Ken's Weekly E-Tip: Sealing vs. Ventilation
Most energy experts highly recommend sealing homes as airtight as possible. But we can over seal our homes and make them unsafe. So what is a person to do? Here are some ideas to help members understand this dilemma.
Most home (even new construction) contain leak areas which provide opportunities for air infiltration such as penetrations into attic areas, basement ban joist seals, as well as plumbing and electrical penetrations. A typical home leaks, on average, about half of its air every hour. This is similar to having a window open all day, every day. Caulking and foam sealants will retard air infiltration in these areas.
It is possible to button up a home so tight that indoor air quality problems, pollutants or moisture build up can occur.
So how do we know we have done the job correctly?
Blower Door Testing
The best way to inspect how well a home is sealed is to hire a contractor or energy auditor to conduct a blower door test. This is accomplished with a door that uses a powerful fan to measure air infiltration rate.
The professional will be able to measure how much air is leaking and where major concern areas need attention. Homes are retested after sealing is completed and possible mechanical ventilation is recommended as needed. Mechanical ventilation is consistent and can be controlled, as opposed to "natural" ventilation from air leaks.
Exhaust ventilation - Fans that pull air out of your home, which increases infiltration from the outside. These are typically above a range or in a bathroom ceiling. These fans generally have to be turned on manually. Some can be installed with condensation or humidity sensors that are activated when higher moisture is sensed in the air surrounding them.
Supply ventilation - Fans bring outside air into your home.
Energy recovery ventilation - Fans combined with heat exchangers that modulate the temperature and humidity of incoming air.
Determining which method is best for you will depend on your home's needs, your budget and your climate.
The bottom line: "Seal tight, and ventilate right."
Earn $50 Bill Credit
Let CEC install a load control device on your own electric water heater and earn a $50 one-time bill credit and a monthly $2.50 bill credit. Call 800-521-0570 x2195 to learn more. Members having a water heater installed by the cooperative are not eligible for the credits.
Twitter and Load Control
Participants in our load control program for electric heat and water heaters can find out when and how long control periods are predicted by logging onto www.central.coop and clicking our Twitter logo. Please remember these are only predictions and actual times may vary.
If you have any ideas for future E-Tip topics, email me at firstname.lastname@example.org.