When reviewing a prospective site, one should be able to stand where the house will be located, face due south, look up at a 30 degree angle, and see clear sky to the south and for about 45 degrees to the east and to the west. For those who understand solar geometry, use the SunAngle . The longer and thinner the house is, the better. The longest side of the house should face south, with as much area as possible facing the sun. Return Orientation A house can be oriented as much as 20 degrees off from due south while still giving adequate performance, but it is best to orient the long side of the house facing due south.
Maps are available showing the correction from magnetic south to true south.
Once the shape and location of the house provide access to the sun, the house must invite the sun in. Windows must be maximized on the south side and minimized on the other sides, especially the north side. The south facing windows should not be made with low e glass that has a solar heat gain penalty, as this will block much of the sunlight. Windows on the other side of the house should be made with low e glass. Return Energy Absorbtion Having invited the sunlight in, it is necessary to absorb it.