A thicker filter (4-5 inches) has more surface area and therefore leaves more room for air to pass through. However, there are many other factors at play, such as the size of the filter and the type of fan motor in your HVAC system. If your system only fits a 1- or 2-inch filter, a high MERV rating could be harmful. A 1-inch filter with less surface space will clog up fairly quickly and will need to be replaced much sooner than a coarser filter. The combination of a thin air filter with a high MERV rating can also restrict airflow to the point of impairing efficiency and causing excessive wear and tear.
Yes, pleated air filters restrict airflow to your HVAC system. However, you should be aware that all air filters will restrict air flow to a certain extent - it's a fact. What you need to worry about is simply finding the right filter for your unit and your overall system to ensure that you reduce the amount of pollutants in the air as much as possible. The short answer is that it can, but it's not really a problem except in extreme circumstances. Most modern HVAC systems have no problem working with higher MERV filters, so millions of homeowners rely on them.
The main risk of high-efficiency air filters comes from the fact that they are not modified for long periods of time. If you're aware of changing filters, you're unlikely to experience filter-related issues with your HVAC system. This also means that it is less restrictive to airflow, which helps the HVAC system operate more efficiently. So you will not only clean the air better, but you will also get much more airflow than standard one-inch ones. For example, a 13 MERV filter has a thickness of 1 inch.
Because the filter is thin and the MERV is tall, it reduces airflow in the duct system and quickly fills with particles and blocks airflow. But if the filter were thicker than 2 inches, it would have more surface area to leave more room for air to pass through and not restrict air flow. STAR Heating & Cooling technicians recommend pleated HVAC filters. Because of their construction, they do a better job of trapping dust and particles. When the filter material is folded into pleats, the filter has more surface area to capture dust. A flat surface filter has less surface area available to trap contaminants.
A flat surface filter can become clogged in a matter of days, depending on the amount of dust and dirt in your home. The trick is that the front area of the filter must be maximized to get the lowest possible filter pressure drop. Dust accumulation can cover the evaporator coil, causing temperature increases in the oven and overload of the air conditioner.Some air conditioning specialists have also noticed that thicker filters provide a better fit that does not allow unfiltered air to pass through. The air conditioner is also stressed by a dirty filter that slows down airflow, making the system work harder.
Of course, this can be very effective at stopping dirt, but it also serves to stop airflow to the unit. Different materials have much smaller pores, to allow the filter to remove contaminants, creating more resistance that wears the equipment. When you go shopping for an air filter, you'll notice there are plenty of options available. However, many of these are too thin - like a grandmother trying to learn how to use a mobile phone! Secondly, if left unchanged for too long, these filters can become so clogged up that they cause a pressure drop which can burn out your fan motor. The best way to protect your heater is by using pleated filters which are designed to trap dust particles more effectively than flat surface filters. I recommend changing your air filters every 1 or 2 months for maximum performance and energy efficiency.
Thicker oven filters - known as media filters - almost always perform better than cheaper one-inch filters. Different pleated air filters are designed taking into account different properties and results; this is important to remember when buying your own filter. In conclusion, thicker air filters do restrict airflow but this isn't necessarily an issue unless you're using an incompatible size or type for your HVAC system. If you're aware of changing filters regularly then you should have no problems with your HVAC system's performance.