On average, people spend 90% of their time indoors, it is no wonder why wellness is becoming a hot topic in the construction industry. Generally, homes built using industry standard means of construction don’t take into consideration the long term wellness of the inhabitants. Radon mitigation, proper ventilation and moisture control are some the strategies that are often overlooked by builders, and as a result indoor air quality suffers. A healthy house seeks to address the wellness flaws of typical construction, which can lead to asthma, chemical sensitivity and other acute health and comfort effects.
A healthy house is designed with a focus on material selection and indoor air quality.
Building a Healthy Home
The process of building a healthy home starts early in the design phase. The right architect and builder are essential to success. Thoughtful consideration must be taken with each design decision and careful oversight during implementation of the design will lead to a home that is more durable, more efficient, and healthier. The diagram on the right shows a holistic approach to house design. The strategies shown encompass the basic tenants of an energy efficient, healthy home. A few steps during the design phase, outlined below, can have a significant effect on the outcome of a home and the wellness of it’s inhabitants.
1. Design a Good Enclosure
A good enclosure is air tight. Leaky buildings are typical for the construction industry. The misnomer that “buildings need to breathe” is is often uttered in the construction industry. An enclosure that leaks brings humid air, pollutants, allergens, dust, and pests into the enclosure and indoors. An air tight enclosure is key for superior indoor air quality and energy efficiency.
A good enclosure is properly insulated. The amount of insulation, the type of insulation, and the location of the insulation in the enclosure are important decisions and requires an analysis based on the building’s location and goals. The right amount of insulation (not too little and not too much) can help a house stay comfortable while avoiding moisture migration pitfalls.
A good enclosure controls vapor diffusion. The control of vapor diffusion within a wall enclosure is a balance of minimizing or managing wetting sources and maximizing drying potential should the wall be constructed wet, be wetted by vapor diffusion, be wetted by humid air leakage or rainwater penetration while in service. To achieve this balance the enclosure must be built with carefully chosen materials which have the proper vapor permeability. This will result in an enclosure which is not susceptible to moisture and mold damage, very durable, and maintains a high quality of indoor air.
2. Control Indoor Humidity
Indoor humidity control is an essential component of healthy home design. Humidity levels indoors should be managed to avoid high levels, which could lead to accumulation and condensation, and low levels in order to ensure comfort of the inhabitants. Excessive moisture in buildings can create favorable conditions for mold and mildew growth. In addition to a good building enclosure, a good mechanical system can keep indoor humidity balanced, creating an indoor environment that is comfortable and healthy.
3. Ventilation with Energy Recovery
A balanced ventilation system with energy recovery ensures that filtered, fresh air from the outside is used to dilute the polluted indoor air. According to the EPA there are 2 to 5 times more pollutants indoors than there are outdoors. This is because houses trap occupant generated pollutants, such as carbon dioxide, and product generated pollutants, such as volatile organic compounds. A balanced ventilation system with energy recovery ensures clean indoor air with minimal energy loss to the outside.
4. Filter Indoor Air
In addition to ventilation, superior mechanical filtration will ensure indoor air quality. Dust on people’s clothes and surfaces, as well as suspended allergens, mold spores, viruses, bacteria, chemicals, building material particles, and smoke can be filtered by mechanical means. Additionally, third-party indoor air quality testing can be completed to confirm the quality of indoor air and potentially offer further opportunity to improve the quality of the air.
5. Minimize Indoor Emissions
All of the materials that compromise the built environment can have a positive or negative effect on the people that come into contact with them. Careful consideration of the materials used for the construction of a home is important. In addition to materials, furniture selection is also very important. Some commonly used materials that are a poor choice for a healthy home include:
Vinyl – floor coverings, blinds, wall coverings, and other materials made from vinyl are a concern. Vinyl has been found to contain phthalates, lead, cadmium, brominated flame retardants, and other toxic chemicals.
Adhesives, sealants, and surface coatings – finishes, including paint, can contain numerous toxic chemicals, including volatile organic compounds (VOCs).
Engineered wood products – cabinets, flooring, doors made of engineered wood can have high levels of formaldehyde and other VOCs which off-gas for a prolonged period of time after construction.
Building insulation – specifically foam plastic insulation (spray foam) contain toxic flame retardants and other chemicals with can cause or exacerbate asthma.