Common Mechanical Engineering Mistakes in Commercial Projects (and How to Avoid Them)

At the heart of any structurally complex modern skyrise is an impressive array of unseen mechanical engineering. For new commercial projects, it is simply a non-negotiable inclusion, holding up vital systems like internal HVAC, building automation, and smoke control for emergencies.

Unfortunately, due to the complexity of this field, many common mistakes a novice mechanical engineering team might fall prey to. Even further, a team without a mechanical engineer to consult on the installation of these systems is likely to run into at least one of the issues we’ve highlighted in this list.

To help you avoid these mistakes, we are going to unpack four of the most common mechanical engineering mistakes from an engineering perspective. With these mistakes clearly in the open, we hope this underscores the importance of securing an engineering consultant during your build, or of working carefully to avoid these mistakes throughout the construction phase.

Mistake #1: Undersizing or oversizing your HVAC systems.

Unfortunately, one of the most common mechanical engineering mistakes we see in many new commercial developments popping up around Auckland is a simple detail: a poorly sized HVAC system. This usually involves an inappropriate load calculation for the building’s heating, ventilation, or air conditioning.

This is a pretty delicate system. If your development has an undersized system, the building will rarely reach a comfortable temperature. On the other hand, oversizing a system is just as problematic. An oversized HVAC unit will essentially “short-cycle”, turning on and off rapidly.

In this way, your air will never truly be dehumidified, which can be a massive problem in Auckland’s humid climate. Not only that, but it shortens the lifespan of your compressors and spikes your energy consumption.

The goal is to reach the “Goldilocks” zone, where the building’s HVAC system is appropriately sized for the building’s size and occupancy. This usually requires precise thermal modelling that accounts for factors such as window orientation, insulation R-values, and the expected number of computers generating heat in an office space.

Even with a correctly sized system, poor air balancing can undermine performance. Excessive air velocities caused by incorrect diffuser selection or unbalanced airflow can lead to noise issues such as whistling through doors, grilles, and diffusers. Proper commissioning and air balancing are essential to ensure the system operates quietly, efficiently, and as intended.

In short, it’s no wonder that this is one of the most common mechanical engineering mistakes out there, but it’s also one of the most vital to avoid.

Mistake #2: Neglecting maintenance access in the design phase.

We see this one all the time. In the rush to maximise leasable floor space, many commercial developers prioritise squeezing mechanical systems into tiny, inaccessible plant rooms or ceiling voids. This is high on the list of mechanical engineering mistakes because it creates an absolute nightmare for the building’s lifecycle.

Maintenance should be quick and easy, especially if a major issue crops up. If a technician has to dismantle an entire wall or structural element just to swap out a filter or inspect a damper, the owner’s maintenance costs will skyrocket.

From an engineering aspect, one of the core principles we will always advocate for is “serviceability”. Essentially, if it’s hard to reach, it won’t be maintained. If it isn’t maintained, it will eventually fail. And no one wants that.

Mistake #3: Poor or Inadequate Zoning.

Inadequate HVAC zoning is a frequent and costly mistake in commercial projects, particularly in modern open-plan office environments. While open-plan layouts may appear uniform, they often contain areas with significantly different thermal demands that cannot be effectively served by a single zone.

Perimeter zones, especially those with large areas of glazing, are subject to increased heat gain in summer and heat loss in winter due to solar exposure, wind, and external temperature fluctuations. These areas experience much higher and more variable loads than internal zones, which are typically influenced by internal gains such as occupants, lighting, and office equipment. When perimeter and interior spaces are grouped into the same HVAC zone, the system is forced to compromise, leading to uneven temperatures and ongoing comfort complaints.

Poor zoning also drives inefficiency. Systems often over-condition internal spaces to meet perimeter conditions, resulting in wasted energy, excessive fan operation, and increased wear on HVAC equipment. 

Effective zoning separates perimeter and internal areas and accounts for differing occupancy patterns and heat loads. When designed correctly, zoning allows HVAC systems to respond accurately to real building conditions, improving comfort, reducing energy consumption, and extending equipment lifespan. Overlooking zoning during the design stage is a common mistake that can significantly impact both operational performance and occupant satisfaction.

Mistake #4: Inadequate acoustic and vibration control.

Any modern skyscraper is a masterpiece of glass and steel, both of which just so happen to be very conductive materials. Though the modern look is beautiful, it can also create constant vibrations from interactions between mechanical systems and the materials surrounding them.

One of the most common mechanical engineering mistakes is constructing these large developments from sleek materials without the acoustic and vibration control to back them up.

Luckily, solving vibration issues in the design phase is just a matter of making the right investment. However, if you discover the issue once the building is occupied, it often requires much more expensive structural retrofitting.

With these four mechanical engineering mistakes covered, it’s clear that bringing an engineering consultant into your development in the design phase is vital to avoid costly issues down the line. We ensure that the alarm sounds when pulled, that the building is clean and quiet, that all occupants are comfortable, and that your investment pays off.

We are Agile Engineering, your trusted team of mechanical engineering consultants.

With decades of cumulative mechanical engineering experience on our team, we are proud to provide commercial developers across Auckland with easy access to expert consultants at any stage of their build. Agile Engineering is the place to go when you need complete assurance that your development will reach its finishing stages.

Whether you’re scoping out the discovery for your build now or require a consultant prior to final inspections, reach out to our team for an experienced mechanical engineering lens on your development today.