For almost everything we do, we use buildings. We eat, sleep, work, train, shop, and meet friends, all under a roof.
Buildings have evolved from simple caves for sheltering, to high-tech spaces that can give us everything we wish for and more. Because we spend so much of our time inside buildings, we require a lot of them. As a result, buildings represent 40 percent of the total energy consumption in the European Union.
This means that the energy use of our buildings has a significant impact on the total energy consumption. This matters, because the amount of greenhouse gases, such as CO2, that end up in our atmosphere is directly related to our energy use. A surplus of these gases results in global climate changes, as we are experiencing now. We cannot slow down climate change without lowering the energy performance of our buildings.
Older buildings drain energy
Most of the energy in buildings is used for heating, especially in Central and Northern Europe. This energy disappears through the walls, roof, floor, and windows. Because of this, we see that new buildings have thicker walls and smaller windows to keep heat losses to a minimum. However, around 80 percent of the buildings in Europe were built before 1990 and are considered as older buildings. These buildings have only a thin layer of insulation and large windows with air leaks around them. They are large energy drains.
The key to solving this is upgrading these buildings to become more energy efficient. This means that the amount of energy used for something, like heating a house, is lowered while still having the same result (e.g., the same room temperature). As a result, the energy use will be lowered as well as the amount of produced greenhouse gases.
The most popular approach towards energy efficient buildings is adding insulation to walls, roof, and floors, and blocking air leaks in the building. This will lower the energy consumption of the building, resulting in a lower energy bill, and improve the indoor comfort by removing cold floors and draft. This sounds simpler than it is. Investment costs of upgrading can be high, and the building owner might not have the time or the right knowledge to upgrade the building. Should the minimal requirements be chosen, or a more expensive option with better performance? To make it even harder, upgrading a building to today’s standards is not enough. Buildings should be future-proof so that they can easily adapt if the requirements change.
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Different solutions for each building
A relatively cheap and easy solution for saving energy is installing a control system that can monitor and control the heating, ventilation, and lighting; also called building automation. The smart system can even be extended to include smaller appliances, such as coffee machines. However, it can be challenging to install a system like this in existing buildings. For example, if no central heating and ventilation system exists in the building, the investment costs can be high. Even more importantly, the energy savings compared to adding insulation and closing air leaks are low. Those necessary upgrades should be completed first.
Upgrading buildings can be a complicated process. Even though there are many acceptable solutions available for giving a building higher energy efficiency, it can be challenging to choose the right solutions. The success of a solution is based on the type of building, the benefits, and the balance of costs and savings. Therefore it is essential that we find out what combination of solutions works best for specific buildings. The ENERSENSE group at NTNU looks into this with a team of motivated researchers from different fields. We work for a better world!