When choosing the right insulation system for your home you will find that you have many options. Cellulose, Fiberglass, and Spray Foam Insulation are the most commonly used types of insulation in the industry. In my attic I found that cellulose had been applied. There are both positives and negatives to using cellulose which makes choosing the right type of insulation for your home a very personal matter. Cellulose is comprised of natural materials making it very eco-friendly. When sprayed in the attic it has a tendency to settle down into the cracks and crevices creating a tighter air barrier. However, over the years, cellulose will break down and settle further reducing your R-Factor, or, thermal resistance. As it breaks down it may become dust that can be carried into your living space.
Blown fiberglass loose-fill is another option. It is made of spun glass fibers and sand or silica. It has good thermal resistance properties but does not seal completely, allowing air to pass through gaps and voids. A disadvantage of loose fill insulation is that if the insulation is handled, stepped on or compressed in any way it will not puff up to its original form. If it needs to be moved for roof repair or electrical work it will lose it's effectiveness and may need to be touched up. If using fiberglass batts, the insulation can simply moved aside and returned once the work is complete.
Spray foam insulation is a hot product right now because it offers both insulating and air sealing properties. It is a bit more expensive than either cellulose or blown fiberglass but the potential energy savings with foam insulation are significantly greater. This makes spray foam insulation the LEAST expensive option over the long term. If you are thinking about choosing spray foam as your insulation system you should use only certified spray foam contractors who have received comprehensive training in the application process. It is critical to do your homework! There are many imitation products on the market. Our business uses Icynene products because they have been at the forefront of the industry since 1986. They offer a superior product that includes a warranty. The installation of spray foam insulation can be tricky if you don't have the right ventilation system for your combustible appliances. This is an important reason to work only with certified professionals that understand how the HVAC and insulation systems work together.
Because I need the air sealing properties of spray foam insulation, I am strongly considering this as a solution. But let's think about this for a moment- I have lived in this home for about 30 years now and am anticipating a change in the next couple of years. The cost of removing the existing insulation and the addition of the proper ventilation added to the higher cost of spray foam over the next two years will significantly reduce my energy costs but will not be enough to return my investment before I put my home on the market. For my particular scenario, spray foam insulation may not be the best option to see a return on my investment for the short term. If I were planning to stay in my home longer, I would choose spray foam insulation because it is the superior product and the least expensive option as a long term solution to high energy costs.
Having ruled out foam insulation for this attic space, I still have the air sealing issues to address. Although I did not choose to spray foam my attic there are still many ways to prevent air leakage out the roof. I will address these in my next blog. But here is some food for thought. Whenever you are trying to control air leakage always start at the attic plane and work your way down!