FLEXIT NORDIC KS3 Filter Sets – Original, High-Quality Alternative and Carbon
In this category you will find the original FLEXIT filter set (art. 120526) as well as carefully selected
high-quality alternative sets and a carbon filter set for the FLEXIT NORDIC KS3 ventilation unit.
All sets are manufactured in the correct size 275 × 133 × 96 mm to ensure:
very good indoor air quality
reliable and quiet unit operation
energy-efficient performance with low pressure drop
Our alternative (non-original) filters are produced with the same dimensions and filtration class as the originals
and fit precisely into the filter slots of the unit (275 × 133 × 96 mm).
Compatibility
These filter sets are designed specifically for:
FLEXIT NORDIC KS3
Do not confuse this unit with other FLEXIT Nordic or KS-series models – filter sizes and sets may differ.
Always check the model name on the nameplate and compare the filter dimensions
(275 × 133 × 96 mm) before ordering.
Available Filter Sets
1. High-Quality Alternative F7 / ePM1-55% Filter Set (Recommended)
A popular and cost-effective choice that keeps maintenance costs lower while maintaining high air quality.
Content: 2× F7 / ePM1-55% compact filters
Dimensions: 275 × 133 × 96 mm
Same filtration class as original F7 / ePM1-55%
Reliable fit and comparable filtration performance
Standard residential use:
High-quality alternative F7 / ePM1-55% set (2× filters) – same protection level as original
filters and very good balance between air quality, energy efficiency and price.
Areas with odour issues (traffic, industry, restaurants, smoke):
Carbon filter set (1× carbon supply + 1× regular exhaust filter).
Technical Data – Filter Specification
Filtration efficiency: ePM1-55% (ISO 16890)
EN class: F7 (EN 779:2012)
Filter type: Compact filters
Set content: 2 pcs (supply + exhaust)
Dimensions: 275 × 133 × 96 mm
Compatibility: FLEXIT NORDIC KS3
Original set number: 120526
Filter Installation
Switch off the unit and follow the FLEXIT user manual.
Remove old filters and insert new ones in the same position.
Observe airflow arrows (if printed) – they must point in the airflow direction inside the unit.
Ensure the filters sit firmly without gaps around the edges.
Close and lock the door properly for a good seal.
Replacement Interval
Typically 1–2 times per year in normal residential use.
Replace more often if:
you live in a polluted or high-traffic area,
there is construction work nearby,
there is a lot of dust or pets indoors.
Replace earlier if filters look dirty or the unit shows a filter alarm.
FAQ – FLEXIT NORDIC KS3 Filters
Which filters fit FLEXIT NORDIC KS3?
Original set: art. 120526 – 2× F7 / ePM1-55% compact filters, 275 × 133 × 96 mm
High-quality alternative set: 2× F7 / ePM1-55% compact filters, same dimensions
Compare with the product description (original set art. 120526).
Using the wrong filter size or class may cause:
air bypass (leakage around the filter),
poorer indoor air quality,
higher energy consumption and fan noise,
faster soiling of the heat exchanger and ductwork.
Stock and Delivery
Original FLEXIT, high-quality alternative and carbon filter sets for FLEXIT NORDIC KS3
are usually available from stock, ensuring fast dispatch and quick delivery within the EU.
New ACETEC EvoAir Ventilation Filters at FILTERS24
FILTERS24 is pleased to introduce a new range of high-quality compatible replacement filters for ACETEC EvoAir ventilation systems. The filters are manufactured to match the dimensions of the original filters, ensuring a precise fit and reliable ventilation performance.
ACETEC Filter Sets
Customers can choose between two filter options:
Standard filter set: 2 × F7 / ePM1 55% filters for supply and exhaust air.
Carbon filter set: 1 × F7 Carbon filter for incoming air and 1 × F7 / ePM1 55% filter for exhaust air. The activated-carbon filter helps reduce unpleasant odors, traffic pollution, smoke and selected volatile organic compounds (VOCs).
Compatible ACETEC EvoAir Models
The filters are suitable for a wide range of ACETEC EvoAir ventilation systems, including:
Read more »