As the warmer weather joins us once again, many folks will soon be plugging in room air conditioners or turning on their central cooling systems.

Inspecting, servicing or replacing air conditioners now will go a long way toward helping to make this a cool, comfortable and energy-efficient summer. Here’s some advice that will help.

Many central air conditioning systems operate at only 55 to 70 percent of their rated capacity. This is due in part to over-sized equipment, clogged filters or leaky air ducts. Regular inspections and maintenance is an important step in keeping central air conditioners running at peak efficiency.

If you’re in the market for a new central air conditioner, purchasing a model that’s earned the ENERGY STAR can save up to 20 percent on cooling costs.

NSTAR is offering rebates from $300 to $600 on qualifying high-efficiency central air conditioning systems, with certain systems also qualifying for a $1,500 federal tax credit. For more information, call 800-473-1105 or visit www.mycoolsmart.com.

To help ensure peak operating efficiency of your window air conditioners, be sure to clean the filters periodically throughout the summer. Avoid using air conditioners to cool spaces larger than they’re designed to handle and, where possible, install them in windows that are not south-facing to keep the sun from beating down on them all day.

As with central systems, when shopping for a new window air conditioner, look for a model that’s earned the ENERGY STAR. They use at least 10 percent less energy than conventional models and often include timers for better control. NSTAR is offering rebates of up to $30 on qualifying ENERGY STAR-rated room air conditioners.

For more information or to read about other energy-saving tips, rebates and programs, click on “Energy Efficiency” in the left-side menu above.

In my next column, I’ll discuss outdoor grilling and other summertime tips to save energy.