Insulation of industrial halls has become an increasingly common topic in recent years. The reason is simple – it significantly reduces heating or cooling costs, contributes to environmental protection, and increases worker comfort. But how much money can you actually save? Let’s calculate it together.
Every building loses heat through its envelope structures, which include roofs, walls, floors, and windows. Heat loss is defined as the amount of heat that passes through a certain area over a certain period of time and under certain temperature conditions. The rate of this heat loss is measured in units of W/m2*K and is referred to as the thermal transmittance (U-value). The lower the U-value of a material, the less heat the material lets through and the more effective it is in terms of insulation.
Standard PIR sandwich panels with a thickness of 100 mm have a U-value of around 0.22 W/m2*K, and panels with a thickness of 120 mm have a U-value of about 0.18 W/m2*K. Recently, there have also been requirements for panels with a thickness of 150 mm and a U-value of 0.15 W/m2*K.
Another crucial factor is the area of the panels used in the hall. For simplicity, we can calculate with an area A = 100 m2.
To get the result, we still need the time value (t) and the temperature difference between the outside and inside (ΔT). Every building may face a different situation, so we can assume a half-year heating season. In this example, the temperature difference is set at 20 degrees.
If you want to calculate your own savings, the following formula is used:
QkWH = U · A · △T · [t(hours)/1000]
When using standard 100 mm panels, the heat loss during the heating season is approximately 1900.8 kWh. For better insulated panels with a U-value of 0.18 W/m2K, the heat loss is reduced to 1555.2 kWh. The heat loss for panels with a thickness of 150 mm is 1296 kWh. If the price per 1 kWh of energy is 4 CZK, the financial savings amount to approximately 1382 CZK between 100 and 120 mm sandwich panels and 2419 CZK between 100 and 150 mm panels.
So the discussion is not about whether to insulate or not. Non-insulated halls still have lower usability, primarily for storing temperature-sensitive materials. Currently, the question is how much to insulate. A saving of 1382 CZK or 2419 CZK per heating season may not seem significant, but let’s look at an example from one of our quoted halls.
The hall Promo 756 is clad with 629 m2 of panels, and the design includes 120 mm thick panels with a cladding price of 906,000 CZK.
The price of the cladding with 100 mm panels is 880,000 CZK, which is 26,000 CZK lower than with 120 mm panels. However, if we reduced the panel thickness, the annual heat loss would increase heating costs by 8,700 CZK. Over 25 years, this increased cost would amount to 217,500 CZK, which would significantly exceed the savings on the initial investment. The return on this decision would be inefficient, because in less than 3 years the additional heating costs would surpass the initial savings.
The price of the cladding with 150 mm panels is 1,017,000 CZK, which is 111,000 CZK more than with 120 mm panels. However, increasing the panel thickness brings an annual heating cost saving of 6,500 CZK. Over 25 years, this saving would amount to 162,500 CZK, which means that the higher initial investment would pay off in approximately 17 years.
In conclusion, 150 mm thick sandwich panels are the best in terms of panel lifespan, but not everyone is willing to wait 17 years for a return on investment, and in that case, the 120 mm option is more suitable. Everyone can use the mentioned formula to check whether investing in insulation is worthwhile for them.
