Heating your home through passive solar heating

 According to architect Kelly Lerner, the simplest way to heat your home with the sun is called passive or direct-gain solar heating. Passive is referring to the fact that a well-designed house is just sitting there accepting solar heat through glass, with no moving parts. Sounds simple right? It can be, but it will be more demanding on your home's design if it isn't already equipped for this sort of thing. Both active and passive solar heating systems require work, but active solar heating systems may require additional materials, technology, and energy inputs. This is not to say that active solar heating systems are built in vain...let's just call the passive solar heating system the more "natural" way to do things. The essence of passive-solar design is simplicity and in harmony with natures cycles and rhythms. There are four main features involved:

    * Admitting winter sunlight through south-facing glass
    * Storing the solar heat in thermal mass
    * Keeping the summer sun out of the space via shading
    * Insulating the house to avoid losing the solar heat you collect

Lerner has a few basic guidelines that may help you improve your home's solar gain:

    * Consider your climate zone and work with a sun-chart for your latitude to design windows, thermal storage, shading devices, and insulation.
    * Evaluate your site and make a site plan marking obstructions that can block winter sunlight.
    * Look at your house itself and make notes on your floor plan on where your house has good passive-solar design features, and on areas that could be improved.

 Picture your self in a well-designed passive solar home. In the winter, sunlight comes into the space and warms the floor and walls. Materials that will soak up heat include stone, earth, or concrete. Good insulation will slow heat escaping. A roof overhang in summer will keep out direct sunlight, and flushing the house with cool air at night will cool surfaces for the next day.

 Thermal mass, a class of dense materials that conduct heat slowly, is key factor when considering a passive-solar home. Thermal mass materials, which include stone, brick, concrete, ceramic tile, and water, are useful for natural heating but work very slowly. The art of using thermal mass in passive-solar heating involves:

    * Placing the mass where the sun falls
    * Selecting a thermal-mass material that transfers heat at a desirable rate
    * Providing enough thickness of mass to store heat without overdoing it
    * Insulating the outside of the mass so that the heat isn't lost to the ground or the outdoor air

 So despite the fact that passive-solar heating is more natural, the steps to achieving it efficiently do require some work. But in the end you gain a good picture of your home's assets and liabilities in relation to solar heating, then you can move on to the bigger stuff like adding or changing windows if you need to.