Energy adviser: Replace furnace filters for efficiency and comfort



Many home maintenance tasks fall into the boring-but-important category. Replacing furnace air filters is one of them. Smart homeowners take time to inspect and replace their heating-cooling air filters when the weather is mild, before winter’s cold temperatures put more demand on their equipment.

Keeping up with air filters means more indoor comfort and more efficient systems. Dirty or plugged filters can cause the entire heating system to run at a higher temperature for much longer and can use more energy, according to heating and cooling equipment experts.

There are many types of furnace and air conditioner filters available for the home, from fiberglass to pleated and electrostatic. The website offers an easy-to-read comparison of seven types of filters and air cleaners to help determine cover what type might be best for you.

Factors to consider when comparing filters:

• There is no difference between a furnace filter and an air conditioner filter.

• The brand name is not important. Choose the characteristics you like and then compare filters of that type to make your final choice. For example “don’t spend time reviewing electrostatic air filters if you can’t do regular maintenance,” write the experts at

• You may be best served by a combination of filters and air cleaners to obtain the indoor air quality you are looking for. Air filters and air cleaners are not the same. An electronic air cleaner charges dust particles as they pass through and attracts them to a collection plate. Other cleaners may eliminate mold spores or bacteria. They can be used in combination with a regular air filter.

• When replacing filters, it is never a good idea to stack more than one air filter in your heating-cooling equipment. Stacking can restrict airflow and put strain on your entire blower system. How frequently you change or clean filters will vary, depending on your home, lifestyle, whether you have pets and other factors. Early fall is a great time to make an inspection.

‘Green’ filter alternative

If you are looking for a “green” alternative to tossing used filters into the trash, consider an electrostatic air filter. The devices are washable. They last for years, with many offering lifetime warranties. They don’t use electricity and don’t produce ozone. A one-time cost saves you money over time.

But maintenance is important with these filters. Regular cleaning is required to avoid airflow problems. Interested buyers should know that there are many designs and brands, some with low quality. So be informed and make buying comparisons.

Least-favored by experts are the inexpensive fiberglass filters found in most home improvement departments and hardware stores. They are not efficient, allow most dust to pass through them and are disposable, going into landfills.

On the other hand, pleated filters are the most favored because their design increases the filtering surface area and dust-loading capacity. They last longer and come in a variety of materials — cotton, synthetic blends and polyester — some with electrostatic characteristics.

Energy Adviser is written by Clark Public Utilities. Send questions to