Passive Solar Home Building Tips
You probably already live in a passive solar home and don’t even know it. The good news is that your home’s windows, walls and floors collect, store and distribute solar energy every day. The not so good news is that your home may not be very efficient at using the sun’s energy.
Passive solar design is not a new idea and the concepts were being practiced thousands of years ago by other cultures such as the ancient Greeks and even the Anasazi Indians of our southwest desert. Today, passive solar home design is more important than ever as our fuel resources are being depleted and we grow more concerned about our climate.
What is passive solar energy and what does it mean to you?
Solar energy is passive by nature. That means it is delivered to your home without benefit of a truck or power line. (If it requires machinery, such as PV modules or pumps to work it in your home, it would be called active solar power).
You can design or redesign your home to have sunrooms and other air spaces that collect and redistribute solar energy. Solar heating can be incorporated into any style of house, as long as the south side of the house receives full sunlight for most of the day. It can be used in almost any part of the world and can provide a significant portion of the homes heating requirements. In the United States, most areas have enough sunlight to fulfill at least half of a household's annual heat demand.
What are the benefits of creating a passive solar home?
The cost of incorporating solar energy concepts in a new home will increase the cost by only 0-3%, as most buildings codes are already requiring energy efficient windows, walls, ceilings and foundations. Using passive solar energy makes good financial sense and I can’t believe that we haven’t been thinking along these lines all along.
In addition to free heat, passive solar energy provides a wide range of environmental benefits. Passive solar energy can be complemented by using solar panels (active solar systems) and between the two of them a home that has a conventional heating bill of $2400 would be downsized to something like $145 a year. Unbelievable money savings isn’t it?
Basically your goal will be to rely on super insulation, air tight design, energy-efficient lighting, and sunlight to reduce your fossil-fuel consumption. A passive solar home allows low-angled winter sunlight to enter your home through south facing windows. South facing windows are the key words here.
How do you build a passive solar home from scratch?
This first consideration is something that everyone can do. Select a site with unobstructed solar access, which means bright and sunny from 9 a.m. to 3 p.m. Choose your site carefully. Avoid wooded areas on the south side of the house and rule out large obstructions such as evergreen trees, hills or nearby buildings that could block that low angled winter sunlight.
Orient the long axis of your house within 10 degrees east or west of true south. The back, front or the sides of a house can serve as the solar face. South facing glass is the key to passive solar design. When the sun cuts a low arc across the sky during the winter, the glass allows the sunlight into the home to provide heat. Have most of your windows on the south side of the house. Adequate overhangs help to regulate the heat input (you'll get less direct sunlight in the summer when the sun is more directly overhead).
Include an adequate amount of thermal mass in your design. This means solid materials such as tile or concrete. These solid materials absorb solar heat and help stabilize internal temperatures.
A solar design relies on energy efficiency. When a home has been constructed to maximize energy efficiency the building will be easier to heat using solar energy. This means using superior levels of insulation in the ceilings, walls, floors and foundations in order to conserve heat and buffer against outdoor temperature swings. This includes energy efficient windows and providing a way to cover windows at night.
An adequate ventilation system is required to make up for a tight air design around the windows and doors. Installing vapor barriers is advisable on the warm side of the walls to protect the insulation from moisture. Build your house using a rectangular design so that most rooms are heated directly by the incoming sunlight, and have the most frequently used rooms on the south side of the house. Do allow for some sun free rooms so that you aren’t battling sun glare on computer screens and televisions, and so that you have a cooler areas to retreat to in the summer.
Last but not least, install an environmentally responsible back up hating system.
Sources:
The New Ecological Home: A Complete Guide to Green Building Options 
The Complete Idiot's Guide to Solar Power for your Home
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