MVHR Filters for Zehnder CA 155

[ectoplasmosis]

I have just renovated a Victorian semi, and fitted a Zehnder CA 155 WM MVHR unit.

 

I'm looking to upgrade the standard 'G3' grade filters, but can't find anything finer than G4 for the CA 155 model. 

 

Would upgraded filters from any other model fit? If not, is there a way of modifying/making custom filters? My daughter and I have asthma, so it would be great to fit F7 grade or better filters to deal with PM1 particles.

[Gareth J]

There are some M5 filters listed on eBay,

https://www.ebay.co.uk/itm/356389666853?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=EFCv-lXXRCa&sssrc=4429486&ssuid=bl7oVt0pRnS&var=625385974528&widget_ver=artemis&media=COPY

 

The company claim to make them themselves so might be worth asking if they can make something bespoke.

 

I've not used the company before, but was about to try a replacement set from them.

 

As an aside, do you ever notice your unit boosting itself due to humidity? Apparently it should but I've either not noticed it or mine doesn't. What it uses for parameters and what makes it's humidity boost "smart" is all very vague. I doubt it's particularly smart somehow.

[Chanmenie]

How about this and cut to size yourself 

 

https://www.ebay.co.uk/itm/145921349462?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=_jYh3d7qRwK&sssrc=4429486&ssuid=RFd2NvYhQZC&var=&widget_ver=artemis&media=COPY