Flexit Nordic S2/S3 filters

We supply filter sets for Flexit's most widely used residential lines — Nordic S2/S3, S4 and CL2/CL3/CL4, UNI 2, UNI 3 and UNI 4, Econordic W4/WH4 and SL4R — common across Norway and the other Nordic countries. For Nordic and UNI units you can choose between Flexit originals and our house brand. The model designation is usually printed on the label on the front panel.

Our house brand Flexit sets are F7+F7 — a fine F7 (ePM1) filter on both the supply and extract side — and the Econordic W4/WH4 and SL4R originals are F7+F7 as well. That protects the heat exchanger and gives strong filtration of fine dust and pollen in the incoming air.

You can return it. We accept returns of unused, undamaged filters within 30 days of delivery. To avoid the situation altogether, check the exact model name on your Flexit unit (e.g. Nordic S3, UNI 3, SL4R) before ordering, or measure the old filter in millimetres – length, width and thickness – and compare it with the dimensions in our catalogue. If you're unsure, send us the model name or a photo of the label and we'll confirm the right filter set.

Switch the unit off before opening the filter compartment. On Flexit MVHR units the filters are usually reached by opening the front cover – often just releasing the latches by hand is enough. After removing the old filter, check the airflow direction arrow on the new filter's frame and insert it in the same orientation, then close the cover, switch the unit back on and reset the filter timer if needed. You'll find the exact steps for your model (e.g. SL4R) in the unit's user manual.

Yes, we accept wholesale orders:

• for apartment building homeowners' associations
• for managers overseeing several buildings
• for landlords with multiple Flexit units

A larger discount per unit applies above a certain quantity. Send us the models of your units and the quantity needed – we'll prepare a consolidated order with enough filters for every MVHR unit in the building.

Flexit heat exchangers are optimised to work in sub-zero temperatures, so during the cold season the unit often runs at a higher and steadier airflow to maintain heat recovery efficiency. Because of this more intensive operation, filters can fill up somewhat faster than in the warmer months, so it's worth doing an extra check in the middle of winter rather than waiting for your usual schedule. In Norwegian this is called “filterbytte” – filter changing – and the term is often mentioned in Flexit user manuals as well.