Passive Solar Design

There are two sides to modern housing: developing renewable energy production and reducing energy consumption. Both need to be considered and designed for either to be effective. Designing a building for maximum heat absorption in the winter, and maximum cooling strategies in the summer is called passive solar. This lowers the amount of energy needed to mechanically heat and cool the house.

Passive Solar Heating

Anything that helps to retain heat is insulation, and has an associated thermal resistance value, or R-value. By heavily insulating our house, we minimize heating and cooling needs, which saves energy year round.

Anything that helps to retain heat is insulation, and has an associated thermal resistance value, or R-value. By heavily insulating our house, we minimize heating and cooling needs, which saves energy year round.

Building the Walls This wall system is tightly sealed to prevent drafts and leaks. The wall is able to ‘breathe’ by allowing water vapor to escape, which prevents mold, while preventing water from enterng inside the wall. The highly insulated walls (R-50) and roof (R-70) are more than three times as efficient as the typical house. - Rainscreen Cladding made of slatted boards screwed into battens (red) - Battens (Gray) - The Waterproof Membrane sheds rain and snow and creates a waterproof barrier (green) After passively heating the house, we need to keep the heat inside. The walls of the ICON Solar House are rated at R-50, as opposed to the minimum R-15 in Minnesota building codes (the roof is R-70 as opposed to the minimum R-38). This rating is achieved with a carefully designed wall cavity, and closed-cell foam insulation.

Most of the windows in the ICON Solar House face south. This configuration takes advantage of the winter sun, allowing a lot of light from the sun when it is lower in the sky. Heat that builds up inside the house just from sunlight is called solar gain. Our windows are triple-glazed, meaning three layers of glass. To increase efficiency, they are coated with a low-emissivity (low-E) film to prevent heat loss. Argon gas between panes also helps to limit the transfer of heat. These windows are effective at reducing heat loss in the winter, and reducing solar gain in the summer.

High-Performing Windows Insulation helps to keep the internal climate of the house constant, which means less work for the heating and cooling systems. Windows and skylights typically have the lowest insulation value of any element in house construction. U-factor helps measure, from 0 to 1, how easily heat transfers through a material. The lower the U-factor, the better. - The triple pane windows installed have a U-factor of .25; a single pane of glass is typically rated at 1 - Two layers of low emissivity (Low-E) coating reduce radiant heat loss - Argon is a low-density gas which does not transmit heat well. It helps prevent heat transfer through the gap between panes of glass A recessed east wall with exterior horizontal slats or louvers further reduce the direct solar heat gain in summer through the large windows in the kitchen.

Daylighting

ICON Solar House windows are placed in such a way as to light activities naturally for as long as possible throughout the day. For the times when shading is preferred, a switch can be flipped to tint the windows on the east and west sides of the house. This new technology, called electrochromic window tinting, uses a small amount of electricity to create a chemical reaction which activates a tinted film, reducing the amount of sunlight passing through the glass.