Tips for cooling your house in summer
Feeling the heat? Experts offer options beyond AC for keeping your cool at home
Illustration by David Cowles. (David Cowles, Special to The Baltimore Sun / July 17, 2012)
Hundreds of thousands of homes in the Baltimore-Washington region lost power from the ferocious storm in late June. That was a bummer. But when temps soared past 100 degrees in the week that followed, what started as a bummer became much more serious. Indoor temperatures were stifling, making sleep nearly impossible and daily activities unbearable. Dozens of deaths nationwide were linked to the heat wave, including at least 20 in Maryland.
But with some climate experts foreseeing a future of ever-hotter summers, with wilder, more frequent power-snuffing storms, homeowners who yearn to be cool as cucumbers may want to consider energy-conserving options that go beyond the everyday comfort of air conditioners.
It helps to remember that air conditioning has not been around forever. It was invented in the early 1900s and wasn't common in residences until the 1950s. Many people in the hottest parts of the world still don't rely on it. Instead, they keep cool through the use of cross-ventilation, shade, fans, light-colored roofs, greenery instead of asphalt, and windows that are shielded from sun yet allow heat to escape.
Kathleen Lechleiter, principal of k.lechleiter Architect in Baltimore, said the city's rowhouses were originally built with large windows for cross-ventilation, but those were replaced with smaller windows once air conditioning came along. Now, she's restoring those large windows, and also adding ceiling fans.
"Everything old is new again," said Lechleiter, who is also planning to install a green roof on one of her Baltimore projects. The roof has vegetation that absorbs heat in summer and insulates the property in winter. "It will help the homeowners keep the energy bills down," she said.
Building experts agree a light-colored roof or one with vegetation is a tremendously powerful weapon against a sweltering indoors.
"A light-colored roof would reduce the heat gain in the house," said Lisa Ferretto, architect and sustainability coordinator with Hord Coplan Macht, an architecture and design firm in Baltimore. "If everyone in Baltimore did it, we would reduce the urban heat island effect."
But that's not likely, at least not in the short term, because replacing a perfectly good roof is too expensive to be practical. However, local architects and landscapers have plenty of other ideas for keeping homes cool and comfortable with minimal energy use.
Properties with grass and trees are cooler than ones surrounded by asphalt, said Michael Martin, founder and president of Live Green Landscapes, a Reisterstown-based firm. When considering temperature control, Martin positions trees to shade the afternoon sun, which is hotter than the morning sun, he said.
Another idea, more suitable for suburbs than city life, is to install an outdoor kitchen so the house doesn't heat up from cooking.
"Your air conditioning is working less when you're cooking outside," Martin said. However, removing grass and trees to create such a space will ratchet up temps in the backyard. Martin recommends using light-colored pavers, which radiate less heat than darker-colored ones.
"From a heat standpoint, if you're using a darker paver or you're using a darker natural stone, the sun's going to absorb into that a little bit more," he said. "If you're using tans and lighter colors, the sun will not absorb into that and not get so hot in a patio situation."
Trees provide valuable shade, particularly when they are positioned to shield a house's southern exposure. Ferretto recommends deciduous trees, which provide shade in the summer, then shed their leaves in time to provide warming sun in winter.
Ferretto had a white roof installed on her own Baltimore rowhouse, and collected about half the cost of insulating her attic and sealing off air leaks through grants from the Maryland Energy Administration and the BGE SmartEnergy Savers Program. "I had no insulation in my attic at all," she said. The sealing saved energy by keeping air from escaping, particularly in places where walls come together, she said.
She also recommends placing air-conditioning units on the north side of a building. "If it sits in the sun all day, it's going to be working harder," she said.
Eric Beck, a principal with architecture firm Beck, Powell & Parsons in Towson, said much can be done with new construction to maximize energy-efficient interior comfort. Measures include proper attic ventilation, light-colored roof shingles, overhangs on south-facing windows, double-pane or triple-pane windows that block heat and cold, and weatherstripping to keep cool air — or warm air in winter — from escaping.
Whole-house fans are particularly beneficial those times of year when the nights are cool and days are warm. During the cool nights, open the windows to let in the cool air and run the fans to disperse it, he said.
He also recommends swapping traditional light bulbs for the new compact fluorescent bulbs, which give off far less heat.
Inside the house, tile and concrete floors absorb and release heat more slowly than carpet or wood. That's great if the floors are someplace that doesn't get much heat and sun. But if the tile or concrete is in a room with southern exposure, it will stay warm for a longer period of time. Also, it will be cold in winter.
David Lopez, an architect with Hord Coplan Macht and adjunct professor at the Maryland Institute College of Art, recommends creating finished basements to take advantage of the cooler air underground. Use ceiling fans (when there's power) to keep the air circulating, and install a skylight at the top of stairs, which can be opened to let hot air escape, he said.
Lopez, who teaches design/build in the environmental design department, got some ideas about how to deflect heat while working on a recent project with MICA undergraduate students. They traveled to Haiti and created a prototype of transitional housing for people to live in after disasters, particularly in tropical climates. One goal was to keep the interior temperature as reasonable as possible, and his team achieved that by creating a double wall that trapped heat and allowed it to ventilate from the top.
While most people aren't going to add a second wall inside their existing one, they can allow heat to escape through windows and vents on top floors. Another idea from Lopez: If a house has south-facing windows that absorb heat, shade them with awnings or an architectural structure. Window planters are attractive and absorb the sun's heat, he said.
Lopez said the goal is to keep the windows open. Light-colored blinds provide some benefit, but only after the heat has entered the house.
"I think the important thing in rowhomes is to keep the air moving as much as possible," he said.
Fans can do tremendous good when there's power, but if there's an outage, it's time to rely on cross-ventilation and "stoop culture," Lopez said.
Other low-cost technologies that he said could be considered include "swamp coolers," which use water evaporation to cool air. They're not common here because they would only be used in the hottest months. But that may change.
"Obviously, the climatology of our region seems to be shifting," Lopez said. "So these types of things might come into consideration more for Baltimore residents."
5 tips to keep home cool
1. Use energy-efficient windows and weather stripping to keep cool air in and warm air out. Install large windows for cross-ventilation.
2. Excavate or finish a basement, then install a whole-house fan to keep the cooler air circulating.
3. Add a window or skylight on the top floor, to let warm air vent.
4. Invest in a light-colored roof, or a green roof with vegetation.
5. Build an outdoor kitchen, using light-colored materials for the patio surface.