Installing real insulation in an existing house is tough. When you want to install between-the-wall fiberglass insulation, your main option is to remove the drywall. Or, if you happen to be working on a major remodeling project, the walls might already be open: no drywall yet.
When the walls are closed up and you're not interested in opening up the walls, blown-in insulation is another option that entails drilling large holes in the house exterior and pumping in loose-fill insulation.
To avoid all that mess or the uncertainty of blown-in insulation—firestops, crisscrossing wires, plaster keys, and electrical boxes inhibit the flow of the insulation—is there another option?
How about insulation paint? What is insulation paint and is it possible to paint your insulation onto the side of the house?
What Insulation Paint Is
Paint has long been used to attract or repel heat gain on houses. Black paint absorbs all available wavelengths of light and turns them into heat. White paint absorbs less light, so it heats up less. Insulation paint works differently.
Insulation paint is embedded with microscope hollow ceramic and glass spheres, or microspheres, that resist thermal conduction.
According to Thermtest Instruments, laboratory tests have shown insulation paint to have over 12 times more insulating properties than regular paint. Surfaces painted in insulation paint lose 16-percent less heat than surfaces painted with regular paint.
Nansulate, Insuladd, and Other Insulating Paints
There are several types of insulating paints, the prominent of which are Nansulate, Insuladd, Hy-Tech, and others. The way they work is that you either apply the insulating (or thermal) paint to the interior walls or you mix an additive into your existing paint. Multiple coats are recommended.
Any kind of paint coverage will add insulating properties to your house. Insulation paint adds more insulation than regular paint.
How Insulation Paint Works
Hy-Tech says that its ceramic-based paint creates a tight, thin vacuum layer that deters the passage of heat or cold. Microscopic ceramic beads no bigger than a grain of flour form this vacuum surface. Air vacuums hinder thermal properties.
That's why double-paned windows often have a vacuum layer between the panes or a gas such as argon or krypton. Argon, krypton, or air vacuums slow the molecules between the panes of glass, thus slowing the passage of heat or cold.
How Effective Is Insulation Paint?
Exactly how well insulation paint works is debatable. Different manufacturers claim different results. Hy-Tech says that since R-values can only be measured on materials 1-inch thick or greater, paint cannot legitimately be compared. They say that in their own tests, comparing their additive with one-inch thick insulation, both hindered heat transfer by 35-percent.
In the end, insulation paint will not replace a good thick layer of R-19 fiberglass between your walls. But if you have no other choice—and if your budget allows, since insulation paint and additives are expensive—you may want to try it. Insulation paint can be used in conjunction with traditional between-wall fiberglass, foam, or mineral wool insulation to increase the R-values e3ven more.
How do you apply insulation paint?
Insulation paint applies the same as conventional paint. The surface must be dry and clean. Pour the insulation paint into a lined paint tray. Roll the insulation paint onto the surface with a medium-nap paint roller cover. Apply two or more coats of insulation paint. Wash up with warm water and mild soap.
Can you convert conventional paint into insulation paint?
Yes, there are solid additives that you can pour into latex paint to give it insulating properties, similar to pre-mixed insulation paint. These additives will add another $15 to $20 per gallon of paint (in addition to the cost of the paint itself). Ceramic microsphere additives can even be mixed in with drywall compound for skim coating walls.
Is insulation paint worthwhile?
Insulation paint does work, but studies note that its cost may not be justified by the savings in energy costs. So, while insulation paint does work, it may not work as well as some users hope. Substantial energy savings will not be achieved by applying insulation paint. The U.S. Environmental Protection Agency (EPA) doesn't recommend the use of insulation paint in lieu of conventional bulk insulation products like fiberglass or foam.
Does Insulative Paint Work? Thermtest Instruments
What Are the Benefits of "Insulating Paint"? Scientific American