How to Maintain Central Heating and Cooling Systems

Tips for do-it-yourself and professional maintenance for your central heating and cooling systems

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When in peak condition, Central heating and cooling systems give a great mix of efficiency and comfort. If left without proper maintenance, however, that efficiency plummets and takes your bank account with it.

Most maintenance for central heating and cooling systems should be left to the professionals, but some general upkeep can be performed by homeowners of any skill level. Here’s a list of suggested maintenance for central heating and cooling systems, including how-to guides for basic maintenance, to ensure you keep the cost of comfort at its lowest.


Air Filters

Air filters on central heating and cooling systems block dust, pollen, and other small particles from entering your home. Eventually, air filters become clogged by these particles, causing a reduction in energy efficiency from 5 to 15 percent, according to the U.S. Department of Energy.

If you consider it can cost initially cost an extra thousand dollars or more to buy a central air conditioner that operates at 15 percent higher efficiency than another model, ignoring air filter maintenance is like throwing away the money you spent on a better unit. The U.S. Department of Energy recommends that filters be replaced every one to two months during seasons when the air conditioner is frequently in use. And it only takes about 15 minutes.

Some central air conditioner filters are reusable while others are disposable. Before you replace your air filter, check to see which kind you have. If you have disposable filters, numerous online retailers as well as local big box hardware stores should the replacement filters you need.

Step 1: Find your filter

Central air conditioning filters will be along the return duct, including inside the air conditioner or connected to the duct itself. No tools are needed: the air filter slides in and out of the return duct. It’s usually rectangular and about one inch thick. Other dimensions vary, but expect the filter to be a little less than two feet long by one-and-a-half feet wide. Ask your installation contractor about the air filter’s location if you’re not able to find it.

Step 2: Remove and clean filter

No tools are necessary. The filter will slide right out. If it’s reusable, clean the filter according to the manufacturer’s specifications.

Step 3: Insert new filter

Slide the clean or new filter into the return duct through the slot where you removed the old one. Be sure that the filter is set in the correct direction--look for written guides and icons on the slot or filter. Welcome to a more efficient central air conditioner.

Clogged drains:

Central air conditioners feature drains used to remove condensation and humidity. These can become clogged over time. Unclogging the drains is simple: push a wire through the drain channels to knock out the gunk.

Expert Level Central Cooling Maintenance

Other maintenance should only be undertaken by professionals or homeowners with advanced knowledge. This includes:

Cleaning coils:

The evaporator and condenser coils collect dirt overtime, which limits air flow and the amount of heat removed by the air conditioner. These should be cleaned, at the most, every year.

Coil fins:

Fins on the evaporator and condenser bend over time, which blocks air flow. When this occurs, the fins should be straightened.

Blower adjustment:

The blower may wear down over time and need an adjustment to boost air flow.

Adjust refrigerant:

If your air conditioner has too much or too little refrigerant, an essential chemical component that creates cool air, your system will operate inefficiently.


Air Filters:

A similar air filter to the ones seen on air conditioners are featured on nearly all central heating and cooling systems. Your furnace relies on a filter to block out dust, mold, and other particles, which collects dirt over time, leading to falling energy efficiency.

The filter should be changed regularly--as much as once a month during seasons when it’s in constant use. A filter change takes just a few minutes. The steps for replacement are similar to central air.

Step 1:Find your filter

The filter should be at the front of the furnace. Often, it will be set in a slide near the bottom of the furnace. Like air conditioning filters, it will likely be rectangular, about an inch thick, and about two feet long by one-and-half feet wide.

Step 2: Remove and clean old filter

The old filter should slide out easily. If it’s reusable, clean it according to the manufacturer’s directions.

Step 3: Insert new filter

Slide the new filter in the same slot from which you removed the old one. Make sure it’s facing the right direction.

Pilot Light:

If you have natural gas, check whether the pilot light is on and that it’s blue. If you’re trying to heat your home but getting nothing except cold air blowing in, a pilot light that’s gone out is the likely culprit. If the pilot light is yellow or orange, there may be a mechanical issue with the system. Seek professional maintenance if the light is any color other than blue.

Expert Level Central Heating Maintenance

Other maintenance should only be performed by professionals or homeowners with advanced knowledge. These tasks include:

Belt adjustment and lubrication:

Belts inside your central heating dry out and become worn over time, reducing efficiency. These should be adjusted and lubricated, at the most, annually.

Interior cleaning:

Dirt will inevitably end up in your central heating, requiring a professional cleaning. Nearly all elements of the furnace must be wiped down and cleaned out. A dirty furnace can significantly reduce efficiency. Get a contractor to clean your furnace every few years.

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About the Author

Rachel Wright is an SEO content editor at Reply! with more than 10 years of editing experience. She enjoys interior design and gardening. To share home improvement ideas, find her on Google+.