Do you know how much energy you are losing through your doors?

Frico Fact Sheet

As inviting as open doors and entrances may be, they are unsuspecting culprits leading to significant and costly energy losses and an overall poor indoor environment. Here’s why.

The ever-evolving topic of energy

Saving energy has always been important, especially with increasing energy prices. According to Eurostat in the first half of 2022, aver age electricity prices in the European Union (EU) increased sharply compared with the same period in 2021, from 22.00 EUR per 100 kWh to 25.30 EUR per 100 kWh.

Average gas prices also increased compared with the same period in 2021 from 6.4 EUR per 100 kWh to 8.60 EUR per 100 kWh in the first half of 2022. More recently, wholesale prices for electricity and gas have increased substantially across the EU. The trend is expected to continue, according to several news reports. The growing emphasis on energy savings can also be linked to the increasing awareness of the need to pursue sustainable operations in the face of the alarming effects of climate change.


Ensuring energy savings is critical to saving money and preserving operational costs, a concern for commercial businesses such as malls, restaurants, industrial facilities, food retailers and the small utility sector. It is also necessary to ensure the company’s sustainability amid ever-increasing energy prices and stringent minimum energy consumption requirements.

Stores, shops and facilities are working to be more vigilant when closing their doors. While such good practice should be encouraged as a standard, even if the doors remain shut most of the time, fulfilling its purpose of letting people in and out of the space will already result in significant losses of expensively heated or cooled air. The purpose of an entrance door is to let people and goods in and out. Access doors will, therefore, always be opened, inevitably leading to energy loss.

Why are doors and openings leading to energy losses?

The reason for this energy loss is because of air infiltrations, also known as airleakages, often caused by the unintentional or accidental introduction of outsideair into a building through cracks in the building envelope or entrance doors. The amount of air that flows out through an open door depends on differences in pressure between the indoor and outdoor air, which depends on three factors:

Simply put, if the conditions on one side of the door differ in any way from those on the other side, then there will be a draught from the door opening. Air flows out through an open door to equalise the differences in pressure and temperature. In heated premises, hot air flows out and cold air flows in. Wind blowing towards the door also affects the airflow.

A study from AMCA showed that air infiltrations can be as high as 18% of the total heat loss for commercial buildings alone. The study further highlighted that filtrations through door openings become quite significant when the doors are frequently used, such as in restaurants, retail stores, supermarkets, offices and hospitals.

Given this fact, applying measures that can effectively and efficiently save energy at entrance doors is essential. Air curtains create an invisible barrier at openings and doors which separates different temperature zones without limiting access for people and vehicles. Losses of heated or cooled air through door openings are thus significantly reduced with correctly installed air curtains.

In the second part of this series, we will discuss why using ai r curtains is critical to conserving energy and protecting the working environment.