Frequently asked questions about our company and our products
What sets your company apart from other ventilation system suppliers?
Our company offers professional consulting, fast delivery, competitive prices, and reliable after-sales support. Our team has over 20 years of combined experience in the ventilation industry, and our expertise is further supported by our external partners – installers who ensure quick response times, professional installation, and proximity to your home for after-sales services.
What types of ventilation systems do you offer?
We offer local heat recovery units, central ventilation systems, fans, and inspection doors.
How can I place an order, and do you offer cash on delivery?
Orders can be placed through our website, by phone, or via email. In our online store, payment is made via pro forma invoice, and the order is confirmed once payment is received. We also offer cash on delivery (Slovenia only), please let us know by email or phone if you prefer this option. For cash on delivery, an additional fee from Pošta Slovenije applies (€1.20 + VAT). For deliveries to other countries, you can generate an online order, but don't pay it, send us the number, delivery details in email to info@prezracevalni-sistemi.com. We will prepare you updated proforma invoice with calculated shipping costs depending on our logistic partner prices, updated VAT value and information about stock and delivery dates.
Do you offer discounts and promotions?
Yes, we regularly organize seasonal promotions where customers can save on ventilation systems, heat recovery units, and other products.
How can I collaborate as a ventilation system installer, distributor or re-seller?
We’re always open to new partnerships — you can apply via the contact form on our website or contact us by email or phone - we speak english, german, spanish, croatian and serbian.
What does your consulting service include?
We help you choose the right ventilation system, calculate the required capacity, and recommend the optimal solution. Once the offer is confirmed, we also prepare an indicative layout of the ventilation system (or a combination of systems), which serves as the basis for installation.
How quickly will I receive my order?
Items in stock are shipped the same or the next business day. For products available through our suppliers, we ensure the fastest possible delivery. It’s important to understand that operating costs are increasing daily, and storing slow-moving products adds extra costs, which suppliers eventually pass on to customers. That’s why our approach is different: we only keep regularly sold products in our warehouse, while other items are stored with our suppliers. If you order an item that’s out of stock, we’ll immediately inform you and provide an estimated delivery date. If that doesn’t suit you, we’ll cancel your order and refund your payment no later than the next business day.
How does your online webstore work?
Our online store offers ventilation systems, installation materials, and complementary installation products. One of our best-selling products is inspection doors. Not all items are in our physical stock — as stated on our homepage — but they are available at our suppliers. Since operating costs continue to rise, we only store products that sell regularly to avoid unnecessary warehouse costs, which would otherwise raise prices for customers. If you order an item that’s out of stock, you’ll be promptly informed and notified of the expected delivery date. If that date doesn’t suit you, your order will be canceled, and your payment refunded within one business day.
Do you also provide installation services for ventilation systems?
At Evekum d.o.o., the company operating www.prezracevalni-sistemi.com we primarily focus on consulting, sales, and technical support. However, because comprehensive service is important to our customers, we also offer system installation in cooperation with experienced installers across Slovenia, ensuring fast and high-quality installation in your area.
How can I request a quote for a ventilation system?
You can submit an inquiry via our website form or by email. We’ll then contact you with a preliminary offer and possible solutions. To avoid calling you at inconvenient times (at checkout, in a meeting, or carrying groceries), please provide as much information as possible when submitting your inquiry — room sizes, number of floors, wall and ceiling materials, wall thickness, or ideally, attach a floor plan or other documentation.
Are your systems suitable for new builds and renovations?
Yes, our decentralized heat recovery units and central ventilation systems are suitable for both renovations and new constructions.
What is a heat recovery unit and how does it work?
A heat recovery unit is a ventilation device that extracts heat from the outgoing air and transfers it to the incoming fresh air. Compared to conventional ventilation systems, it significantly reduces heat loss, which can otherwise lead to high heating costs during winter.
What does air heat recovery mean?
Heat recovery is the process of transferring heat from the exhaust air to the incoming air, reducing energy losses.
Why choose a ventilation system with heat recovery?
It provides fresh air, reduces indoor humidity, and lowers heating costs during the winter months, which would otherwise be higher with regular window ventilation.
What’s the difference between a decentralized heat recovery unit and a central ventilation system?
A decentralized unit ventilates a single room, while a central system ventilates the entire house or apartment. It’s also possible to effectively ventilate a whole home with local systems by placing them strategically and connecting their operation.
What is ventilation with heat recovery?
It’s controlled ventilation where the air is filtered and heat-treated without energy loss.
What are the main advantages of ventilation systems?
Fresh air, reduced humidity, prevention of mold, lower energy losses, and improved living comfort.
How efficient is heat recovery?
Modern systems can achieve up to 95% heat recovery efficiency. The efficiency depends on airflow volume per second — higher airflow means slightly lower heat recovery. When designing your ventilation system, it’s important to calculate the air volume correctly so that your system operates at the lowest possible speed — ensuring high heat efficiency, low power consumption, and minimal noise.
What are fans, and where are they used?
Fans are used to extract or supply air in bathrooms, toilets, kitchens, and other rooms. Most fans operate in one direction — either extracting or supplying air — although some bidirectional fans exist (which halve the airflow). Fans don’t include heat recovery, so they don’t return heat to the incoming air.
What are inspection doors, and why are they important?
Inspection doors are installed on walls or ceilings to provide easy access to ventilation ducts and allow system maintenance. They come in plastic or metal versions in various colors, as well as special types for ceramic or drywall finishes, allowing a seamless appearance with the surrounding wall or ceiling.
Are ventilation systems energy-efficient?
Yes, with systematic ventilation and heat recovery, they reduce heating energy consumption. This doesn’t mean they directly lower your heating bill, but they recover heat from the exhaust air and transfer it to incoming fresh air. Without heat recovery, opening windows for ventilation introduces cold air, increasing heating costs. Since a heat recovery unit transfers most of the heat to the incoming air, the additional heating required is significantly lower compared to traditional window ventilation.
How do ventilation systems affect health?
They remove moisture, dust, pollen, CO₂, and allergens — ensuring a healthy indoor environment.
How does ventilation prevent mold growth?
By continuously removing humidity and maintaining air circulation, ventilation reduces conditions that promote mold growth. Optimal indoor humidity is between 40–60%. If humidity remains above 80% for longer periods, mold can develop. Regular ventilation prevents moisture buildup on walls. However, if humidity is caused by leaks or poor insulation, the source must be fixed before addressing mold prevention.
What does systematic ventilation mean?
It’s continuous, automatic, and controlled ventilation of all rooms. This is only possible with a ventilation system, as opening windows and doors regularly (for 5 minutes every 1.5 hours) is unrealistic, especially at night.
How much does heat recovery cost?
A local heat recovery unit costs between €300 and €800, while a central system starts from €3,500, depending on the building and installation requirements. Installation costs can be reduced significantly in new constructions if planned early — avoiding additional drilling or wall chasing later in the process.
Is investing in heat recovery worth it?
Yes, because it reduces heating and cooling costs, and the investment pays off within a few years.
Are ventilation systems suitable for people with allergies?
Yes, filters in heat recovery units effectively trap pollen and other allergens, especially filters rated F7, F8, or F9. Standard filters in local units are typically G4, which only trap coarse particles. It’s possible to upgrade to an F7 or F8 filter in most local units if wall thickness allows. Installing these filters requires no additional work — they simply slide into the existing duct — but note that they reduce airflow to some extent.
How much heat can a heat recovery unit retain?
High-quality systems can retain up to 95% of the heat from exhaust air.
What does a ventilation system include in practice?
It’s a combination of a heat recovery unit, ducts, fans, and filters that work together to ensure fresh, clean air.
Why is a ventilation system better than opening windows?
Because it prevents heat loss, reduces dust and noise, and continuously provides clean air. Effective ventilation requires a full air exchange every 1.5 hours — meaning windows would need to be fully opened for at least 5 minutes every 90 minutes, which isn’t practical, especially at night.
How often should a ventilation system be serviced?
Filters should be cleaned every 3–6 months and replaced every 1–2 years, depending on air pollution levels. Ventilation ducts should be cleaned every 8–10 years.
