Having clean air in closed spaces in your home, workplace and in general is vital for our health. Although we cannot see them, there are many particles suspended in the air that can cause allergies and illness. So this tutorial will show you step by step how to quickly and easily build your own home air purifier with homemade hepa filter.
In this article we are going to tell you how to build a homemade HEPA filter and what its usefulness is.
air pollution at home
We often take for granted that the air in our home or workplace is less polluted than the air outside. However, outside this contamination is more diffuse, and in closed environments we are exposed to higher concentrations of toxic compounds such as:
- Persistent Organic Pollutants (POPs)
- Volatile Organic Compounds (VOCs)
- Bisphenol A (BPA)
- Perfluorinated Compounds (PFC)
- Molds, mites, bacteria, viruses, etc.
Home air purifiers are great for fighting air pollution and improving the quality of the air you and your family breathe every day.
What is a home HEPA filter
A HEPA filter is a retention system for volatile particles present in the air, Usually made of fiberglass. These randomly arranged fibers are so fine that they form a network that retains polluting compounds.
HEPA stands for “High Efficiency Particle Arrester”, which literally means “High Efficiency Particle Arrester” in Spanish, and they are also called absolute filters. They were created by the Cambridge Filter Company in 1950 for use in the military industry specifically to combat pollutants created when the atomic bomb was made.
Currently HEPA filters are used in all fields: food industry, electronics, pharmaceutical, chemical, in medicine in the operating room, air refreshment on the plane and even at home. In general, anywhere where higher air purity is required.
Although the fibers are between 0,5 and 2 microns in diameter, the randomly arranged meshes retain the smaller particles in three ways: When the air carrying the particles passes through them, particles stick to the mesh as they rub against the fibers. The larger particles collide directly with the fibers. Finally, diffusion, which is related to the random movement of the particles in the fluid, contributes to their adhesion.
How to make a homemade HEPA filter
Home air purifiers or refurbished machines can filter the air like those available at an appliance store, but it's cheaper. The materials needed for its construction are the following:
- You can use a bathroom exhaust fan or one used to ventilate closed rooms.
- HEPA 13 filter. They can be purchased as spare parts for vacuum cleaners and air appliances.
- Cardboard box with lid. It is recommended to use cardboard to make the purifier more durable.
- American tapes.
- Knives and/or scissors.
- Plug with cable and insulating tape.
Most HEPA filters They are made from continuous sheets of interlocking fiberglass blends. The most important factors to consider in this type of filter are the diameter of the fibers, the thickness of the filter and the speed of the particles. In addition, the filter has a rating (MERV rating) based on its ability to capture particles of a given size:
- 17-20: less than 0,3 microns
- 13-16: 0,3 to 1 micron
- 9-12: 1 to 3 microns
- 5-8: 3 to 10 microns
- 1-4: More than 10 microns
En este sentido, a HEPA 13 filter or Class H dust filter captures 99,995% of particles larger than 0,3 microns harmful to health. As such, they are best suited for filtering mold spores, dust mites, pollen, carcinogenic dust, aerosols, and pathogens such as bacteria and viruses.
On the other hand, its operation includes the capture of harmful particles through:
- Airflow interception: the particles rub against and adhere to the fibers of the filter.
- Direct hit: Large particles collide and get trapped. The smaller the space between the fibers and the air speed, the greater the effect.
- Diffusion: The smaller particles collide with other molecules, preventing them from passing through the filter. It usually happens when the air flow is slow.
How to choose the exhaust fan
An extractor fan is essential in an unventilated room and is an integral part of an air purifier. When choosing it, the following factors must be taken into account:
- Airflow must ensure adequate ventilation and extraction. Typically, this should be 6 to 10 times the total room volume per hour, although 4 to 5 is recommended in classrooms and libraries, 6 to 10 in offices and basements, and 10 in bathrooms and kitchens. 15 To calculate the extractor, you must multiply the m3 of the room (height x length x width) by the number of renovations required per hour. For example, a room of 12 m2 and a height of 2,5 m (30 m3) requires a flow rate of 120 to 150 m3/h, while an office of the same cubic meter requires a flow rate of 180 to 300 m3/h.
- The power of the extractor is usually between 8 and 35 W, and your choice will depend on the room in which it will be placed. In the kitchen, for example, more power is required due to the smoke generated when food is prepared.
- Noise levels should not exceed 40 decibels so as not to be annoying, but keep in mind that the higher the power, the more noise will be produced.
Tips for good air quality
In addition to building your own air purifier, it is recommended to follow a series of tips that will help improve the quality of the air in any room:
- Open windows regularly for ventilation. If there are no windows, there must be mechanical ventilation.
- Grow indoor plants that help purify and improve air quality.
- It removes excess moisture to prevent mold and mildew buildup, especially in areas like bathrooms.
- Prevents accumulation of dust and cleaning with chemical products, opting for more ecological products such as vinegar and baking soda.
I hope that with this information you can learn more about how to make a homemade HEPA filter.