DIY filter box / filter case for controlled residential ventilation

Hello everyone,

There are already some DIY projects for controlled residential ventilation filter boxes on the internet. Since the supply air filter in my system will need to be replaced soon, I want to start the project. Hazelnut pollen is flying like crazy and alder also seems to be making an effort. I would like to keep both outside.

Unfortunately, the pictures from other forums are now mostly only accessible as Google thumbnails. Starting today, I will probably begin with the project.

Everything is supposed to be squeezed in here somehow:



Updates to follow.

Available is:


I'll go to the hardware store tomorrow.

Hi , have you made any progress with your project?

Hi , have you made any progress with your project?

Morning, I have – it just took a long time! There’s always something. But in the meantime, the filter change indicator arrived, so I found some motivation after all.

It looks like this and has been hanging since yesterday.



I’ll gather my detailed pictures and write a bit about the development. But so far, it seems to be working and largely airtight. At least, I don’t feel any drafts.

So far, the energy consumption of the system is 10% (3W) higher than before the intervention. But that’s probably because the old clogged filter is still inside and I haven’t had time to remove it.

Today, for the first time in a long while, I cleaned the filters in the supply air (!) valves, and in the basement I encountered quite a few dead flies. I clean the exhaust air valves regularly – I’m lazier when it comes to supply air.

I immediately got worried that my filter construction might not be as good as I thought.

However, during the inspection, I didn’t notice anything unusual. On the dirty side, it is quite dusty and the filter is dirty. Also, on the dirty side, a few insects were crawling towards me.




On the clean side, however, there are absolutely no deposits, dirt, or anything else to be seen. So far, I am very satisfied with my work. It actually seems to have become relatively tight. The flies have probably been lying there for quite some time.

The flies have also caught my attention here. I wonder if they come from the condensate trap?