How Insulation Works
Understanding the way insulation impacts your home is essential for finding the right solutions
It's easy to understand how insulation works if you remember what it's like to wear a goose down jacket outside on a cold winter day. Even though your jacket is light as a feather (more accurately, many thousands of feathers), your body can stay toasty warm. That's because the feathers create millions of tiny air pockets, and air has excellent insulating value - about R-7 per inch.
Insulation works by slowing the transfer of heat, which can move in three ways: conduction, convection and radiation. For heat to travel from your body through your down jacket, it has to move by conduction through the tiny feather fibers that are in contact with each other. Heat transfer by convection happens through the air, and there are millions of miniscule air spaces between the fibers. Heat transfer by radiation is also slow, since one fiber must radiate its heat to another.
Dr. Energy Saver dealers are fully trained and certified in the workings of insulation and heat transfer in your home. Contact your local dealer for an explanation in person, and get started on energy savings today!
Understanding insulation helps you identify poor home energy performance
If you know how your home's insulation works, you can also understand what makes it malfunction and contribute to poor energy performance in a house. Here's what can go wrong:
- Voids are areas where insulation is absent. They can occur by accident, because of faulty insulation. Sometimes voids are necessary because of safety requirements. For example, an insulation void is required around a recessed "can" light that is not rated for insulation contact. Whatever the reason, insulation voids allow heat transfer by convection and radiation. Research has shown that just a 4% void in fiberglass batt insulation can result in a 50% reduction in insulation effectiveness.
- Compression compromises insulation's effectiveness because it eliminates many of the tiny trapped air pockets that provide insulation value.
- Air movement through insulation diminishes insulation effectiveness because it increases convective heat loss. To effectively slow heat transfer, the air pockets in insulation must be still. This explains how important it is to air-seal a section of your house (such as the attic, basement or main living area) prior to adding more insulation.
- Moisture decreases R-value by making the insulation more conductive and by causing settling, compression and voids.
Slowing the transfer of heat is just as important in hot weather as it is during cold weather. So even though the down jacket example focuses on insulation's role in keeping a house warm in winter, the same principles apply when it's hot outside and you want to save money on air conditioning.
Understanding insulation R-value
All insulation shares a common measuring unit known as R-value. The "R" stands for resistance to heat flow. A high R-value means greater resistance to heat flow and thus, greater insulating value. R-value is described both in R-value per inch and in total R-value.
For example, fiberglass batt insulation provides between R-3.14 per in. and R-4.3 per in. of insulating value. So a 3 ½-in.-thick fiberglass batt in a 2x4 wall cavity would provide total R-value of R-13 or so. By comparison, spray oam insulation has a higher insulation value -- around R-6 per in. The same stud cavity filled with spray foam insulation would have an R-value of R-21. Dr. Energy Saver can help you be sure you're getting the best insulation for your needs.
Get the best insulation for your home
Learn more about the different types of insulation that can be used to improve home energy savings by contacting your local Dr. Energy Saver today! We will evaluate your home and recommend the right solutions for your needs to ensure you get the results you want. Call us today to get started with an evaluation and estimate!