26 Jul

Why Our System Works

Virginia Green Homes has developed a high energy efficient house named the Radiant Therma Vent ICF. It has thick polystyrene walls with self-venting exterior and a roof system exclusively for Virginia Green Homes customers. We have found that with this type of system we can heat a 5,400 square foot house for the same price of an average 1,200 square foot house. The cost for building these types of homes is comparable to the cost of a stick built house using lumber and traditional fiberglass insulations.

The wall envelope consists of either an 8’ or 10’ wall panel that is 12” thick and made of an EPA approved termite resistant EPS (expanded polystyrene). These panels have hollow vertical columns that are filled with concrete and rebar and then have a concrete attaching beam with rebar all along the top to insure added strength and stability. There are plumbing and electrical chases built in for all your pipes and wires. This system by itself is off the charts on its R Value but when we add the next two components we get amazing results. These components are the Radiant barrier automatic self-ventilating system.

Once the walls are in place we add an air vent on the outside and wrap it in a radiant barrier. Any type of wall façade can be used. We not only ventilate the walls but we connect the soffits and fascia to the roof for a complete house ventilation system. As the roof heats up hot air exits from the ridge vent and draws air from the bottom of the walls through our custom wall vent. In this way we have an entire envelope ventilating system that works as long as hot air rises. Since this happens summer, fall, winter and spring it actually insulates the house all year long.

Using this system you will have a home that has a smaller need for additional energy to cool and heat your house throughout the seasons no matter how severe the climate. The first prototype house we built used only two of these components. During one of the more severe winters for Virginia in which we had over 72” of snow the cost to heat the house was 5 cents per square foot or about $300 for one month in our prototype house of 5,400 square feet.

If we add under foundation insulation and radiant heating we increase the efficiency and comfort of this system. Once the entire envelope is built then interior walls can be built and the home can be finished to your specifications. During construction even before the A/C and heat is installed you will see about 15 degrees cooler in the summer and 15 degrees warmer in the winter due to the insulation, radiant barrier and automatic ventilation system. When guests visit you some will comment on the wide window sills which will be 12” wide. Many will wonder what your house is built of by the feeling of mass they get and how thick the walls are. They will also notice how there are no hot or cold spots and absolutely no drafts.