The high-tech house offers relief irom summer heat not only by
means of power-hungry air conditioners, but also through shade
trees placed along the south side of the building.Even
in the active solar house, these straightforward measures help
heal the house without pumps, motors, ducts, and burners.For a house in the
Northeast, for example, it makes good solar sense to design small
windows on the north facade, to shut out cold winds, and large
windows on the sunny south side, to absorb the warm rays.In the summer this arrangement prevents gaping losses of cooled air; in
w inter it locks out inrushes of cold air.Active solar systems
rely on moving parts such as heat exchangers and computercontrolled window curtains.Increasingly, so-called solar mass is being used to enhance the
natural space heating that occurs when the sun streams in
through windows.Other simple design measures also qualify as passive improvements in heating and cooling.Similarly, a walkway between an unattached garage and a
house can cut heating losses through an uninsulated garage.Unconventional ways of improving heating have received
widespread attention since the 1973 oil embargo.So-called
passive solar systems stress proper orientation of the house and
using the sun to heat spaces and materials.Someone arriving opens the outer door, enters the foyer, and
closes the door.The methods
hinge largely on harnessing the power of the sun.Building a sun room on the south side will
bring warmed air into the rest of the house, but a low stone wall
at the rear of the sun room, rather than a standard wall, will absorb the sun's heat and reradiate it into the house long after the
sun has set.Heat in winter
can come from a gas-fired furnace and also from warm air radiated from a solar mass beneath the floor.A simple front door can be enhanced with a small foyer that has an inner and outer door."Passive solar" really means smart design.Smarter design and new
technolog>' are keeping the options open.He may hang his coat and leave his muddy shoes
there, then open the inner door and enter the house.