See a sample payback calculation (38K PDF)

Department of Energy Fact Sheet (137K PDF)

Solarwall®

Solarwall is a proven solar air heating system comprised of metal wall cladding.  It is based on transpired solar collector technology to heat and reject heat.  Solarwall is mounted on new construction or existing exterior walls to absorb heat.  Transpired collector technology uses solar energy to preheat ventilation (outdoor) air as it is drawn into a building.  The technology is ideally suited for buildings with at least moderate ventilation requirements in sunny locations with long heating seasons.  Transpired collector technology is remarkably simple.  A dark, perforated metal wall is installed on the south-facing side of a building, creating a gap between it and the building's structural wall.  The dark-colored wall acts as a large solar collector that converts solar radiation to heat.  Fans associated with the building's ventilation system mounted at the top of the wall draw outside air through the transpired collector's perforations, and the thermal energy collected by the wall is transferred to the air passing through the holes.  The fans then distribute the heated air into the building through ducts mounted from the ceiling.  By preheating outdoor air with solar energy, the technology removes a substantial load from where it will receive the maximum exposure to direct sunlight during the fall, winter, and spring seasons.

Why buy the Solarwall system?

Solarwall heats ventilation air at substantial lower costs so you save on heating; plus, indoor air quality can be improved by bringing in more outside air.  New ventilation codes require more air to solve sick building syndrome, and Solarwall can heat this air for about the cost of running the fan.  An added benefit can be publicity or improved public image since your company is taking a leadership role in utilizing renewable energy.

What is the payback?

The payback can be immediate to a few years.  Solarwall has a better payback than many other building products such as high efficiency windows and heat recovery devices.

How much heat will Solarwall panels generate?

Each square meter (10.8 square feet) of Solarwall can generate over 500 Watts of heat (160 Btu/hr of heat per square foot of paneling).  The temperature increase of air through the system is dependent on two factors: the amount of sunlight and the volume of air passing through it.  A typical installation can raise a temperature of 30 °F to 60 °F (or 15 °C to 30 °C).  Not only does Solarwall bring in outside air, but it also helps the heated indoor air from escaping.  Any heat loss through the wall is brought back by the incoming air.

Are there any cooling benefits?

Yes, the Solarwall cladding stops sunlight from reaching the main wall and acts as a shade.  In fact, in warmer climates, applying the Solarwall cladding to the east, south, and west walls and the roof can significantly lower the cooling load of a building.

Is there any maintenance?

No!  The Solarwall cladding requires no maintenance and will last as long as any other metal cladding material.  Any fans or dampers attached to the Solarwall systems are required in any event and would have the same maintenance as an ordinary fan.

How much does it cost?

The Solarwall cladding is less expensive than many architectural is less expensive than many architectural wall materials but is slightly more expensive than metal siding.  A Solarwall system installed on new construction costs approximately $5 per square foot, where as retrofit costs approximately $10 per square foot.  All Solarwall installations receive a 10% Investment Tax Credit from the Federal Government; some states give up to a 35% Tax Credit, which makes the payback period even shorter.

Has Solarwall been tested?

The Solarwall system has probably had more testing and monitoring by the government than any other solar heating product ever known.  Canada has already spent over $500,000 on testing and field monitoring at Ford, General Motors, McDonnell Douglas and other installations.  The United States Department of Energy is also a strong advocate of Solarwall.