HEPA Filters - Wooden Frame or Metal Frame?

A question we are frequently asked is what is the difference between the HEPA filter panels that have a wooden frame and those with a metal frame? If you want to know a little more about the differences then, hopefully, this short article will help you. 

There are a number of differences, apart from the obvious one of different materials, but the most important thing to remember is that the filtration quality remains the same regardless of the frame construction.  So, whether the HEPA filter has a metal frame or a wooden frame the actual quality of the filtered air is no different.  So what are the differences between them?  Well, the most obvious one is price.  It won't surprise you to know that the cost of the metal frame is higher then the wooden frame as the cost of the raw material is higher plus it takes longer to fabricate the metal frame.  In addition to this, our metal framed HEPA filters are supplied, as standard, with a protective mesh covering both faces of the filter. The filter within a HEPA is delicate so the protective mesh is a real bonus as, if damaged, the quality of the air filtration can be greatly compromised.  You can have the protective mesh added to a wooden HEPA but it will limit your disposal options and, the added weight, does remove one of the benefits of the wooden frame.  The metal also gives a stronger frame so it is less likely to be damaged during transport or when being stored or installed.

So far we know that the wooden HEPA filters normally cost less than the metal but, generally speaking, aren't as strong and aren't supplied with a protective screen.  Another difference is weight; the wooden frames are considerably lighter than the metal frames so this could be something that you need to consider when choosing a HEPA filter.  If your air filter panel is large, and its position means that fitting could be awkward, then the weight of the filter panel should be considered as the weight of a metal HEPA filter can be over 50% more than the wooden alternative.

Now we know that the wooden frames cost less than the metal but aren't as strong or robust but they are lighter. Disposal of the used filter is another difference as the wooden framed filters can be incinerated (as long as they don't have the protective mesh screens) as the only metal parts are small staples that hold the frame ends together whilst the glue is drying.  Obviously the metal frame HEPA filters can't be incinerated although it is possible to recycle the aluminium frame.  The disposal depends upon your local disposal requirements as well as the dust that the air filter contains.

The final main difference is the environment in which the filter is being used. The metal framed HEPA air filters are recommended for damp environments or areas where there may be the risk of high moisture levels.  This doesn't mean that they can be installed in wet environments but are the better option should moisture be a possibility.  This is because the metal frames have a lower risk of microbial contamination and transfer as the metal frames are not going to absorb moisture unlike the wooden frames. Whilst this difference is the last mentioned, it is probably the most important as the whole point of installing a HEPA air filter is the high quality air filtration they offer.  HEPA filters are also known as absolute filters for a reason.  If you therefore use a wooden frame HEPA where moisture is possible then the benefits may be lost and you could even be in a worse situation.

So, which air filter frames should you use, wooden or metal?  As you are aware, these filter panels give very good filtration so whichever frame you decide upon, this isn't necessarily going to be compromised.  If the cost isn't the greatest deciding factor, then we would always recommend using the panel filters with the metal frames.  The overall strength of the filter panel makes it a very attractive option.  If moisture in the air is a consideration then, again, use the metal framed HEPA.  If weight or cost are deciding factors then, for us, it has to be the wooden frame.