Cows do not have four stomachs.
They have one stomach that is divided into four sections that have different digestive functions.
The rumen breaks down the grass that the cow eats. The next digestive phase occurs in the reticulum where the cud is produced. The cud gets burped back into the cow’s mouth where more chewing occurs. Then, the chewed cud is re-swallowed into the omasum that removes excess water from the food mass. Next is the abomasum where the food is finally digested. In a way, that delicious steak that we savor is nothing more than grass that has been processed into beef by the steer. Bovine digestion is just one example of how everything in life is a process. Using that same vein of thinking, even the air we breathe in our homes and workplaces undergoes a process with HVAC systems. The air does not change as dramatically as our grass into beef example, but before it’s heated by the furnace or cooled by HVAC cooling tubes, that air is first processed by the air filter. Depending on the MERV rating, air filters remove particulate matter from the air between 0.3 and 10 microns. The higher-rated HEPA filters are capable of capturing bacteria and microscopic allergens. Ironically, the purpose of HVAC filters is not to clean the air for your benefit. Their purpose is to keep the particulates from entering the inner workings of the HVAC where it can accumulate and affect the efficiency of the unit. Protecting your HVAC system is the real reason why it is important to change the HVAC filters regularly. Healthy air to breathe is simply a side benefit that the filters and HVAC systems make possible, just like beef and milk made by cows.