Ionisation and bipolar air cleaning technologies are gaining popularity

The popularity of self-charged, nanofiber, and anti-microbial air filters is increasing due to their ease of installation and compatibility with various spaces. Tushar Kalra, Founder of Air Exchange Solutions, discusses the types of air filters in air conditioning systems and their efficiency and applications.

What are the different types of air conditioning filters and their specific applications in various systems?

The efficiency and application of air conditioning filters depend on their design and the environment they are used in. Polyester washable filters are used in domestic air conditioning systems like hi-wall/split, cassette, and standalone air purifiers to capture coarse dust, dirt, and solid particles, primarily to protect the unit’s internal components. Media filters are used in HVAC systems like deductibles, fan coils, air handling, and treated fresh air units. They are designed from synthetic, non-woven polyester with pleats and capture smaller particles like PM10 and PM2.5 pollutants, mould spores, and pet dander. They come in various MERV ratings.

HEPA filters (High-Efficiency Particulate Air) are used in hospitals, cleanrooms, and other environments where air purity is important. HEPA filters, made from fibreglass or ePTFE media, can remove up to 99.995 per cent of particles as small as 0.1 micron/MMPPS (Most Penetrating Particle Size). HEPA filters frequently pop up in standalone air purifiers and centralised air conditioning systems, although they are not employed in standard domestic HVAC systems due to airflow restrictions.

Activated carbon filters are widely utilised in HVAC systems and air purifiers to remove odours, gases, and volatile organic compounds (VOCs) from the air. They work differently from particulate filters by adsorbing gas-phase pollutants onto the activated carbon surface, providing a comprehensive solution to air purification challenges. ESP Filters (electrostatic precipitators) are used in HVAC systems for residential and commercial applications. They attract and capture particles using an electrostatic charge, offering efficient performance without significantly restricting airflow and effectively capturing particles of various sizes.

How do HEPA filters compare to standard filters in particle removal efficiency and certification?

High-efficiency particulate air filters (HEPA filters) are renowned for their superior performance in removing fine particles and allergens compared to standard filters. HEPA filters offer up to 99.995 percent efficiency, while standard filters have up to 50 percent efficiency on the same-sized particles. HEPA filters are certified according to EN 1822:2009 and ASHRAE standards.

What factors ensure optimal performance and energy efficiency when selecting an air filter?

Performance, energy efficiency, and cost-effectiveness are major factors. Higher MERV (Minimum Efficiency Reporting Value) ratings indicate better performance on smaller particles like PM2.5 and PM1.0. However, higher-efficiency filters can restrict airflow, check pressure drop specifications, and ensure compatibility with your HVAC system design to avoid overworking and reducing efficiency.

Filter maintenance and replacements improve long-term performance and efficiency. Some filters, like HEPA and electrostatic filters, may require fewer frequent replacements, and regular maintenance is essential to ensure the filter’s longevity and effectiveness. The frequency of filter cleaning or replacements ensures optimal performance.

Higher-quality filters may offer better performance and efficiency, but cost should be weighed against potential energy savings, replacement costs, and improved air quality. If sustainability is a concern,  looking for environmentally friendly filters that do not emit harmful or toxic products becomes a viable choice.

How often should air filters in air conditioning systems be replaced or cleaned to maintain proper air quality and system efficiency?

Regular cleaning or replacing air filters in air conditioning systems maintains air quality and system efficiency. The timing depends on the filter type, environment, and manufacturer recommendations. Residential and light commercial filters should be checked monthly and replaced every 1 to 3 months, while commercial and industrial filters should be inspected more frequently. Follow the filter OEM’s guidelines and replace or clean filters when they reach the recommended final pressure drop. This ensures the overall maintenance of filters based on actual performance.

What advancements in air filter technology are taking place to address air quality concerns?

Indoor air quality concerns are increasing the resiliency of self-charged, nanofiber, and antimicrobial air filters. Active air cleaning technologies like ionisation and bipolar are gaining popularity due to their ease of installation and compatibility with various spaces.