Few homeowners would think of insulating their house when temperatures go into the twenties but good insulation is beneficial in both winter and summer. I am taking this opportunity to discuss some pros and cons to different types of green insulation. (Ed. note: insulation install is by nature one of the more labour intensive projects within a house. Understanding the propensity for people to undertake DIY projects, please be cognizant o.f your own abilities and take on tasks that are suitable.)
Spray insulation and cellulose insulation have gained popularity in the last number of years as green products. they are considered green because of their environmentally-friendly manufacturing process or their considerable energy/CO2 savings over the life of the house they are installed in. Both will need to be installed in-situ, as opposed to prefabricated solutions such as fibreglass insulation, and that means the design and execution are vital to the positive outcome of the project.
With cellulose insulation, great strides have been made in the last few decades to increase its R-value to compete with petroleum-based fibreglass insulation. By design, cellulose insulation is the “greenest” insulation on the market, regularly using upwards of 80% recycled material in the form of shredded newspaper. I have found that the most appropriate areas in the house to install cellulose insulation are in the attic and/or floor space, since the product achieve its highest R-value when there is minimal gravity load causing settling. Vertical wall installation is possible but further material preparation is required to ensure the longevity of the product and insulation values. Typical gas/electric mechanical blowers are used to force cellulose fibres into the crevices.
Spray insulation, or spray polyurethane foam (SPF), is usually done during major renovations, since the foam has to be applied to the unexposed surface of the desired thermal break, e.g. finished concrete or exposed brickwork. While this type of insulation might seem laborious and non-DIY-friendly, I believe it has the following benefits over comparable types of insulation:
- It is not restricted by stud spacing, allowing for more intricate architectural designs to take place without the fear of inefficient or insufficient insulation.
- By design, SPF will expand into all crevices and this effectively seals the house from rodents, insects and other pests. This point is often lost on homeowners during the renovation process.
One of the things I am concerned with is the application method for SPF. There are several blowing agents used by contractors when applying it and homeowners must ask contractors to identify what type is used in their operation. Most have moved towards a water-based blowing agent which uses a chemical reaction to drive cell expansion. In addition, the components of SPF has continued to improve and offgassing in IAQ should continue to decrease; still, for individuals with a history of respiratory problems make sure to hire experienced professionals to provide proper feedback.
In the end, going green is a great concept and those who do should be applauded. However, keep in mind that, like all construction projects, there are pitfalls and homeowners must educate themselves in order to make an informed choice.
As always, all comments are welcomed.