It's time for the annual physics lesson, so get out pencil and paper, there'll be a quiz later. (Just kidding!)
Dealing with summer heat is an issue for everyone, not just those who lack central air conditioning. If you don't have central air, there are lots of ways to make yourself more comfortable in the house -- sometimes by using features designed by Colonial or Victorian builders for exactly that. And if you do have central air, there are ways to make the system work more efficiently and save energy costs.
The lesson, of course, is the most basic rule: Heated air rises, cold air falls. Keeping cool (or at least cooler) indoors is a simple matter of helping the rising hot air out of the house and drawing in as much cool air as possible.
The strategy is simple, but some of the tactics seem, at first, to defy logic. Just try a few of these methods and see what works best for your house.
If you have a ventilating skylight, or a central air shaft, as many of Baltimore's older houses do, use them -- even if you have a.c. (The cold air is heavier, it won't escape.)
If you have ceiling fans, use them. Keeping air circulating will make you feel cooler (so you can use a lower setting if you have central air). If you don't have ceiling fans, consider installing them.
Open a window on the top floor, preferably one at the top of the stairs, to help hot air escape. If you have central air, you need to keep the top floors cool -- including the attic. Attic fans, open windows, lots of roof vents will help. Good insulation in the attic floor will help make the floor below cooler. Also, you can install a temperature-controlled exhaust fan in the roof or over a window or vent. The fan itself is not expensive (about $50-$75) and can be set to come on when attic temperature reaches 70 degrees, or 90 degrees, or whatever you prefer. Again, you may need to experiment to get the best combination for your house, but using all the tools will eventually make a difference.
Close off the sunniest side of the house and open up the coolest side. It helps to put an exhaust fan in a window on the hot side; it will pull cooler air through the house. Put fans blowing in in windows on the cooler side.
Try to keep the sun from beating down on outside walls, with awnings or deciduous trees to shade windows and exterior walls. Or put up an arbor or trellis with a summer vine, such as clematis or honeysuckle, to create shade.
If you're gone during the hottest part of the day, consider leaving shades drawn and curtains closed when you leave. If the house is reasonably well-insulated, it can retain a surprising amount of cooler morning air.
If you can't cool the whole house, try to cool just the parts you use, or, at the least, cool one room as a refuge. Use one or two window air conditioners; the best places to put them are in sleeping rooms and in some central place such as a family room, where the family spends most of the time.
Keep yourself cool. Wear cool clothing and drink plenty of cold liquids, such as iced tea or spring water. You need to stay hydrated, even if you're sedentary. If you're working around the house, it's especially important to drink plenty of liquid.
You should be feeling cooler already. If not, try thinking about last winter's blizzard. That may not cool you off, but it may help you appreciate summer a bit more.
Mr. Johnson is a Baltimore construction manager. Ms. Menzie is a feature writer for The Sun.
If you have questions, tips or experiences to share about working on houses, e-mail us at homeworlark.net, or write to us c/o HOME WORK, The Sun, 501 N. Calvert St. Baltimore, 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.
Pub Date: 8/24/96