Two of the most popular roof insulation upgrades on the market today are radiant barriers and foam insulation. Radiant barriers prevent energy loss by protecting the house from the heat, keeping heat out and acting as a blanket, keeping the home's heat inside. Foam insulation resists the heat and protects from air flow loss between the attic and living space. At the Atlanta Home Show, there was a lot of buzz about both energy-efficient solutions. Look at both to help you decide where to spend your next upgrade dollars.
What is a radiant barrier?
A radiant barrier is silver foil-type or silver paint insulation, and in the attic, it is typically installed or sprayed to the underside of the roof. The shiny surface essentially reflects the heat back, protecting the roof and attic from heat and stopping it from penetrating the living space. By blocking out the effects of the sun, it cuts down energy costs in both the summer and the winter. In the summer, it blocks out heat by reflecting. In the winter, it keeps in heat by acting as an insulation blanket stopping the heat from escaping through the roof.
Radiant barrier installation
Radiant barrier foil is a more energy-efficient option than radiant barrier spray. Foil blocks out around 97 percent of the radiant heat. Radiant spray is not as effective, blocking only 75 percent. There is only one place to apply the spray, and that is to the underside of the roof. However, foil installation has three methods. It is either applied directly to the roof deck, under the roof rafters and/or over existing insulation. The method of application is dependent on the weather and climate. Since Atlanta has warmer weather, over insulation is not recommended. For Atlanta residents, an under-roof-rafter, foil-type installation is the most effective method, as it offers two layers of protection versus the one layer of protection of the roof-deck method.
Advantages and disadvantages of radiant barriers
- Cheaper installation than foam insulation
- Deflects radiant heat
- Lowers attic temperature
- Keeps attic ductwork cooler
- Hard to install in low-pitched roofs
- Only effective against radiant heat, not convection or conduction
What is foam insulation?
Foam insulation is insulation material made of polyurethane. It comes in a spray formulation and as solid foam boards. Regardless of the type of foam insulation used, they are both more effective and energy-efficient than the traditional fiberglass and cellulose insulations. This is because they offer a greater resistance to air flow.
Types of foam insulation
Spray foam: As a spray application, it comes in either open- or closed-cell formulations. An open-cell mixture is where the cells are open with air filling the cells; this is the weaker of the two spray foams. A closed-cell formula is more dense because the tightly packed cells do not contain air; as such, it is more weather-resistant and structurally sound than the latter. Closed-cell formulations are better quality and more efficient, so they are more expensive as well. Spray foam is applied to the underside of the roof, on rafters and on the attic floor. It expands easily and can fill small gaps and voids effectively.
Solid foam or rigid foam: This comes in solid panels and is the most efficient kind of foam insulation. Unfortunately, due to the rigidity, the material is unable to expand; thus, it is not flexible nor ideal for tiny spaces.
Advantages and disadvantages of foam insulation
- Acts as an air barrier, stopping air leakage
- Reduces dust, pollen and moisture issues
- Stable R-values
- Does not sag or settle
- Spray foam expands to fill small spaces easily
- Resists conduction of heat and reduces convection
- Lowers attic temperature
- Most expensive roof insulation option
- Fire releases toxic fumes
- Not effective against radiant heat
What's the best choice?
Jamie Richmond of Canton, Ga., had his interest peaked on foam insulation. "A friend of mine just had this done, and he says his attic stayed in the 70 to 80 degree range over the summer, so for me energy savings in electricity is the main thing," he said.
However, the answer here is not the same for every homeowner. It really depends on your home, its current insulation and its energy consumption factors. How can you find out what's your best option? Get a home energy audit. A home energy audit will look at all the energy consumption in your home and pinpoint energy losses. The auditor will then tell you what priorities you should invest in when making efficiency upgrades. Of course, you will have to take your budget into consideration as well. Maybe a pricy foam insulation overhaul is just not in the budget.
Want to explore your options? Don't hesitate. Contact a roofing specialist and be on your way to energy savings.