When it comes to home improvement, furnace filters are among the least exciting products. You have none of the danger and effectiveness of power tools, none of the visual impact of perfectly mitered trim, and certainly none of the security that comes with big investments like new windows or a new roof.
But even small things can make a big impact, and the right furnace filter can save you money and improve air quality. Filters were originally intended to protect the moving parts of the oven. But thanks to advances in technology, filters now prevent harmful particles from getting back into the air you breathe at home.
Heater filters are rated by their Minimum Efficiency Value (MERV). The higher the value, the more efficiently the filter retains air particles. The number ranges from 1 (least efficient) to 20 (most efficient). Read more about MERV values below.
Disposable fiberglass filter
A disposable fiberglass filter is an option that comes to mind when you think of an “oven filter”. It is made from 1 inch thick spun fiberglass fabric and only prevents larger particles such as dust, lint, and debris from clogging your system. They have a MERV rating of 2 to 3 and only cost $1 to $2. Although they are very inexpensive and work well for renters and people without allergies or asthma, they have little or no effect on cleaning the air.
Pleated filter for single-use
Disposable pleated air filters, a popular option made from polyester or cotton paper, can remove some small particles like spores and mites, improving air quality.
These options have a MERV reproof of 6 and cost $4 to $5. While relatively inexpensive, they are also made from eco-friendly materials and retain some small particles. However, they can offer more resistance to airflow, making your rig more expensive to operate.
Highly efficient pleated filter
Highly efficient pleated filters are the forefathers of oven filters. They are made from a 4 to 5 inch thick pleated synthetic cotton fabric attached to a very sturdy metal mesh to prevent leaks or flapping. These filters are a little pricey at $100, but they have an excellent MERV rating of 14-16, making them suitable for hospital use.
Using them at home can be difficult as they are usually used in special cases due to their thickness. But they can filter out the smallest particles and are beneficial for people with respiratory problems or autoimmune diseases.
Disposable electrostatic filters
A disposable electrostatic filter contains self-charging electrostatic cotton or paper fibers that attract and retain small particles. With a MERV of 10, these standard-size options are affordable and a good solution for homes with children, pets, or smokers. If necessary, special sizes are expensive, which leads to higher costs if they are regularly replaced over several years.
Similar to their disposable counterparts, reusable electrostatic filters contain self-charging cotton fibers that attract particles. Permanent options have a removable, machine-washable oven filter that you can reuse for six to eight years. With a MERV rating of 8, they produce little waste, are more effective than pleated air filters, and are a good option if you’re using a standard size. However, they are less effective than electrostatic models and custom sizes are expensive.
Denser than fiberglass, this reusable filter traps more particles in the air. It is available in either a flat or a folded version, up to four inches thick. It captures up to 91% of common airborne particles, including pollen and dust particles, and has a MERV rating of 8. The downside is that these options don’t eliminate the need to replace the HVAC filters or coils, at least all to clean for a few years, as some particles still slip through.
A High-Efficiency Particle Air (HEPA) filter blocks up to 99.7 percent of airborne particles that are 0.3 microns or larger, but it doesn’t come in sizes that fit standard ovens.
Because HEPA filters are so dense, they can reduce airflow into the oven. Therefore, like high-efficiency pleated filters, they are normally only used in commercial furnaces or in hospitals. Although these filters block most airborne particles and provide better air quality with a MERV rating of 16-20, they are not suitable for most home stoves.