(MONEY Magazine) – Hey, it really is tool time! Americans will spend a projected $117 billion on home improvement this year, a whopping 20% more than in 1991. While kitchen and bath overhauls remain perennial favorites, other jobs may actually provide bigger payoffs for your well-being as well as your pocketbook. A dozen remodeling experts we consulted pointed to the following three increasingly popular projects, which reflect concerns about the weather, the planet and the elderly. Bring the outdoors in. Adding extra-large windows or even a sunroom is a surefire way to enjoy the great outdoors in temperature-controlled , mosquito- free comfort. According to a 1993 Remodeling magazine survey, homeowners recouped at resale a reassuring 71% of the $22,000 average cost of a sunroom addition. It's true that these jobs aren't cheap. Simply replacing a traditional three-foot-by-five-foot single-paned window with a larger five-foot-by-eight- fo ot double-paned one will cost about $3,000. But the flood of light will console you, as will the knowledge that double-paned windows are four times more energy-efficient than the single-paned variety. If you go for the typical addition, your $22,000 can yield a 12-foot-by-16-foot custom-built space with insulated glass windows, ceiling fan and terra cotta tile floor. Choose ventilating skylights such as those made by Velux in Greenwood, S.C. (cost: $235 and up for a 21 1/2-by-44-incher), which keep you cooler by allowing rising heat to escape. When you're done, roomscape. "If you put the same flowers and plants that grow in your backyard in your sunroom, the passage between the two is seamless," says Santa Ana, Calif. interior designer Carole Eichen. She ought to know; she added $750 worth of dracaena, grape ivy and other greenery to the space pictured at right, above. Catch the green wave. With the increasing number of environmentally-friendly renovation materials available now, it's easy to spare the planet and your bank account too while you build. "When you look at the costs of maintenance, replacement and energy use," says Kirsten Childs, a New York City designer who specializes in green upgrades, "you realize it's usually cheaper to remodel environmentally." Consider recycled products. Sur-Flex, a sturdy nonslip material made of recycled rubber by Top Trowel in Manhattan Beach, Calif. (cost: $3.50 a square foot), is ideal for resurfacing your garden path or patio. Easy to clean, it's more crack-resistant than concrete and costs 25% less. You can also cut energy use. For example, install a heat- or movement- detecting occupancy sensor to automatically switch lights on or off when you enter or leave a room; the cost for a standard 300-watt unit from Tork Electronics: $35. Installing such sensors in every room can shave your electric bills by 10% to 20%. Become elder-friendly. The U.S. Census Bureau projects that the number of U.S. citizens age 75 and over will increase 28% by the year 2010, to 19 million. As a consequence, more of us face the prospect of housing an elderly relative. A popular solution: creating a so-called grandparent suite. The most elaborate include a bedroom, private bath, kitchenette and even a separate entranceway, with all doorways at least 34 inches wide (two inches wider than standard) to accommodate wheelchairs or walkers. If you're not eager to shell out the $21,300 that Remodeling estimates it costs to convert an attic space to a bedroom and bath, consider more modest alterations. These include installing grab bars in the family shower ($30 for a 24-incher from Taymor in Hayward, Calif.) and replacing doorknobs with easy-to-open lever handles ($12 for the Leveron brand from Lindustries in Auburndale, Mass.). Like sunrooms, these changes make your home more attractive to buyers. And even if your folks never need to move in, you'll be prepared to stay put well into your own golden years.