Pharmaceutical, medical, and electronic industries require clean rooms, which create a controlled dust-free environment without contaminants and airborne particulars. They rely on ULPA and HEPA filters to achieve this air quality, but that’s not their only use.
ULPA and HEPA filters are also found in HVAC systems to improve the air quality in homes. If this is your first time changing or installing the air filter in your HVAC system, you’re probably not sure which one to use.
Although HEPA filters are popularly considered the better option, the right filter for you depends on your budget and intended use. Keep reading for a complete comparison of the ULPA and HEPA filters to find out which one suits you best.
Ultra-Low Penetration Air (ULPA) filters are used to remove the risk of contamination by airborne particles and pathogens that may ruin the air quality. They can remove at least 99.999% of bacteria, airborne particles, mold, dust, and pollen from the air.
It can even capture ultrafine particles, which are only 120 nanometers in size. These filters are also able to remove insecticide, dust, smog, rosin smoke, tobacco smoke, and oil smoke from the air, along with carbon black to some extent.
Most standard air filters rely on “sieving” to physically block particles, which doesn’t work on ultra-fine particles. ULPA filters use four techniques to complete the cleaning process: sieving, diffusion, inertial impaction, and interception.
Instead of a simple net, the filter media in a ULPA filter consists of a large web of randomly-arranged fibers. Air passes through the filter’s dense fiber web, and almost all contaminants are stuck to the fibers, cleaning the air.
Low-porosity fibers may slow down the filtration speed, but the result is much finer air quality. The porosity of fibers in an air filter is measured in pores per inch.
- Lower energy consumption
- Wide applications
- Better operator and environmental protection
- More expensive
- Shorter filter life
- Restricted airflow
High-Efficiency Particulate Air (HEPA) filters are also used for contamination control in hospitals, vehicles, and homes. They can remove somewhere between 99.97% and 99.99% of airborne particles, but they must be smaller than 0.3 microns in size.
These filters are tested by passing particles sized 0.3 microns through them, as these are the most difficult to capture. HEPA filters are better at capturing smaller particles, such as viruses, which are sized 0.1 microns. The behavior of smaller particles is easier for HEPA filters to catch.
HEPA filters are unlike any air filter you may have used before since they have a pleated mechanical configuration. Plus, their thickness is above average, which allows them to capture the smallest airborne particles and pathogens.
The pleats on HEPA filters create a mat of randomly-arranged fibers, which hold onto all particles passing through the filter.
- Readily available
- Prevents allergies and asthma
- Produces no byproducts
- Can’t remove every particle
- Difficult to clean
- Requires frequent replacement
Which One is Better for You?
By description, ULPA filters seem like they perform much better than HEPA filters, so why do most industries still use HEPA? That’s because the description of these filters can be somewhat deceptive.
ULPA filters are able to collect particles in the 120 to 400 nanometers range, which is why it’s only ideal for specialized applications. That includes medical laboratories and microelectronics manufacturing, where they may need to remove particulars from a clean room.
On the other hand, HEPA filters have a much broader application since they’re ideal for biological uses such as healthcare. The reason HEPA filters work so well in hospitals is that they can capture particles smaller than 0.3 microns, such as sweat and saliva.
Most viruses are within that range as they are typically 0.1 microns. This allows HEPA filters to rid the environment of all harmful contaminants. Plus, ULPA filters have certain disadvantages to know about, including:
It’s worth noting that airflow is the main way to differentiate between HEPA and ULPA filters. Since ULPA filters are much more restrictive, you can’t simply swap one out for a HEPA filter. In fact, the filter media in ULPA filters is so dense that it can even block airflow by 20% to 50%.
Aside from lowering the pressure, this also lowers the air changes per hour (ACH), which is a key metric in the functioning of an HVAC system. ULPA filters bring the ACH to a dangerously low level and worsen the air quality of the environment.
Unfortunately, ULPA filters are also more expensive than HEPA filters, which is why the latter is the more commonly used option. The filter media in ULPA filters is denser and more difficult to produce, making them approximately 35% more expensive.
To design a ULPA filter with the same ACH as a HEPA filter, manufacturers would need to make a bigger filter to compensate for the restricted airflow. This would also require a more powerful blower and a larger and pricier filter system overall.
Aside from being initially expensive, ULPA filters also have a short lifespan, which means you need to buy them more often. In fact, they only last five to eight years, while HEPA filters in the same application would last about a decade.
When using ULPA filters, you may also need to invest in pre-filters to protect the finer filters in the system. That’s an additional cost to consider when opting for ULPA filters.
When reading how a ULPA performs, it may seem obvious to throw away your HEPA filter and invest in a ULPA one. But there are many reasons why that wouldn’t work, making HEPA filters the more commonly-used option today.
For a ULPA filter to deliver the ideal ACH, its entire filter system would have to be larger and more expensive. Plus, ULPA filters restrict airflow and don’t last long enough, so it’s best used in specific applications.
If you’re looking for an air filter to install in your HVAC system at home, HEPA filters are efficient, affordable, and readily available.