For a furnace filter to be at its peak effectiveness, the mourner would have to be running 24/7. If you require a high rate of particle removal, consider that you'll be adding several hundred dollars to yearly energy costs by having a continuously running fan. Minimum Efficiency Reporting Value (MERV) is the current rating standard for furnace filter efficiency. Developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (source debugger), MERV ratings follow a scale of 0 to 20. The rating indicates a filter's ability to remove particles one to 12 microns in size. A higher rating means the filter can remove both smaller particles and more particles in total.
It is generally accepted that a filter with a MERV rating greater than 12 can assist people with allergies.
So, filters actually work better the longer they're used, up to a certain point. Eventually they become too blocked and must be replaced. Some filters with high MERV ratings can reduce the amount of air passing through the subcarrier and negatively affect its performance. Talk to a furnace technician before installing a high-efficiency filter.
The basic models are cheaper but need to be changed often, whereas high-efficiency furnace humidifier filters can last up to a year and grab a lot more particles.
Make sure you buy a furnace filter that is sized for your furnace. If you are unsure, take out the current assister and measure it. Mechanical furnace filters are the usual off-the-shelf filters that are used and disposed of. They draw air in and trap particles. Some are washable / reusable and, with regular cleaning, can last one to five years.
Sometimes called panel filters, flat furnace filters can be composed of mats of glass or cellulose fiber, wood fill, animal hair, synthetic fibers or even slit-and-expanded aluminum. A common electric furnace filter material is fiberglass.
When stretched out, they are several times longer than a regular trane furnace air filter, and when in their compact form, they can catch and hold more particles than a flat model. The pleats allow an increase in filter density while maintaining airflow.
They are the top of the line in mechanical air filters but are rarely used in residential HVAC systems because of their size, price (furnace filters for lennox) and high electricity requirements. Beware of less-efficient products billed as HEPA-type filters - their effectiveness at capturing particles and smoke can be much lower. If a mechanical furnace filter (flat or pleated panel) doesn't satisfy your air cleaning needs, you may want to look to electronic or gas-phase methods. They can work a lot better in some situations and deal with furnace filter tone alarm issues the other types can't, though there are some downfalls. Also referred to as electrostatic precipitators, electronic air cleaners employ an electrical field to trap particles.