There's a builder in the Northeast who has been working in the building industry since the early eighties. Since he started building custom homes, he's been using STYROFOAM rigid foam insulation over wood sheathing on every house. Even he is still amazed at the difference it makes in his customers' utility bills, energy efficiency and overall comfort.

He points to a five-year-old neighborhood where the homes average around 2,600 square feet, all have the same windows, and all use the same oil company. One of these houses, a ranch-style, uses just 900 gallons of oil a year. "A house this size should use at least 1,200 gallons each year to effectively heat it. Because we insulated the house with STYROFOAM extruded polystyrene insulation, my customer is saving about 300 gallons of oil a year," says the builder. At today's oil prices, that is a savings of almost $500 a year, or about $40 a month."

When you multiply that over a ten-year period, the savings are phenomenal.

This scenario is repeating itself in neighborhoods across the country – as more homeowners feel the pressure of rising energy costs and discover the energy-saving power of STYROFOAM insulating sheathing.

For homeowners, builders, architects and legislators alike, energy is one of the most important issues of our time. According to the U.S. Department of Housing & Urban Development, energy costs for an average family have increased 25% since 1998, and home heating and cooling bills are the largest monthly payment for families after their mortgage.

No wonder homeowners are looking for added protection against common energy drains. That's why building material manufacturers and builders themselves are concentrating on energy-efficient windows, doors, and even building homes with 2x6 studs so they can add more fiberglass insulation.

For those in the know there is an easier, more cost-effective and far more energy-efficient solution. Insulating sheathing around the entire exterior wall addresses a number of critical issues, from thermal efficiency to moisture protection.

So why isn't every new homeowner insisting, and every quality builder relying, on rigid foam insulation to improve the performance of their walls? The issue for homeowners is pretty simple – they don't know. But the issue for builders is more complex. Talk to Your Builder.

First of all, there is the perception that a home is well insulated with cavity insulation. Depending on the region, most code requires a minimum R13 to R19 batt in exterior walls. That's a good thing. But what too many builders don't realize is that wood framing and poorly insulated ducts, wiring, and plumbing make up over 25% of the exterior walls in an average home. Since cavity insulation goes between the studs and often around these fixtures, one whole side of a square home is left un-insulated. These exposed areas allow heat to escape in cold climates and intrude in warm climates – an energy-draining phenomenon called "thermal bridging."

Here's a house with OSB and R-13 batts — a good start, but look at all the thermal shorts.	Here's a house with OSB and R-13 batts, covered with 1/2" rigid foam insulated sheathing. NOW, you can see the difference adding insulated sheathing makes.
Heat loss is indicated on a scale of red, the most heat loss, to purple/blue — no heat loss.

STYROFOAM rigid foam insulation also helps protect your home from the damaging effects of moisture. In the early 1900s, The Dow Chemical Company invented a process for extruding polystyrene to achieve a closed cell foam that resists moisture. Recognizing its superior insulating properties, buoyancy and "unsinkability," it was originally adopted in 1942 by the Coast Guard for use in a six-man life raft. That was the start of many other wartime applications by the Coast Guard and Navy. Today, those same properties have found a home in your home – as insulating sheathing that resists moisture and reduces the potential for condensation in your wall where it can reduce the R-value of cavity insulation, contribute to the growth of mold and mildew, and can result in poor indoor air quality.

Here's a simple way to look at the common components of a wall, and how each one addresses energy and moisture management.

	Cavity Insulation	OSB	House Wrap	Insulating Sheathing
Energy Management
Provides R-value	11-19	0.5	0.1	1/2" = apprx. 3 1" = 5 - 6.5
Reduces Thermal Bridging
Reduces Convection Currents
Provides Continuous Coverage
Reduces Air Infiltration
Moisture Management
Protects Against Outside Moisture
Protects Against Condensation
Resists Moisture

Understanding how a wall assembly works is a quality builder's job. But it takes a thorough knowledge of science to understand how temperatures, air movement and moisture affect different materials and construction techniques (to learn more about the science behind the savings, click on Energy Management and Moisture Management). Dow has examined the science and created the one wall component no home should be without – and every homeowner should insist on for energy efficiency and moisture protection: STYROFOAM insulating sheathing.

If you're building or remodeling a home, now is the time to put the most energy efficient wall system in place. Because once that wall is constructed, clad, painted and hung with pictures, it's out of sight, out of mind. And before long you'll realize your energy bills are out of sight, too.