If you are designing a new home and are undecided about whether or not you need to have mechanical air conditioning, it would be well worth your time and money to talk to an architect who understands green design principles about natural air conditioning for your home. Designing your home properly can reduce or eliminate your need for an air conditioning system.
Your architect will need to consider the environment and your site location. Siting the house properly to take advantage of sun angles and natural winds will go a long way in naturally air conditioning your home. This is an important part of green home design.
Achieving natural air conditioning depends, in part, on obtaining cross ventilation in all living spaces. You will need to be sure to orient operable windows as far apart as possible to take advantage of cross ventilation.
Clerestory windows, or high wall windows, are a real help when trying to naturally cool your home. When the clerestory windows are made operable, you create what is called a "chimney effect." With low and high windows both open, cool air can enter your home through low windows and hot air can escape through your clerestory windows.
If possible, your architect should place most of the glass on the north and south walls, while limiting glass on the east and west walls. This will minimize solar heat gain from the east and west when the sun is at low angles in the morning and evening hours.
Talk to your architect about designing large overhangs. Overhangs will shade your walls and glass from the sun, which will reduce solar heat gain and assist with natural air conditioning.
Super insulate walls and ceilings. The best insulation that you can invest in is the spray-on foam. There are even soy based foam insulations now that are environmentally friendly and seal all cracks.
Ventilate your attic space and any cathedral ceilings with plenty of soffit vents, ridge vents, and gable vents. This will keep your attic area a lot cooler.
Keep your roofing material light colored and/or reflective. This reflects the sun's radiation away from your home. The amount of reflectivity is referred to as albedo. You should shoot for a rating of 29. Most routine materials will disclose this rating as part of their performance information.
Keep paving materials, such as driveways, walks, and porches light colored. Use no asphalt paving. Instead, choose light colored concrete. Cool breezes will become hot air as they travel over dark materials and will bring more heat to your home.
Plant landscape borders around the walls of your home. Landscape soaks up heat.
Install ceiling fans in all living spaces of your home. Energy star rated fans are available and are the best to choose.
Reduce the use of incandescent light sources in your house to as close to zero as possible. Utilize cooler, more efficient light sources, such as CFL's or LED's. Look in the resource section for more information on purchasing CFLs' and LED's. They cost slightly more up front, but reduce your energy consumption, last longer, and don't throw off heat like incandescent light sources do.
Install Low E 4 windows glass in all windows.
Orient your home at a 45 degree angle to the prevailing wind to optimize cross ventilation in the home.