Climate control in buildings should be taken much more seriously

It is mandatory to perform an energy performance calculation for new or renovated homes or buildings such as sports halls, swimming pools and schools. In other words, the energy value of a building must be determined and an appropriate energy label assigned. This calculation is based on NZEB criteria: Nearly Zero Energy Buildings. But for Jaco Mooijaart, Head of the Electrical and Mechanical Engineering department at Iv-Bouw, the mandatory calculation takes too few factors into account, which results in an ‘on paper’ reality in which some of the climate targets can only be met in theory.

NZEB criteria
As of the 1st of January 2021, calculations based on these NZEB criteria are mandatory for permit applications. As a specialist in utility construction, Iv-Bouw is often involved in such calculations, for example, for schools, public swimming pools and multifunctional sports halls. Until 2021, calculations were based on a so-called Energy Performance Certificate (EPC). The new NZEB criteria are assessed in three parts: the annual energy demand (number of kilowatt hours per year), the fossil energy consumption (heating, cooling, ventilation, etcetera) and the percentage of renewable energy.

I think it is our responsibility as consultants to remain very critical in our observations.

‘On paper’ reality
Iv-Bouw is legally required to apply these calculations but observes an overly simplistic representation of reality in practice. For example, the annual averages of a building are taken from the NZEB criteria without sufficient consideration being given to the peak capacity, the type of use or, for instance, the loss of efficiency due to climate control through air ventilation. A ventilation system occupies much more space and has higher transport losses than a waterborne climate system. This is rarely reflected in the results of EP calculations for clients. A cheaper method of climate control using an air conditioning system is often preferred. Yet, this option consumes much more energy than the figures suggest and is, therefore, more expensive in operation.

“Schools and sports halls often opt for an all-air system, whereby the indoor climate is controlled solely with air. While in principle, ventilation is intended to prevent people from exposure to high levels of CO2 in a building”, explains Jaco Mooijaart. “But these types of spaces are usually in constant use. In our opinion, you can control the indoor climate perfectly well with water, plus it is more advantageous from an energy point of view. It may be a slightly higher initial cost because this option requires more systems, but it will ultimately pay off.”

Much is still to be achieved, as well as raising awareness among clients.

The fact that this is not clearly reflected anywhere in the calculations for a permit application concerns Jaco because important decisions are being made based on incomplete information. “This means that, in theory, (nearly) energy-neutral buildings are being built, but in reality, this may not be the case. I think it is our responsibility as consultants to remain very critical in our observations. It is good that there is a national standard for applying for a permit, but it must reflect the whole story. After all, such criteria were created to prevent energy-guzzling buildings from being built. Which now somewhat defeats that purpose.”

Customise per building
As far as Iv-Bouw is concerned, the uniformity of the calculations also does not accurately reflect customisation. Average consumption for an average building is assumed. But each building is different. “This model can also be applied to a swimming pool, also a building with a sports function, but I don’t think I need to explain to anyone that heating a swimming pool in an energy-neutral way is almost utopian. A swimming pool consumes much more energy than a normal sports hall, and yet the results of an EP calculation are the same. So something has to be done, beginning with recognising the problem. Our market runs on this, but the coverage is not sufficient.”

These NZEB criteria will still apply for the time being. But fortunately, Iv-Bouw can lean on its many years of experience and highly specialised knowledge in utility construction and consulting on (sustainable) installations. Moreover, Iv-Bouw can use its expertise to substantiate advice to school boards or municipalities during the preparation phase of new construction or renovation plans. Jaco: “Much is still to be achieved in this area, as well as raising awareness among clients. It’s a shame our advice is not derived from these criteria, but clients can rely on our expertise.”

Examining the surrounding environment closely is interesting and useful. How can it be utilised?

New buildings achieve more
Making public buildings more sustainable is a major challenge and depends on numerous other factors. But, as stated above, new buildings can achieve a higher result. And that’s needed. According to the Paris Climate Agreement, global CO2 emissions must be reduced by at least 95 percent by 2050 to ensure the Earth does not warm by more than 1.5 degrees Celsius.

The more energy a building consumes for indoor climate control (heating, cooling and ventilation), the harder it will be to achieve this target by 2050. Nevertheless, Jaco believes Iv-Bouw can play a vital role in advising property owners and providing well-founded advice and recommendations that extend far beyond the NZEB criteria. “You have to include variables if you want to tell a fair story, for instance”, he continues. “If you’re showing that a swimming pool is almost energy neutral ‘on paper’, but it’s not, you could include other suggestions or proposals.”

Heat from outside
Think bigger is the opinion of Iv-Bouw. And above all: think outside the box. This also applies, for example, to municipalities that are responsible for school buildings, sports halls and libraries for the community. These types of facilities are, of course, bound to a place or region. “But examining the surrounding environment closely is still interesting and useful. How can it be utilised? For example, the possibility of using residual heat from a neighbouring (production) building or cooling a building with surface water. Of course, not every municipality will have this luxury, but we are increasingly seeing this happening.”