Generally, this is how long a filter lasts based on MERV ratings: MERV 1-4 furnace filters should be replaced once a month. MERV 5-8 filters need to be changed roughly every 3 months. MERV 9-11 filters require replacement every 6 months.
The middle-efficiency range of MERV 5-10 likely requires filter changes somewhere around two or three months. However, this mid-range really varies depending on other factors and filter material. Air filters with a MERV 11 rating or higher rating can usually go between three and six months before replacing.
In most cases, a MERV 11 air filter isn't too high for residential use. Generally speaking, anything under a MERV 13 air filter should provide very efficient air purification in a home without impacting airflow.
A MERV 11 filter is the most popular choice for residential homes. This type of filter can remove most of harmful contaminants from a home environment, including smoke, dust mites, pet dander, mold, pollen, dust and smog.
Superior Particle Capture: MERV 11 filters excel at capturing smaller particles, including mold spores, fine dust, and pet allergens.
The MERV 11 air filter is the wrong choice for people who do not own pets and do not have any breathing trouble; this is because it can lead to restricted airflow. Air filters with higher ratings can also have negative effects on HVAC components.
For most homes, a MERV rating between 8 and 13 strikes the perfect balance between filtration, airflow, and cost. A MERV 11 filter, for instance, can last up to six months and offers excellent air cleaning without putting too much strain on your HVAC system.
Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.
MERV 11 and MERV 13 filters are specifically designed to trap and remove even the tiniest smoke particles from the air. These filters offer superior filtration capabilities and can help alleviate the negative effects of wildfire smoke on indoor air quality.
Sometimes, a MERV 11 filter may be too restrictive, particularly for older or smaller HVAC systems not designed to handle the increased pressure drop. If you notice that airflow has diminished or your HVAC unit is cycling on and off more frequently, these could be signs that your filter is too restrictive.
Pleated air filters can restrict airflow to some extent due to their denser construction and larger surface area. Non-pleated air filters generally have lower airflow resistance compared to pleated filters.
The higher-rated filter also captures up to 50 percent or greater of the smallest particles floating through the air. The primary benefit when comparing a MERV 11 vs. MERV 13 filter is that the latter includes stronger protection against airborne bacteria and viruses that spread through droplets in the air.
High-MERV filters increase the static pressure of your system, and if the ductwork is already marginal, this can cause the airflow to drop to a level where the temperature exceeds the furnace's limit.
' Hang a clean white sheet a few inches away from an air vent for a few minutes. If the sheet turns gray, the air filter is dirty and it's time to replace it. Keep in mind that dust around the air vents may also indicate a clog in the ducts.
Pleated air filters cost more than fiberglass but provide a longer filter life and higher efficiency.
The primary drawback of high MERV filters is that the pressure drop across them is too high, which can lead to reduced airflow and increased energy consumption in HVAC systems. This resistance may strain mechanical components over time, potentially causing failure.
The best filters have MERV figures of 13 or higher. But these can be expensive. There's another option for getting rid of the smoke smell. The answer is carbon.
Filter the air.
Use high quality air conditioning filters (MERV 11). This type of filter will capture most airborne mold spores.
The standard recommendation is to change your furnace filter every 1-3 months, depending on the type of filter you have and the conditions within your home. For instance, if you have pets or if someone in your household has allergies, you may need to change the filter more frequently to ensure optimal air quality.
If you don't change your air filter, it can quickly become clogged with dust and debris, preventing proper air filtration. This leads to a variety of issues for your HVAC system including system inefficiency, higher energy bills, inadequate air quality, and ultimately failure.
Filters rated MERV 8 are an excellent choice for homes without air quality concerns like allergies or respiratory health complaints. A MERV 11 filter, in contrast, provides enhanced filtration by capturing a greater percentage of smaller particles, including vehicle emissions, bacteria, and mold spores.
MERV 11 filters are more efficient than MERV 8 filters as they can capture smaller particles. They offer additional protection from pet dander, dust mites, auto-emissions, and lung-damaging dust. This is a good option for households with pets or those looking for even better air quality than the MERV 8 can provide.
These high-quality filters trap particles as small as one micron, including Legionella and humidifier dust. MERV 9 to 12 filters are the best filters that a residential HVAC system will accommodate without serious system modifications.
ASHRAE currently recommends using a minimum MERV 13 filter, which is at least 85% efficient at capturing particles in 1 µm to 3 µm size range. A MERV 14 filter is at least 90% efficient at capturing those same particles.