Let’s take a look at three of the most popular insulations on the market and discuss their advantages and disadvantages.
First up, FIBERGLASS: Fiberglass has been around forever, it seems, and remains as popular as ever for its low cost and ease of use. Batts can be cut to size and is adaptable for many applications like floors, walls and ceilings. And it’s a great weekend DIY project. Blown fiberglass has the same benefits with the added feature of being able to be installed in tight, hard to reach areas. But fiberglass isn’t an air barrier, and we now know that air tight buildings are just as important—if not MORE important—than well-insulated buildings. Fiberglass batts in particular do a poor job at blocking airflow, so it’s important to understand that if fiberglass is your material of choice, you will need an air barrier material. Unless you prevent air from leaking through, insulation alone won't do much good.
CELLULOSE: Dense-packed cellulose is another popular product that’s been around awhile, for all the same reasons as fiberglass: lower cost and ease of use. It offers high thermal value and can be installed in many new and retrofit applications. As with blown insulation it’s best left to the pros unless you have the resources to install it yourself. The big downside? Cellulose resists air infiltration better than fiberglass batts, but it's still not a complete air barrier. Unless you plug the holes in your building cellulose alone will have a hard time keeping your home comfortable and your utility bills in check.
SPRAY FOAM: The Mercedes of insulation systems, spray foam offers the best of both worlds: highest thermal value available and an air barrier in one product. Recent tests have shown that spray foam is better than any other type of insulation at reducing air leakage. Plus, unlike other insulations, it retains its thermal value over time and never needs to be upgraded—making it a permanent solution. The biggest downside? Cost. Spray foam can be up to 2-3 times more expensive than fiberglass or cellulose, sometimes more depending on its application. You pay more on the front end for that permanency, but as we like to say, with spray foam you can “foam it and forget it.”
Thermal value, air barrier properties and budget are just three considerations when choosing insulation for your project. What others can you think of, and what’s most important to you? Let us know!