Defro Filters
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House brandExtract filter size: 445x171x48 mmSupply filter size: 445x171x48 mmFilter class (EN779): M5+M5Filter quantity in a set: 2 filtersProtection levelFilter protection level indicates efficiency in blocking particles or contaminants, varying by standard and application.
BasicGeneral dust and particle filtration
Pollen and moldCaptures pollen, mold spores, and other allergens
OriginalExtract filter size: 445x171x48 mmSupply filter size: 445x171x48 mmFilter class (EN779): M5+M5(AC)Filter quantity in a set: 2 filtersProtection levelFilter protection level indicates efficiency in blocking particles or contaminants, varying by standard and application.
BasicGeneral dust and particle filtration
Odours and smokeFilters out smoke and unpleasant smells
Pollen and moldCaptures pollen, mold spores, and other allergens
OriginalExtract filter size: 445x171x48 mmSupply filter size: 445x171x48 mmFilter class (EN779): M5+M5Filter quantity in a set: 2 filtersProtection levelFilter protection level indicates efficiency in blocking particles or contaminants, varying by standard and application.
BasicGeneral dust and particle filtration
Pollen and moldCaptures pollen, mold spores, and other allergens
1-3 of 3Discover our range of replacement filters for your Defro ventilation unit, all made in the EU! Our selection includes high-performance M5 (ISO ePM10 55%) filters sets, designed to protect your system and improve indoor air quality. An optional version with activated carbon is also available. Whether you’re looking for original Defro filters or affordable house brand alternatives, all our options are quality-tested and fully compatible with Defro MVHR units. Model compatibility
This category includes filter sets compatible with all major Defro MVHR ventilation units, including:
- DRX V / OPTI series
To ensure the right fit, it’s important to know the exact model of your ventilation unit, as different models require different filters. You’ll find helpful tips on identifying your device in the FAQ section.
Filter types and what they protect against
Our replacement filter sets for Defro units are designed to ensure optimal air quality and system performance through dual M5 filtration and an optional activated carbon filter:
- M5 filters (ISO ePM10 55%) on the extract and supply side: ideal for capturing larger particles like pollen, mould spores, pet dander, and house dust.
- M5(AC) filter (ISO ePM10 55%) on the supply side: with a layer of activated carbon, which adsorbs a wide range of gaseous pollutants and odours.
Usage and maintenance
To keep your MVHR system running efficiently and your indoor air clean, we recommend replacing the filters every 3–6 months. However, this depends on your environment, if you have pets, or nearby construction.
To make the process easy, we provide step-by-step replacement instructions for each filter model. You can find them under the “How to change” tab on every product page.
Manufacturing quality you can trust
The original Defro filters are manufactured in Poland using advanced filtration technologies. Our carefully developed house brand filters are also made in the European Union by certified manufacturers. Both are produced with high-quality materials, under strict ISO 16890 standards to ensure high filtration performance and reliability.
Customer Reviews
Orginalus kokybiški filtrai, malonus aptarnavimas ir konsultacija
Mykolas TamulynasFacebook review
Patys geriausi atsiliepimai. Užsakytų filtrų grąžinimas, jei neteisingus užsakėte, galima grąžinti nemokamai.
Jūrate JokubauskienėGoogle review
Greitas ir kokybiškas aptarnavimas. Geras kainos/ kokybės santykis. Rekomenduoju!Ingrida BaltuškienėGoogle review
Pirkome rekuperatoriaus filtrus internetu, viskas buvo sklandu, puslapiu patogu naudotis, prekes gavome itin greitai.Monika BijeikytėGoogle review
Super aptarnavimas, nuoširdžiai rekomenduoju apsilankyti!!!
Pavel KoliatoFacebook review
Patenkintas dėl to kad įmonė labai operatyviai ir sklandžiai veikiaAnatolij DrozdovičGoogle review
Need Help? Start Here.
We’ve gathered answers to the most common questions about our products and services. If you can’t find an answer here, please contact us directly.
Does Defro make MVHR units, or only heating equipment?
Defro is best known as a manufacturer of biomass boilers and fireplaces, but its range also includes the Defro AIR line – residential heat recovery ventilation units, often installed in the same house alongside Defro heating equipment. Defro AIR filters are measured and classified the same way as filters for other manufacturers' MVHR units, so identifying the model from the label on the unit or measuring the filter directly both work equally reliably.
What filter classes are used in the Defro AIR unit?
Defro AIR units typically use two-stage filtration, following the industry-standard M5/F7 combination:
- a coarser filter that protects the heat exchanger from dust and debris
- a finer F7-class filter for the supply air stream
When buying filters, it's also worth checking the ISO 16890 class (e.g. ePM10 or ePM1), which today is often listed alongside the older EN 779 designation in the user manual.
Can I replace the Defro AIR filters myself, without a technician?
Yes, the Defro AIR filter compartment is designed for front or side access, and removing the old filter and fitting a new one usually requires no tools. Simply unscrew the cover or release the latch, pull out the old filter, check its condition, and insert the new one in the same orientation (arrow pointing in the direction of airflow). If you're unsure of the exact steps for your specific model, it's worth checking the manufacturer's user manual – the procedure is similar across all Defro AIR models.
How often do Defro AIR filters need to be changed, and is it worth buying a year’s supply at once?
The usual recommendation is to check the filters every 3 months and replace them when you notice reduced airflow or increased noise – typically 2–4 times a year, depending on outdoor air pollution and the number of occupants. Buying a year's supply (2–4 sets) at once is a convenient way to make sure you're never caught without a filter at the wrong moment, and buying several sets together usually works out to a lower price per unit than buying one at a time.
Is there an activated carbon filter option if the Defro AIR unit is installed next to a biomass boiler?
When a Defro AIR unit is installed close to a biomass boiler or fireplace, the outside air intake sometimes picks up a smoky smell. In that case, a supply filter with an activated carbon layer helps absorb some of the volatile smoke particles and odour before the air enters the rooms. This filter is fitted as an additional stage alongside the standard M5/F7 filter set, not in place of it, so the main particle filtration is not compromised.
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