Which Depth of HEPA Filter Do I Need? A Complete Guide
When it comes to selecting a
HEPA (High Efficiency Particulate Air) filter for your air filtration system, one of the most common questions we hear is:
“What depth of HEPA filter should I choose?”
The answer largely depends on the specific frame or housing you’re installing it into, as well as your system's airflow and pressure requirements. Whether you're designing a cleanroom, a DIY laminar flow hood, or upgrading an air purification unit, choosing the right depth is key to maximizing both filtration efficiency and energy performance.
Understanding HEPA Filter Depths: What It Means and Why It Matters
The depth of a HEPA filter refers to its physical thickness, which affects airflow resistance (pressure drop) and the surface area of the filter media. While all true HEPA filters meet the standard of capturing at least 99.97% of airborne particles down to 0.3 microns, the depth you choose can influence how well your system performs over time.
Generally speaking, there isn’t a drastic difference in filtration capability between various depths - but airflow performance and fan compatibility can vary significantly. A deeper filter may allow for greater surface area, which can reduce pressure drop and extend the filter’s lifespan, but it also requires a more powerful fan to push air through efficiently.
Choosing the Right Depth for Your HEPA Filter
If you’re using a pre-fabricated frame or system, your choice will likely be determined by the space available. However, if you're building your own setup, such as a DIY laminar flow hood or clean air enclosure for mushroom cultivation or electronics work, you have more flexibility.
In this case, we recommend selecting the filter depth based on your fan’s pressure and airflow specifications. Compare your blower’s CFM and static pressure ratings with the technical data sheets for each filter model (available on
our website on each product page) to find the best match.
Common HEPA Filter Depths by Application
At SPCB UK, we offer a wide range of
HEPA filter depths and sizes to accommodate most air filtration needs. Standard depth options are categorised based on the airflow type of the application:
- Standard depths: 68mm, 78mm, 88mm, 110mm, 115mm
- Custom depths available: Up to 125mm
- Standard depths: 150mm, 292mm
- Custom depths available: Up to 305mm
- Custom Spigot length
These offer maximum filter media surface area and are ideal for larger-scale air systems or extended use.
- Standard depths: 150mm, 292mm
- Custom depths available: Up to 300mm
HEPA Filters for Mushroom Growing & Mycology
HEPA filters are especially popular in the mushroom cultivation and mycology community, where clean air is crucial for sterile lab conditions. Since many amateur mycologists build their own flow hoods and sterile environments, there’s more flexibility in choosing a filter depth.
If you're part of this community and planning to build your own laminar flow hood, selecting the right fan-filter combination is essential. A mismatched system can lead to poor airflow or filter inefficiency. Be sure to check our technical specification sheets and match your blower’s capabilities accordingly - you’ll find this information on
our website
Custom HEPA Filter Sizes & Lead Times
We supply a wide range of standard and custom HEPA filter sizes and depths, typically with a lead time of just a few weeks. If you're not sure what you need, or if your application requires a non-standard depth or dimension, we're
happy to help.
Still unsure which depth of HEPA filter is best for your setup? Whether you're a DIY enthusiast, a cleanroom engineer, or simply looking for expert advice, we’re here to support you.
Contact our friendly team today for guidance, custom orders, or technical support.