The homes that Michigan developer Carl Terwilliger and other health-conscious builders construct exceed the U.S. Government's most stringent energy guidelines and are made to ensure good IAQ.

The homes that Michigan developer Carl Terwilliger and other health-conscious builders construct exceed the U.S. government's most stringent energy guidelines and ensure good IAQ.


The American Lung Association is one of the leading proponents of a relatively new concept in building called "Health House." In these specially-designed homes, architects, developers, contractors and even homeowners work together to design homes that use energy more efficiently and are a healthier place to live.

This is accomplished by selecting the right location, the right building materials and in many cases, even the furnishings to control the quality of the air in the home. From the outside, the home may look like any other ordinary residential construction project. In many cases however, that is where the similarities end. Healthy Homes meet the most stringent guidelines of the U.S. Environmental Protection Agency's Energy Star program, a benchmark for energy efficiency.

In the course of constructing a "healthy" house, workers may apply special toxin-free caulking and sealers to prevent air leakage or use a special type of insulation that has minimal environmental impact and is not likely to cause problems for occupants who suffer from allergies. A major part of the Healthy House criteria is that the dwelling has satisfactory indoor air quality (IAQ). Poor ventilation is believed to be a major cause of sickness, contributing to countless days of missed work and school each year.

Carl Terwilliger is a Michigan-based developer specializing in healthier homes. A firm believer in the program, every home he constructs is designed to be more energy efficient and have fewer IAQ problems. Terwilliger says many homes constructed today have unacceptable levels of indoor air pollution, caused by everything from the choice of furnishings to a poorly-designed hvac system. So every home he builds is made to be different, with hvac systems that bring in more fresh air and help cut down on mold, mildew and dust, three of the leading culprits of poor IAQ. "People are getting sick from ¿ their homes," he said.

While many builders understand the need for "tighter," more energy-efficient housing, a side effect is that such homes are often more prone to IAQ problems, since stale, trapped air is a breeding ground for contaminants.



IAQ a priority

One of the first places Terwilliger looks to improve the IAQ of a home is with its hvac system. He often calls on Elite Mechanical of Flint, Mich. to help design and install the equipment. Owners Greg Jordan and Todd Daniels share Terwilliger's passion for healthier homes. Up to 75% of the firm's work is on homes where IAQ is a priority. It's a very different process than a traditional residential project, Jordan said.

"With any other building, you go in, you do the job and you get out," Jordan said, adding that's not the case when you're working on a healthier house. Workers may make several trips back to the home, making sure everything is properly positioned and has good air flow, he said.

The kind of hvac system installed depends on the home and needs of the home owners. In some cases, a ductless, radiant floor heating system is used. In others, the ducts are sealed. Sometimes a desiccant wheel system is installed to control humidity. Many of Terwilliger's homes use heat recovery ventilators, which remove polluted indoor air while bringing in plenty of fresh air. The warmth from the expelled indoor air is used to heat the fresh air coming into the home, allowing the system to recover up to 80% of the energy originally used to heat or cool the indoor air.

As concerns over IAQ continue to grow, Jordan predict the market for heat recovery ventilators will also increase. "One of the things you're going to see is heat recovery ventilators becoming a part of (building) codes in many cold climate regions," he said.

However, one stumbling block to the healthier home movement is price. An energy efficient, clear-air home can cost up to 5% more than a comparable home without the improvements, a surcharge Jordan admitted can be a "hard sell." But for home owners who make the investment, they are rewarded with annual utility bills up to 40% lower than their neighbors.'

The Health House movement was officially started in 1993 by the American Lung Association of Minnesota. Today, 11 other states including Michigan have adopted the program.