Is it OK to stack air filters?

Can You Stack Air Filters? Do not stack multiple smaller air filters on top of one another to fit them into a larger air handler. Installing multiple 1” air filters in a 2” slot, for example, can cause costly damage to your AC unit, as residential furnaces are not equipped to handle this level of airflow restriction.

Can you layer air filters?





In some cases, your intake vents or air handler vents have a filter depth greater than an inch. Because 1 inch air filters are the most common, some homeowners may think it’s okay to layer 1 inch air filters to fit a 2-, 3-, or 4-inch air filter slot. It’s not recommended to do this.

Can I stack 4 1 inch air filters?

If you measure the filter slot, and it’s large enough to accommodate the thicker filter, then you can use it. However, if the slot is less than 4 inches wide, you’re stuck with using that thickness. What you can’t do is stack filters — use only one.

Can you stack MERV filters?

No, you can’t stack 2 inch filters together, because a four inch filter will actually have the correct amount of area and resistance to air flow, whereas a 2 inch filter placed twice will have double the 2 inch filter’s resistance to air flow, just as if you were adding resistors in series.

Can you put two filters in HVAC?

Can I Stack Two 1 Inch Air Filters? You should never stack air filters. Even though you might think that the air would get cleaned a bit better if you have two filters side by side that is not exactly the case. It would become a lot harder for the HVAC system to suck in enough air.

Are 4 air filters better?





The 4-inch thick air filter has a definite advantage over the 1” filter in terms of longevity, airflow and maximum filtering potential. Thus, if it fits your furnace, then a 4-inch air filter is better than a 1-inch air filter in regards to improving air quality.

Are thicker air filters better?

Most air filters are 1 inch thick, but some systems can accommodate filters 2 to 5 inches thick. In our tests, we found that the thicker the filter, the better it works and the longer the replacement intervals. That means it’s better for you and for your heating, ventilating, and air conditioning (HVAC) system.

Can an air filter be too thick?

If you get a filter with pleats that are too thick, your filter could get dirty quickly. Thus, making your AC unit work harder than it needs to. A good benchmark to follow when considering MERV ratings is that if it’s more than 13, the pleats are most likely too thick for your filter.

Do pleated air filters restrict airflow?

Because they restrict airflow to your HVAC system. Pleated, high-MERV filters definitely capture a lot of pollutants, but they also restrict the movement of air into your blower or furnace. As a result, the fan has to work harder to heat and cool your home, reducing efficiency.

Can a furnace have two filters?



If you have more than one HVAC system, then you’ll typically have more than one air filter in your ceiling. However, it’s also important to note that some HVAC systems, especially larger ones, may have more than one air filter and can even require different sizes in different locations.

Does every return vent need a filter?

In general, it is recommended to have an air filter in every return vent (as long as you choose the one of the right size and thickness). The filters will improve the air quality in your house and will protect the HVAC equipment from dust, pollen, pet dander, and hair.

Are 2 inch filters better than 1?

Well, the thicker the filter the less restrictive it is. This contributes to a better flow of purified air. This means that 2-inch furnace filters allow a better flow of air than 1-inch filters.

Why do I have two air returns?



Having two air return vents allows you to seasonally control which air is returning to the HVAC system. In older homes, this may not be an option. The theory is that in the Summer cooling season, you want to be circulating warmer air back through the HVAC system to be cooled.

Can you have too many air returns?

Having several return vents (ideally one in every room, but even two or three is better than just one) creates consistent air pressure. If you have one return vent, your home is fine. Keep the doors to each room open so air can properly circulate.

Does every room need a cold air return?

While it is a myth that air return grilles are required in each and every room in the house, it is definitely necessary to have more than one of these grilles installed at strategic places in the house. The most important place to have these would be the bedroom.

What happens if there is not enough return air?

If there is not enough return air available, your HVAC system will not heat or cool properly. They must be properly sized — Return air ducts must be large enough to carry a sufficient amount of expended air back to your furnace, air conditioner, or heat pump.

Can a return duct be too short?



If the return duct is too small, there are an inadequate number of return grilles or they are undersized, it can’t return enough air to recirculate back into the system. The average duct system has 25% less return air than required according to National Comfort Institute.

How many return air vents should I have?

Ideally, every room except the kitchen and bath should have its own return air grille. At the very least, each level of the house should have one. Even so, many homes were built with just one or even no return ducts in an attempt to cut costs.