7. Use the Sun for Passive Solar Gain
- Use Solar Tempering, which uses the principles of Passive Solar without the added cost of adding thermal mass to partially heat the house. View the Solar Tempering video.
- Use higher Solar Heat Gain Co-efficient (SHGC) windows on the south side with a SHGC of about 0.4 or more, if cost-effective.
- Have approximately 50% of the window area on the south side, or have the south side windows equal 6% of the window-to-floor-area (WFA).
Use optimal roof overhangs for maximizing winter sun and ensuring summer shade to the south windows. - Calculate the BTU gain from passive solar or from solar tempering during the design phase.
- Consider installing insulated honey-comb shades, such as the Duet Architella shades from Hunter-Douglas, which may have an R-value of close to 4, in order to help keep out cold or heat depending on the season. They should be installed with minimal gaps at the edges or in tracks to be most effective; and the homeowner must be willing to close them on cold winter nights and on hot summer days.
Twelve Steps to Affordable Zero Energy Home Construction