Your House: A Machine for Living

Since starting as an intern at 4CORE on January 4^th I have been on a steep learning curve in the weatherization program. I have been exposed to a wide variety of tasks and gaining on the job training in a number of different aspects of the program. I am gradually finding my niche, and feeling like a member of the 4CORE team with something to contribute.

The part of the weatherization program that I find most fascinating are the investigations of client’s homes. Over the years I have owned several different houses, but I really didn’t understand how the different systems of a house, such as heating, hot water, insulation, the flow of air and moisture (to identify just a few) all interact to form one big system that affects your comfort, health, and energy use. The first thing 4CORE does when weatherizing a home is to investigate all the systems of the house, looking for ways to improve its efficiency. This investigation is called the ‘home energy audit’. If you think of your house as a machine for living and the different systems of the house as its parts, the energy audit is the diagnostic tool used to identify the inefficient and unsafe parts.

An example of an unhealthy condition that is caused by the interaction of the house systems is something called back-drafting. Back-drafting is when combustion exhaust is pulled back into the living area of the house instead of venting up the chimney, resulting in pollution of indoor air. There are many unhealthy gases in combustion exhaust but the gas we are most concerned with is carbon monoxide. Carbon monoxide or CO, is a colorless, odorless gas that can cause sickness or death.

When a furnace starts running, it takes the chimney five minutes or more to heat up enough to start a draft, and small amounts of combustion gas may enter the living space. This temporary back-drafting is called spillage. The type of back-drafting we are more concerned with is continuous, and can be caused by the interaction of other exhaust air systems in a house. In houses with a mechanical room that has the furnace and the water heater next to each other, the stronger combustion of the furnace can potentially pull exhaust fumes out of the water heater vent, creating unhealthy levels of CO.

Another situation is when several exhaust air appliances are operating at the same time and create enough air suction in the house to draw furnace exhaust into the living area. Let’s take a house where a fire place is burning, the hot water heater is operating, the gas clothes dryer is on, and the range exhaust fan is running. All these systems are sucking air out of the house and up the vents. In a case like that there is potential for back-drafting of the furnace combustion exhaust and CO accumulation. It is these types of “worst case scenarios” that energy auditors test for, and correct if necessary.

As a footnote, it is a good idea to install combination smoke and carbon monoxide alarms in bedrooms and hallways.

Learn more about how your house works and ways to make it more energy efficient: check out the book Cut Your Energy Bill Now (150 Smart Ways To Save You Money & Make Your Home More Comfortable & Green), by Bruce Harley, 2008.

About the Author:

Tom Zajicek is interning for 4CORE through the Rocky Mountain Senior Employment in Community Program. His interest in green building and energy efficiency lead him to choose 4CORE for an internship. He is presently getting training in weatherization, including energy audits and inspections. In addition he is working on client utility data, and developing a respiratory safety program.

Tom moved to Durango two years ago from Ithaca, New York. His varied previous experience includes home building, field biology, outdoor education, and industrial roped access inspection. When not working Tom is off to the mountains, canyons and deserts of the four corners area.