These days, air quality has once again become a central topic — and one of the major public health concerns. It’s a shame how quickly we forget about this problem as soon as warmer days arrive, but today I won’t dwell on that seasonal amnesia. What’s been occupying my thoughts lately is how we can protect ourselves right now, while thick smog makes every breath feel heavy and long-term decarbonization measures and the transition to cleaner energy sources are still waiting to show tangible results.

You’ve surely noticed that more and more homes now have air purifiers. Perhaps one is quietly humming in your own living room at this very moment, releasing air that seems cleaner than what we see outside (and yes — these days, we really can see the air around us). But is that feeling of cleaner air just an illusion, or real relief for our lungs? It turns out the truth lies somewhere in between.

When I started researching how effective air purifiers actually are, I quickly realized that everything comes down to one essential element: the quality of filtration. And that inevitably leads to HEPA filters, which have become a synonym for reliable air cleaning.

HEPA filters are made from a dense network of fibers that capture 99.97 percent of particles as small as 0.3 microns — the most persistent and penetrating ones, those capable of traveling deep into the lungs and bloodstream. What’s particularly interesting is that HEPA technology wasn’t originally designed for home use. It was developed in the 1940s to protect against radioactive particles, and only later made its way into households, becoming the “gold standard” in air purification, as the IQAir website explains.

Over time, advanced versions emerged as well — such as HyperHEPA filters, which capture ultrafine particles down to 0.003 microns, one hundred times smaller than PM0.3. This means they can remove what was once considered nearly impossible to trap: viruses, nanoparticles, and the finest combustion residues.

Photo-illustration: Pixabay (Maruf_Rahman)

However, even the best filter doesn’t mean much if the air simply bypasses it. Many purifiers suffer from poor sealing, allowing air to slip around the filter and carry pollutants back into the room. Devices that solve this issue with airtight housings perform noticeably better in real-world conditions.

Another important thing to understand is that HEPA filters remove particles — but not everything we perceive as “air quality.” They don’t eliminate gases, odors, VOCs, smoke, or chemical fumes. For that, you need activated carbon — and not just a thin decorative layer, but a substantial amount capable of genuinely absorbing irritating molecules.

What I would personally avoid are devices that promise “miracle solutions” — ions, ozone, magical UV lights. Ionizers mostly just force particles to stick to surfaces instead of removing them. Ozone is directly harmful to the lungs, and its presence in certain “cleaner-air” devices remains questionable. UV light in small home appliances simply doesn’t have enough exposure time to effectively neutralize anything moving through the airflow, and it doesn’t remove particles — which are our main issue to begin with.

So what does actually work? A high-quality HEPA or HyperHEPA filter, proper airtight sealing, plenty of activated carbon, and clear, independently verified performance tests. No ozone, no gimmicks, no promises that sound like ads for magic potions.

It turns out that once we understand the basics, choosing an air purifier is no longer a gamble. We don’t need to be experts — just informed enough to distinguish real technology from marketing. That’s when we begin choosing devices that truly protect our health, not just our feeling that we’re doing something good.

Milena Maglovski

Energy passport – The id card of buildings

10.12.2025

energy-efficiency-154006_1280 (1) — Photo-illustration: Pixabay (OpenClipart-Vectors)

An energy passport is a certificate that outlines the energy performance of a building — an official document with a strictly defined format and content, issued by an authorized organization, and valid for a period of ten years. Its purpose is not to introduce another administrative requirement, but to provide owners and buyers with a clear and complete picture of how energy-efficient (or inefficient) a building is, depending on the category it falls into. Additionally, it provides insight into expected energy costs and recommends measures to reduce overall consumption.

The obligation to possess an energy passport stems from the EU Directive on the Energy Performance of Buildings (EPBD), which was first introduced in 2002. Serbia adopted it in 2005 upon joining the Energy Community. While specific systems vary from country to country, they share a common foundation — a scale of energy classes ranging from A to G, as well as mandatory categorization of buildings based on their energy consumption.

In Serbia, energy efficiency is expressed through energy classes — from A+, representing the highest level of energy performance, to G, assigned to buildings with poor characteristics and very high energy consumption. According to current regulations, new buildings must meet at least Class C standards. For reconstructions and renovations, it is required that the building’s energy performance improves by at least one class compared to its previous state.

According to the amendments to the Law on Planning and Construction from 2023, the energy passport, which had already been a requirement for obtaining a construction and occupancy permit for new buildings, is now also mandatory for all existing buildings. The amendments stipulate that, within three years, all public buildings must possess the certificate (deadline: August 2026), while business buildings are required to do so by 2028. Residential buildings have a ten-year deadline, which is practically until 2033. Once issued, the energy passport is valid for ten years. In the event of failure to meet this legal obligation within the prescribed period, according to current data, a fine ranging from 25,000 to 50,000 dinars is prescribed.

The issuance of the energy passport is based on an energy inspection of the building and project documentation. The energy inspection and certification process is carried out by a licensed engineer specializing in building energy efficiency, and the certificate is issued through the Central Register of Energy Passports (CREP) – an information system of the Ministry of Construction that maintains records of all issued documents and authorized organizations.

According to the Rulebook on the conditions, content, and method of issuing certificates on the energy performance of buildings, an energy passport for residential buildings usually consists of five pages. The first page contains basic information, including the owner’s name, location, and a photograph of the building, as well as the designation of the building’s energy class. The second page provides information on heating, cooling, and ventilation systems, the share of renewable energy sources, and data on the thermal envelope – walls, exterior doors, roof windows, and other categories. The third page presents, among other things, data on measured energy consumption, while the fourth contains recommendations for improvement, such as modernizing heating systems or enhancing insulation. The fifth page provides definitions of technical terms, such as: “Annual carbon dioxide emission (CO₂ [kg/a]) represents the mass of carbon dioxide emitted into the external environment during one year as a consequence of the building’s energy needs.”

According to the rulebook above, there are also exceptions. For example, an energy passport is not mandatory for buildings with a planned lifespan of up to two years, certain temporary structures, buildings that are not heated or are heated to a temperature of up to 12°C, buildings used for religious purposes, and other categories defined in the rulebook.

IN FOCUS:

Data from the Central Register of Energy Passports (CREP) – Current Situation in Serbia

According to the latest data provided by the Central Register of Energy Passports (CREP), as of September 30, 2025, a total of 21,693 energy passports have been issued in Serbia.

When it comes to energy classes, the most common is Class C, which also represents the legal minimum for all newly constructed buildings. According to CREP data, about 80.28 percent of all buildings fall into this energy class. They are followed by Class B buildings, which comprise approximately 7.8 percent, while buildings classified in Classes D, E, F, and G – representing lower energy performance – account for a total of around 8 percent. The remaining 3.91 percent of buildings belong to other categories.

In terms of territorial distribution, CREP reports that the number of issued energy passports largely follows the number of constructed and reconstructed buildings, as well as the population density and level of economic activity in a given area. In other words, the largest number of certificates is issued in major cities and more developed regions of Serbia, where construction activity is most intensive.

Energy Passports as a Tool Against Energy Poverty

Serbia has undertaken the obligation to align its energy sector with European standards and to implement essential reforms in the field of energy efficiency. It is precisely within this framework that two concepts intersect, which, although they may seem separate to some, are in fact deeply connected — the energy passport and energy poverty.

In March of this year, the Chamber of Commerce and Industry of Serbia published a document titled Guide to the Energy Passport and, with the support of the Heinrich Böll Foundation, organized a seminar on the topic. This document clearly outlines the relationship between the two concepts, as well as the importance of building certification in reducing energy consumption.

First and foremost, energy poverty refers to the inability of households to secure sufficient energy for basic needs such as heating, cooling, or lighting. It results from a combination of low income, high energy costs, and poor energy performance of buildings. In Serbia, according to data from the aforementioned guide, this problem affects around 200,000 households. An additional challenge comes from the large number of unregistered buildings — nearly two million — which, as they are not included in official records, cannot be covered by energy renovation programs or state subsidies, thereby further deepening social and energy inequality.

This is where the energy passport gains its broader social role and application — as a tool for overcoming energy poverty. Since it provides a transparent overview of a building’s energy performance and specific recommendations for improvement, households can, based on this information, identify where they are losing energy and money. Meanwhile, the state gains a foundation for designing targeted assistance programs, such as subsidies, furnace replacements, and energy renovation projects.

The most important piece of data in an energy passport is the energy efficiency parameter – the amount of heat required to heat a building during one year, expressed per square meter of heated surface. In Europe, according to the latest available data and the Guide, approximately 40 percent of the total energy produced is spent on heating and cooling buildings. In Serbia, this share reaches 47 percent, clearly indicating that the building sector is a key link in the energy transition.

Therefore, energy passports and systematic investments in improving energy efficiency represent the foundation of every serious policy aimed at reducing energy poverty and protecting the environment.

Prepared by: Milica Vučković

The story was published in Energy portal Magazine GREEN ARCHITECTURE