For cleaner air, you'll need a filter with a MERV rating of at least 6. For most homes, the best HVAC filters for summer are cotton or polyester pleated filters of MERV 8 to 10. A MERV 8 filter traps almost 85% of particles down to 3.0 microns.
The abbreviation stands for Minimum Effective Reporting Value. In other words, it's a measurement showing how small the holes are in the filter. The higher the MERV number, the smaller the holes, and the less that can pass through. Ultimately, this is what makes MERV 14 filters not a good choice for home use.
This means your system will use an unnecessary amount of energy during the summer when rates are already higher. As we mentioned above, it's important to change your furnace filter to keep your system running as efficiently as possible, but it will also make your cooling system last much longer.
Summer: Managing Dust and Humidity
Filter Recommendation: Continue using a higher MERV rating filter, such as MERV 11, to handle the extra dust. If humidity is a concern, consider a filter with antimicrobial properties to prevent mold and mildew.
For most homes, a rating of MERV 8-13 is a good start to keep your air healthy.
For households working with tight budgets, MERV 8 filters offer cost-effectiveness and minimal upkeep requirements. Superior particle capture and enhanced air quality come with MERV 11 filters, making them suitable for dwellings with pets, allergies, or high pollution.
A common question among homeowners is, “What is the max MERV for a home?” Generally, a MERV rating up to 13 is typically the upper limit for most homes. Using filters with a MERV rating higher than this can be too restrictive, potentially impeding airflow and straining your HVAC system.
For cleaner air, you'll need a filter with a MERV rating of at least 6. For most homes, the best HVAC filters for summer are cotton or polyester pleated filters of MERV 8 to 10. A MERV 8 filter traps almost 85% of particles down to 3.0 microns.
ND256, ND512, ND1000, and ND10000 filters are great for creating long exposure photography when shooting in bright light or in harsh sunlight.
As mentioned, the three main classes are excitation filters, emission/barrier filters, and dichroic filters, but filters can also be categorized as SP, LP or BP. Commonly, filters are referred to by these characteristics and the wavelength where they switch between transmission to reflection.
Running the fan continuously helps improve air filtration, as it continuously draws air through the filters, trapping and removing contaminants. This can lead to better indoor air quality and a reduction in respiratory irritants.
You'll often find the filter in a slot or compartment within the air handler itself or near where the return air duct connects to the system. And that means, of course, that both systems share the same filter. So, air will flow through your system's air handler regardless of whether you're heating or cooling your home.
MERV 13 Air Filters
Filters with higher ratings are intended for healthcare and laboratory environments with excellent air quality and HVAC systems that can handle highly efficient filters. Using a filter above MERV 13 in a home is unnecessary and can restrict airflow and damage the HVAC system.
Scenarios Where MERV 11 May Be Considered Too Restrictive
Sometimes, a MERV 11 filter may be too restrictive, particularly for older or smaller HVAC systems not designed to handle the increased pressure drop.
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.
Use ND filters to help you control the light in your entire scene. Use a graduated ND filter as needed to balance the light across your scene. Use a polarizing filter – especially when you have water in your scene. Always use a sturdy tripod.
Hydrogen Alpha / H-Alpha / Ha Filters
H-Alpha filters capture a very narrow band of sunlight and allow you to view details on the solar surface beyond sunspots. These electronic filters are often tuned to allow viewing of either solar prominences or chromosphere details.
The 3-stop and 6-stop are by far the best performers and at the same time allow for the greatest versatility. If you're shooting golden light (sunset, sunrise, twilight etc.) the 6-stop will always be your go-to ND for 2-4 minute exposures, with the 3-stop coming into play after you've hit the 4 minute mark at ISO 100.
Pleated filters can restrict airflow slightly more than non-pleated ones, but they balance filtration and airflow. Choosing the right MERV rating (between 8 and 13) ensures your system gets proper airflow while still effectively filtering the air.
What Is the Most Common Size of Air Filter for a House? The most common size air filter for a house is usually 20 x 20 x 1, but this can vary depending on the specific HVAC system installed.
The higher the MERV rating, the better the air filter is at removing particles. Cheap air filters typically have a low MERV rating of 6 or less, while expensive air filters can have a MERV rating of up to 13. This means that they can remove much smaller particles, like bacteria, viruses, and mold spores, from the air.
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.
Air filters with higher efficiency ratings may do a better job clearing the air. Still, they'll also force your HVAC system to work harder, resulting in performance challenges and higher energy bills.