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If you live in a place where weather gets extreme, this can mean substantially higher energy costs. Here are four low-cost, high-impact changes you can make this summer on your own to save money and keep your home more comfortable this all year round.

 

Clean your window sills
A few seasons worth of dirt and soot can prevent your windows from closing all the way. Even a little air getting in can make your AC less efficient and raise your electric bill. Drafty windows are the top energy leak in a typical home, accounting for up to 25% of a home’s energy loss.
Cost: $0-5 (cleaning spray and paper towels)
DIY level: Easy. You can even make this a chore for the kids!

Install a door sweep
“A common place where air leaks occur is under the door leading from the house to the garage because they are often not as well sealed as doors leading directly to the outside,” says Energy Star. Install a door sweep to seal the gap between the bottom of your door and the threshold to prevent cold air from escaping your home.
Cost: $10-15 (per door)
DIY level: Easy. Use a drill to make holes in the door and screws to attach the sweep.

Caulk your windows
Window air leakage can be reduced by applying a continuous bead of caulk around the window trim where it meets the wall, at the mitered joints of the trim, and between the trim and the frame. Make sure the caulk is intended for indoor use and can be painted. Using Charlotte, NC as an example, the Department of Energy estimated that the average homeowner could save 14% on heating and cooling costs each year with proper air sealing and insulation.
Cost: $3-5 (caulk)
DIY level: Medium. Caulk can get messy, so go slow.

 Use this handy checklist to assess your HVAC system 

Check your ducts
Ducts are used to distribute AC and heat throughout houses with forced-air systems “In typical houses, about 20% of the air that moves through the duct system is lost due to leaks, holes and poorly connected ducts.” says Energy Star. “The result is an inefficient HVAC system, high utility bills, and difficulty keeping the house comfortable, no matter how the thermostat is set.” You can check all the ducts you can access, such as those in the attic, crawlspace, or garage. Look for holes and tears, and seal them using mastic or metal tape.
Cost: $5-10 (roll of tape)
DIY level: Medium. It’s just taping, but you’ll likely be dealing with tight spaces and a few creepy-crawlies.

Change your filters
Dirty and poorly sized filters restrict airflow and make your equipment work harder. Using a properly fitting filter and changing it often will make your furnace and A/C more efficient. 
Cost: $1-20 (filter)
DIY level: Easy. It’s just locating the filter and buying the right replacement size.

Clean your A/C Unit 
Dirty and poorly maintained units can do their job properly. It’s important to keep your unit clean. Remove leaves and debris from the outside of the unit then clean the unit. Before cleaning, turn the thermostat off then turn the main power switch off to the A/C unit. Remove the top of the unit, carefully. The fan motor may be attached to the top. Place the top where the fan blades and wiring won’t be damaged. Vacuum dirt and debris out of the bottom of the unit. Using the brush attachment, very gently vacuum the fins. Use an up-and-down motion; vacuuming across the fins can bend them. Spray the outside of the fins with a coil cleaner or detergent/water mixture and wait 5 minutes. (Avoid spraying the fan motor.) Use a cooling fin comb to straighten any bent fins. Re-assemble and turn the main power switch on and set the thermostat to cool. Go outside and listen for any odd noises; if you hear anything, call a professional as soon as possible. Clean your unit that the end of cooling season and then cover it until the next cooling season.  
Cost: $1-20 (vacuum attachment/cleaning solution)
DIY level: Medium. It takes time and supplies

Replace damaged A/C Insulation
Rotting insulation on your outdoor A/C lines can cost you energy. The fix is simple. The Family Handyman will show you how to fix the insulation and tell you where to get the special insulating foam.
Cost: $10-30 (new foam and insulating tape)
DIY level: Medium. Measuring, cleaning, ordering supplies.

 

Tada!