Why is it important to clean the filters in the recuperator and what are the filters for

Heat recovery units (HRVs), i.e. mechanical ventilation systems with heat recovery, are becoming increasingly popular in modern buildings. The main advantages of heat recovery ventilation are improved indoor air quality and energy savings. One of the key components of every heat recovery unit is the filter, which plays a crucial role in the correct operation of the system.

Regular cleaning and maintenance of filters are essential to ensure high efficiency, reliable operation and long service life of the ventilation system.

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What functions do filters perform in a heat recovery unit?

1. Air purification

Filters remove contaminants from the air supplied to indoor spaces. These include dust, pollen, mites, allergens and microorganisms. As a result, the air inside the building is cleaner and healthier to breathe.

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2. Protection of the heat exchanger

The heat exchanger is the heart of the heat recovery unit, where heat is recovered from the extracted air. Filters protect the exchanger from contamination, which could otherwise reduce its efficiency and increase energy consumption.

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3. Protection of ventilation ducts

Filters prevent dirt and dust from settling inside ventilation ducts. This significantly reduces the risk of mould and bacteria growth, which can develop in humid environments.

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4. Improved energy efficiency

Clean filters ensure free airflow through the system, minimising resistance and lowering fan energy consumption. Clogged filters increase system load, leading to higher electricity use and potential failures.

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How often should filters be cleaned?

The frequency of filter cleaning depends on several factors, including the type and model of the heat recovery unit, the level of outdoor air pollution, and operating conditions.

As a general rule:

• Filter condition should be checked every 3–6 months
  
• Filters should be cleaned or replaced at least once every six months
  

In areas with high air pollution, such as city centres or industrial zones, filters may require more frequent servicing.

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How should filters be cleaned?

Regular filter cleaning is essential to maintain their effectiveness and ensure correct system operation.

• Filters should be inspected every 3 months to assess contamination and airflow resistance.
  
• In most cases, filters should be cleaned every 3–6 months. In highly polluted areas, cleaning may be required every 2–3 months.
  
• Filters can be cleaned using a vacuum cleaner (to remove larger particles) or by gentle washing with water and mild soap, provided the filters are reusable and the manufacturer allows this.
  
• Before reinstalling, filters must be completely dry.
  

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How often should filters be replaced?

1. Standard G3/G4 filters

These basic filters should be replaced every 6–12 months. Their primary function is to capture larger dust and dirt particles.

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2. Fine filters F7/F9

Higher-efficiency filters that capture finer particles should be replaced every 6–12 months. In areas with heavy air pollution, replacement may be required more frequently — even every 3–6 months.

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3. Carbon filters

Carbon filters, used to remove odours and chemical pollutants, are typically replaced every 6–12 months, depending on usage intensity and pollution levels.

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Factors affecting how quickly filters become dirty

Several factors influence filter contamination and should be taken into account:

1. Location

In areas with high pollution levels, such as urban centres or industrial areas, filters clog faster and require more frequent maintenance.

2. Seasonality

During periods of increased pollen levels (e.g. spring), filters may need more frequent cleaning or replacement.

3. Usage intensity

In homes with many occupants or in public buildings, the system operates more intensively, increasing maintenance frequency.

4. Indoor air conditions

If there are pets, smoking, or dust-generating appliances (e.g. fireplaces) in the building, filters will wear out more quickly.

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Summary

Regular cleaning and replacement of filters in a heat recovery unit are essential to maintain system efficiency, durability and indoor air quality.

• Standard filters should be cleaned every 3–6 months and replaced every 6–12 months.
  
• Fine and carbon filters require more frequent inspection and may need replacement every 6–12 months, depending on conditions.
  
• Checking filter condition every 3 months allows for quick response to contamination and helps keep the system in optimal condition.
  

Remember: regular maintenance is an investment in health, comfort and energy savings.