We claim that it is well worth investing in demand controlled indoor climate and it does not take very long before it pays off compared to constant flow ventilation.
The investment for a demand controlled system is often higher compared with a solution for constant flow ventilation. However, with the higher investment you get lower operating costs, a higher property value and in addition, you increase the productivity of the people who are in the building. In this blog post, we analyse how much more expensive demand controlled systems really are and the main factors that contribute to the repayment of the investment.
Productivity contributes to savings
One factor that is frequently overlooked when discussing investments and savings is the productivity of the people who are in the building. Indoor climate is strongly linked to human well-being and performance. With a demand controlled indoor climate, you can adjust the indoor climate on an individual level, which has a positive effect on performance. There is a rule known as 3-30-300, what it really says is a 10% increase in energy efficiency generates a specific saving per square meter, a corresponding 10% increase in staff productivity generates a saving a whole hundred times as great! Read more about IEQ here.
Reduction of operating costs
With demand controlled indoor climate, there are great opportunities to reduce operating costs in a number of ways. With the help of sensors, the indoor climate is measured and controlled according to the exact needs, which neither wastes the environment nor the economy.
Schools are a good example where demand controlled indoor climate can reduce operating costs significantly. One study shows that it is possible to save up to 80% of the energy for air handling and up to 40% of the energy for cooling and heating compared with constant flow ventilation. However, another study conducted in a school showed even greater saving possibilities for heating energy. In this school the rooms are only occupied at most for 30 minutes a day, or 110 hours a year, the rest of the time occupancy is considerably lower. When comparing heating energy consumption/year between constant flow ventilation and demand controlled indoor climate, the differences are clear:
• Constant flow ventilation consumes 35.07 MWh/year.
• Demand controlled indoor climate consumes 6.47 MWh, which means a reduction of more than 80%.
With a connected system, even service and supervision of operations can be performed remotely – which saves time and money. In addition, individual control of the indoor climate means a reduction in the number of error reports and costs associate with these by up to 25%.
A demand controlled indoor climate system usually involves a higher investment cost compared with constant flow ventilation. In a study that compared the installation price and energy consumption for different system types in a school with 16 rooms, the installation price for a demand controlled system was approximately 30% higher than for a constant flow system. In view of this, constant flow ventilation with its lower initial investment can be the right option for small-scale projects, where the demand is less advanced but where the investment cost is a critical factor. However, to attain an acceptable comfort level this solution risks being expensive in the long term due to a lack of energy efficiency and flexibility.
A demand controlled indoor climate system is energy efficient as the system delivers exactly as required. It ventilates, cools and heats neither too much – which costs energy – nor too little – which adversely affects comfort, but only as much as is needed.
If you choose a system with wireless communication, it will also be more flexible at the same time as the installation time is shortened appreciably by not having to route communication cables and by eliminating the risk of incorrect connections. Logistics throughout the building process are also simplified as products do not have to be preconfigured. One study shows that by using wireless climate products and sensors it’s possible to save 80-330 euros in installation costs per device compared with an equivalent demand controlled system that is not wireless.
Increased property value
There are many different aspects that influence a property’s value. The choice of ventilation and indoor climate systems affects several of these, such as low operating costs and individually adapted indoor climate (which contributes to higher productivity). High classification in different building certification programs and flexibility can also impact on the value of the property.
In recent years there has been a marked rise in the demand for environmental certification. Demand controlled indoor climate, which is both energy efficient and environmentally friendly, is a strong contributing factor to a high level of classification in different certification programs such as BREEAM Outstanding and LEED Platinum. Environmental certification often has a positive effect on both the value of the building and rent per square meter. Studies show that the value of a building can rise by up to 26% and the rent by 6% if the property is certified. Furthermore, 62% of property owners see a positive effect on the property value linked to high environmental certification.
Read more about environmental certifications here.
A wireless system contributes to flexible buildings that make it possible to utilise the premises more efficiently and simplify the process when renovating and repurposing. If any system requirements need to be adjusted, for instance, if walls are moved or activities in the premises change, the system can easily be altered without rebuilding being too expensive.
It’s difficult to put a general figure on how quickly an investment in demand controlled indoor climate pays for itself compared with constant flow ventilation, as it varies greatly from project to project. The previously mentioned study in a school shows that the investment in a demand controlled indoor climate system compared with constant flow ventilation pays off in terms of energy savings after about 4 years. One reason is the low degree of occupancy which brings about the possibility to save energy. What can generally be said about demand controlled systems is that you get low operating costs, a comfortable individually adapted indoor climate, increased performance and the possibility to environmentally certify the building according to the highest levels. Choosing a wireless system also makes it possible to reduce the installation costs considerably compared to a wired option. In summary it’s often worth the extra investment in demand control indoor climate compared with constant flow ventilation.
Wireless demand controlled ventilation – a cost-benefit analysis and comparison of installation
costs, Jens Kunter Bergersen, 23/05/2019
Making school buildings more energy efficient through demand controlled ventilation.
Evelina Lann & Julia Lysén, 2011
Juha Pasila, Demand controlled ventilation in school buildings, 2013, Seinajoki university of applied sciences.