North Lawrence residents Tom Mersmann and Robin Gingerich have taken a few steps to make their home more energy-efficient, which they say has cut their bills by 25 percent.

Mersmann and Gingerich also installed five rain barrels around the house to cut back on water usage.

The addition of awnings on the south and west sides of the house have helped keep Mersmann and Gingerich’s upstairs room cooler than before.

The green and lush days of summer are here.

And Robin Gingerich and husband Tom Mersmann are enjoying the heat from the confines of their North Lawrence home — a place that has yet to use its air conditioner in 2010 despite quite a few sweltering days.

“I’m not a person who likes to be uncomfortable,” Gingerich says. “So, when we first started talking about trying to save energy, which is important to us for a lot of reasons — environmental and financial — I was like, ‘Well, I can’t give up air conditioning.'”

They didn’t kill the air conditioner, but rather they decided to take small measures to make sure it wasn’t such a taxing proposition to stay cool. Little changes like putting up awnings and using an exhaust fan have helped the couple cut their energy usage 25 percent since they first began making improvements a few years ago. Doug and Shirley Hitt of Lecompton have made similar easy changes and cut their energy consumption by a third over the past four years.

“We did intentionally record our kilowatt hour usage over four years and then did some things — just the most simple of things — to see what effect they had,” says Doug Hitt, who says he added CFLs, turned down his water heater, put down the shades and installed a programmable thermostat. “I feel like we didn’t do anything that cost us a lot of money. … But maybe what people could take away from that is that little things really mean a lot.”

So, why not take advantage of a warm weekend or two to change some of those aforementioned little things? What you do to your abode this summer might make it so green that it pays off for dozens of summers to come.

Here are some of the easiest green summer projects as suggested by Eileen Horn, the city and county’s sustainability coordinator; Linda Cottin, owner of Cottin’s Hardware, 1832 Mass.; Rich Wenzel of the Lawrence Sustainability Network’s Energy Interest Group; and Asa Collier, owner, Blue Sky Wind, Solar and Home, 920 Mass.

• Fill in the gaps. Check your windows, doors and exterior walls for cracks and fill them with caulk. You can also add weather stripping or add storm windows and doors.

• Redecorate. Spend a day repainting a room with low- or no-volatile organic compound (VOC) paint, which create a better indoor air quality. Add a dimmer switch, swap out your old bulbs for CFLs and add thermal-lined drapes to eliminate drafts.

• Plant a tree. Planting trees near your home can keep it cooler in the summer and still allow the sun to help heat your home in the winter. Cottin says this is a great way to keep your house cool and help the environment, while adding to your home’s curb appeal.

• Add a clothes line. An efficient and cheap way to get clean clothes is to invest in a clothes line. They cost less than $100, says Cottin.

• Got fans? Use them! Using fans when you are home, rather than letting the air conditioner kick on, is a big energy saver. Just having air moving through a room can cool off a person significantly, say homeowners Mersmann, Gingerich and Hitt.

• Drain and filter. Drain your hot water heater once a month to keep build up from making it inefficient, says Wenzel. Also, change your furnace filter every three months to improve its efficiency.

• Insulate, insulate, insulate. Spend time insulating your copper water pipes, your hot water heater and even your garage door. Similarly, check your level of insulation in your attic and find out if you have insulation in your walls. Also, Horn notes that Aug. 1 is the day weatherization grants become open to area residents — if you qualify, you could get help paying for insulation, as well as storm doors and windows.

• Attic airflow counts. It’s not just how insulated your attic is, it’s how cool it is as well, especially this time of year. Collier says adding solar-powered attic venting can lower the temperature in your attic 50 to 60 degrees — making things much easier on your air conditioner.

• Find time for timers. Add a timer to your hot water heater and look into installing a programmable thermostat that you can set to keep you from wasting energy when you’re not at home or happen to be sleeping.

• Capture the rain. Hooking up a 50-gallon rain barrel can cost about $100, but the savings in water can be huge — and handy. Mersmann says adding rain barrels has helped him both save water and keep his vegetable garden going during dry spells.

• Got more time? Do the research on things you can’t do yourself. Spend an afternoon checking on blown-in insulation, energy-efficient appliances and green solutions like tankless or solar water heaters. Also, check into the tax advantages of new windows, doors and insulation. You can go to www.energystar.gov for more information. Also, for more ideas on what you can do to green your home, contact Wenzel and the Lawrence Sustainability Network’s Energy Interest Group at 917-9344 or e-mail altairfour@hotmail.com.