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FLEXIT SPIRIT K2 / K2.1 (RER/REL)
FLEXIT SPIRIT K2 / K2.1 Filter Sets – Original, High-Quality Alternative and Carbon
In this category you will find original FLEXIT filter sets as well as carefully selected high-quality alternative sets and a carbon filter set for the FLEXIT SPIRIT K2 RER, SPIRIT K2 REL, K2.1 RER, K2.1 REL, K2 RER and K2 REL units. All sets are manufactured in the correct size 335 × 130 × 50 mm and match the original filterset Art. / Filterset No. 12767 (content: 2 × F7 / ePM1-55% compact filters) 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 (335 × 130 × 50 mm).
Compatibility
These filter sets are designed specifically for:
- FLEXIT SPIRIT K2 RER
- FLEXIT SPIRIT K2 REL
- FLEXIT SPIRIT K2.1 RER
- FLEXIT SPIRIT K2.1 REL
- FLEXIT K2 RER
- FLEXIT K2 REL
Do not confuse these units with other FLEXIT SPIRIT or K-series models – filter sizes and sets may differ. Always check the model name on the nameplate and compare the filter dimensions (335 × 130 × 50 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% alternative compact filters
- Dimensions: 335 × 130 × 50 mm
- Same filtration class as original F7 / ePM1-55%
- Reliable fit and comparable filtration performance
Order the high-quality alternative set here:
FLEXIT SPIRIT K2 / K2.1 Alternative Filter Set (2× F7 / ePM1-55%)
2. Original FLEXIT Filter Set – Filterset No. 12767
- Original filterset number: 12767
- Content: 2× F7 / ePM1-55% compact filters
- Dimensions: 335 × 130 × 50 mm
- Use: supply and exhaust air filtration with high efficiency
- Ideal if you prefer to use OEM parts from FLEXIT
Order the original FLEXIT set here:
FLEXIT SPIRIT K2 / K2.1 Original Filter Set (No. 12767)
3. Carbon Filter Set – Odour and VOC Reduction
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Content:
- 1× carbon filter for supply air (outdoor air)
- 1× regular filter for exhaust air (extract air)
- Dimensions (both filters): 335 × 130 × 50 mm
- Carbon filter on supply air side reduces odours and VOCs
- Regular exhaust filter protects the unit and exhaust ductwork
Recommended in urban locations, near busy roads or anywhere odour reduction is important.
Order the carbon filter set here:
FLEXIT SPIRIT K2 / K2.1 Carbon Filter Set
Recommended Solution for Most Users
-
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 – Original Specification
- Original filterset number: 12767
- Filtration efficiency: ePM1-55% (ISO 16890)
- EN class: F7 (EN 779:2012)
- Filter type: compact filter
- Dimensions: 335 × 130 × 50 mm
- Set content: 2 pcs (2× F7 / ePM1-55%)
- Compatibility: FLEXIT SPIRIT K2 RER / REL, K2.1 RER / REL, K2 RER / REL
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 SPIRIT K2 / K2.1 Filters (12767)
Which filters fit FLEXIT SPIRIT K2 / K2.1 (RER/REL) units?
- Original set: filterset no. 12767 – 2× F7 / ePM1-55%, 335 × 130 × 50 mm
- High-quality alternative set: 2× F7 / ePM1-55%, 335 × 130 × 50 mm
- Carbon set: 1× carbon supply filter + 1× regular exhaust filter, same dimensions
Why choose the high-quality alternative filter set?
- Same filtration class (F7 / ePM1-55%) as the original.
- Correct dimensions and good fit in the FLEXIT filter slots.
- Attractive price level with very good performance.
- Ideal if you want to keep regular maintenance costs under control while maintaining air quality.
When should I use the carbon filter set?
- If you want to reduce outdoor odours (traffic, smoke, restaurants, industry).
- To improve perceived indoor air quality and reduce VOCs.
- Especially suitable for city apartments and houses near busy streets.
How do I make sure I order the right set?
- Check the unit’s nameplate – it must be one of the listed K2 / K2.1 variants (RER/REL).
- Measure your existing filters (approx. 335 × 130 × 50 mm).
- Compare with the product description (original filterset no. 12767).
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 SPIRIT K2 / K2.1 are usually available from stock, ensuring fast dispatch and quick delivery within the EU.
