights on and doors open and the guilty party should be identified and
properly reprimanded for their crime, leaving the bathroom exhaust fan on might
not be as straight an answer as you think.
In recent
years homes have been built to tighter standards that reduce the energy usage
of the homes. These tighter standards allow the home to maintain a comfortable
living environment using the least amount of energy possible. Unfortunately a
side effect of these tighter standards is that the indoor air quality can
suffer. This is where a continuously operating exhaust fan comes in (also known
as Mechanical Ventilation). A continuously operating exhaust fan provides a way
to exhaust the stale air that builds up inside a home. The fan’s
airflow rate is set to achieve the number of air exchanges needed for your
specific home.
There are
many options for continuous operation exhaust fans but there are basically
three locations for them:
A dual speed exhaust fan in the
bathroom: This will
operate continuously at a low speed then have a high speed for when the
bathroom is in use.
A centrally located exhaust fan: This might be in a main living area
open to the rest of the house.
A kitchen range hood: This operates much like the dual
speed exhaust fan in the bathroom. A low speed provides the continuous
operation while the higher speeds provide the needed ventilation when the
kitchen is in use.
A
prerequisite for a continuously operating exhaust fan is that it is quiet. With
it always on, it is very important that the sound level does not interfere with
everyday life. Most continuously operating exhaust fans will have a sound level
that is barely noticeable.
It makes
sense – bad air out, good air in, but there are still some questions that arise:
How much energy and money is this
going to cost me? A
very valid question. Energy costs and usage are definitely hot topics, but when
you do the math, the exhaust fan is using very little of each. There are a few
factors that go into calculating the costs. The two big ones are what type of
exhaust fan you have installed and what your actual electric rate is. Using the
average United States electric rate with an ENERGY STAR® certified exhaust fan,
the cost will be approximately $.60 to $1.50 per month. Overall, a very small
price to pay to ensure the quality of the air you breath.
That can’t be good for the fan if it is running
all the time?
Not to worry,
fans that are meant for continuous operation have been tested and certified for
this type of usage.
Can I turn the fan off?
The
effectiveness of the system to provide proper Indoor Air Quality is based on it
operating continuously so it is recommended that the fan stay on. However,
there may be times when the fan needs to be turned off for servicing. Some
units will be installed with an override switch while other units will need to
be turned off at the service panel. You should contact your builder/installer
for the specific details of your installation.
