Air purifiers effectively remove debris that can be found inside of a home. Selecting a home air purifier is often a matter of knowing what kind of purifier will work best inside of your house. There are numerous types of purifiers on the market, and getting to know a bit about these purifiers is the best way to become an informed shopper.

An ozonizer is a type of air or water purifier which uses ozone to kill bacteria and filter out a wide range of contaminants. Ozone itself is a form of oxygen, though much less stable than the common O2. Ozone is present naturally, mostly in the upper levels of the atmosphere, where it helps deflect ultraviolet radiation. Concentrations of ozone below the atmosphere can be a serious health risk, as ozone is highly toxic to humans and most other forms of life.

An ozonizer is also known as an ozone generator, and is sometimes mistakenly thought of as synonymous to an ionizer or ionic air purifier. An ozonizer does produce ionized particles, and an ionizer does produce trace amounts of ozone, but the two are not the same. An ozonizer creates ozone by charging the air with a burst of high negative voltage. An ionizer works under the same principle, but primarily produces ionized forms of molecules other than ozone.

In the United States, the ozonizer is most often seen in the context of air purification, where the use of "activated oxygen" is said to help attract dust particles and to kill ambient bacteria and molds. This use as an air purifier is also somewhat debated, as the levels of ozone emitted may or may not be harmful.

Contrary to popular perception, Air Conditioning (AC) is not about adding cool air to the room, but more about drawing heat away from it. The end result is a space with significantly less heat, which makes it feel cooler to occupants. Air conditioning takes advantage of the effects of evaporation, much like a swab of alcohol makes a person's skin feel cooler as the liquid evaporates. The alcohol doesn't lower the person's skin temperature, but rather draws away heat from the air as it turns to a gas.

An air purifier is any device used to remove mold, cigarette smoke, dust, pet dander and other pollutants and allergens from the air. The most popular type of air purifier for at-home use are High Efficiency Particulate Air (HEPA) filters. First used during WWII to capture radioactive dust, HEPA filters physically clean the air by "catching" the bacteria and pollutants as air passes through them. In order for HEPA filters to be efficient, all the air inside a room or building must enter through the filter.

Of course, cost will be a major issue when buying an air purifier. Installing a HEPA filter air purifier into an HVAC system may be worth the expense to some, but not to others. Besides the cost of installation or initial purchase, consider the ongoing cost of filter replacement.

In some cases, smoke ventilation can be achieved naturally with simple outgoing valves, but other cases may require electrical or hybrid technologies that can dissipate the smoke, toxic gases, and heat quickly and efficiently. Fresh return air is another crucial factor that is implemented in most smoke ventilation systems.

One of the latest evolutions within this field has been the emergence of hybrid smoke ventilation systems which utilize natural as well as mechanical means to function as an air purifier. 

Many air purifiers use High Efficiency Particulate Air filters, also known as HEPA filters, as their main filtration systems. The air purifiers that use HEPA filters reduce the amount of allergens, dust, and microscopic particles in the air. HEPA filters are known for their efficiency at capturing these airborne particles. A true HEPA air purifier is typically rated to remove 99.97% of airborne particles.

HEPA filters were invented to be used in air purifiers. Scientists in the Manhattan Project created the HEPA filtration system during the 1940s to remove radioactive particles from the air in labs. The filters have been improved to some degree over the years and are now used in purifiers in clean rooms, hospitals, and airplanes as well as homes and businesses.

There are two levels of HEPA filtration in air purifiers. First is the true HEPA or absolute HEPA level, which catches 99.97% of all particles that are 0.03 micron or larger. In the United States, these filters must go through a testing process to determine if they have this effectiveness level in order to be certified as a true HEPA filter. True HEPA filters typically have a serial number signifying that they passed the testing process. The second effectiveness level of a HEPA filter is the HEPA like or HEPA type filter. These either have not gone through the true HEPA testing or have not met its stringent requirements. These filters are typically 85% to 90% effective in removing air particles.

The filter in a HEPA air purifier is typically an accordion-folded sheet of HEPA quality filtration material. There are three main ways that this material in a HEPA air purifier catches particles. First, the larger particles are trapped, in much the same way that a strainer traps tea leaves but allows the liquid tea to pass through. This filtration process is called interception and it is common among most air filtration systems.