Furnace filters are an essential part of any home's heating and cooling system. They help to keep the air in your home clean and healthy by trapping pollutants, allergens, and other airborne particles. With so many different types of furnace filters available, it can be hard to know which one to choose. In this blog post, we'll break down the different types of furnace filters, their filtration levels, and rating systems for these levels.
Types of Furnace Filters
Fiberglass Filters
These are the most basic type of furnace filter, made of layered fiberglass fibers. They are inexpensive but offer limited filtration and need to be replaced frequently.
Pleated Filters
Pleated filters are made of paper or polyester material and offer better filtration than fiberglass filters. They are also more durable and can last up to six months before needing to be replaced.
HEPA Filters
HEPA stands for High-Efficiency Particulate Air, and these filters are the most effective at trapping airborne particles. They are made of a dense mesh of fibers and can remove up to 99.97% of particles that are 0.3 microns or larger. However, they are also the most expensive type of furnace filter.
Specialty Filters
Most filters fall into the categories listed above. A couple less common types are:
Electrostatic Filters: These filters use an electrostatic charge to trap particles. They are not commonly used anymore.
Charcoal filters: These are intended to reduce odors by absorbing them using activated charcoal. They do not offer any additional filtration benefits when if comes to removing particulates.
Filtration Levels
Furnace filters are rated based on their Minimum Efficiency Reporting Value (MERV), which measures their ability to capture airborne particles. The higher the MERV rating, the more effective the filter is at removing particles. Here are the most common MERV ratings:
MERV 1-3
These filters are the least effective, capturing only larger particles like dust and lint.
MERV 4-7
These filters are better at capturing smaller particles like pollen and mold spores.
MERV 8-11
These filters are even more effective at capturing particles like smog particles and smoke.
MERV 12-16
These filters are the most effective, capturing even the smallest particles like bacteria and viruses.
MERV 17 and Higher
This is the highest level of filtration available, these are also used in biomedical settings such as hospitals, and are capable of filtering out micro-pollutants.
Other Rating Systems
In addition to MERV ratings, some filters are also rated using other systems, such as the Filter Performance Rating (FPR) or the Microparticle Performance Rating (MPR). These systems measure different aspects of filter performance, such as airflow and particle capture efficiency.
How Often Should I Replace my Filter?
The frequency at which you should replace your filter depends on several factors, including the type of filter you are using, the size of your home, the number of occupants, and the presence of pets or allergies.
As a general rule, most filters should be replaced every 1-3 months. However, some high-efficiency filters may last up to 6 months. It is always a good idea to check the manufacturer's recommendations for your specific filter.
Why Should I Replace My Filter?
There are several reasons why it is important to replace your furnace filter regularly:
Improves indoor air quality: A dirty filter can't effectively remove dust, pollen, and other allergens from the air, leading to poor indoor air quality and potential health issues.
Increases energy efficiency: A dirty filter can cause your HVAC system to work harder to maintain the desired temperature, leading to higher energy bills and potentially shortening the lifespan of your system.
Reduces the need for repairs: A clogged filter can cause your furnace to overheat, potentially leading to costly repairs.
Key Points
Your furnace filter can make a big difference in the quality of the air you breathe.
There are many types of filters available depending on the desired level of performance: you get what you pay for.
The higher the MERV number, the better the filtration.
Most filters need to be changed every 1-3 months.