Signs Your Kitchen Extract System Is Underperforming

A reliable kitchen extract system is one of the most important parts of any commercial kitchen. It keeps the air clean, removes heat and grease, and helps ensure your space stays safe and compliant with UK regulations.  

When it starts to underperform, the effects can quickly spread across your entire operation. 

At Sigma Engineering, we work directly with commercial kitchens to design, manufacture and install high-performing extraction and ventilation systems.

From busy restaurants to large catering environments, we’ve seen how small issues can turn into serious problems when they’re ignored. Knowing what to look out for can help you act early and avoid disruptions. 

Below are some of the most common signs that your kitchen extract system isn’t performing as it should. 

Lingering Odours That Don’t Clear 

In a well-functioning commercial kitchen ventilation system, cooking smells should be extracted quickly and efficiently. If odours are hanging around long after service or spreading into dining areas, it’s a clear sign something isn’t right. 

This usually points to poor airflow or a blockage within the system. Grease building-up inside ductwork or clogged filters can restrict extraction, preventing contaminated air from being removed properly. Over time, this doesn’t just affect the comfort of your staff. It can also impact the experiences of your customers. 

At Sigma Engineering, we carry out airflow testing and system inspections to pinpoint exactly where performance is dropping and restore proper extraction. 

Rising Heat Levels in the Kitchen 

Kitchens naturally get hot, but a properly designed extraction system should remove a large portion of that heat. If your kitchen is becoming noticeably hotter, especially during peak hours, your system may be struggling. 

Excess heat is often caused by insufficient extraction rates or poorly balanced airflow. This can make the working environment uncomfortable and even unsafe for staff, particularly during long shifts. 

We regularly help clients optimise their kitchen ventilation systems to improve temperature control. By adjusting airflow and upgrading components where needed, we make sure heat is effectively removed from the space. 

A Visible Build-Up Grease  

Grease is an unavoidable by-product of cooking, but it should be captured and extracted through your system. If you’re noticing grease collecting on walls, ceilings or equipment, it’s a warning sign that your system is underperforming. 

This often happens when filters are no longer effective or when ductwork hasn’t been properly cleaned. Over time, grease accumulates inside the system, reducing efficiency and increasing the risk of fire. 

At Sigma Engineering, we provide professional ductwork cleaning and maintenance services in line with TR19 guidelines. Keeping your system clean not only improves performance but also helps you stay compliant with safety regulations. 

Smoke and Steam Not Being Captured 

If smoke or steam is escaping into the kitchen instead of being drawn into the canopy, your extraction system is likely not operating at the correct capacity. 

This could be due to poor system design, worn-out components, or airflow imbalance. In some cases, the system may have been suitable when first installed but no longer meets the demands of a busier kitchen. 

We often work with businesses to upgrade or redesign their systems so they match current usage. Ensuring proper capture and containment is key to maintaining air quality and preventing wider ventilation issues. 

Unusual Noises or Vibrations 

A commercial kitchen extraction system should run consistently in the background without drawing attention to itself. If you start hearing unusual noises such as rattling, humming or vibrations, it’s often a sign of mechanical issues. 

Fan motors may be wearing out, components could be loose, or airflow may be unbalanced. Left unresolved, these issues can lead to system failure and unexpected downtime. 

Preventative maintenance is one of the most effective ways to avoid costly repairs. 

Increasing Energy Costs 

An inefficient extraction system doesn’t just affect performance. It can also have a noticeable impact on your energy bills. 

When systems are blocked or struggling, fans and motors have to work harder to achieve the same results. This increases energy consumption and puts additional strain on the system. With energy bills soaring in the UK, it’s vital that your system is operating well. 

We help clients improve energy efficiency by optimising system performance, replacing outdated components, and ensuring airflow is properly balanced. A well-maintained system will always operate more efficiently and cost-effectively. 

Signs of Non-Compliance 

In the UK, commercial kitchen ventilation systems must meet strict safety and hygiene standards. If your extract system is underperforming, there’s a risk you may fall short of these requirements. 

Issues such as grease build-up, poor airflow, or lack of maintenance can all lead to compliance failures. This can result in failed inspections, enforcement action, or even temporary closure in serious cases. 

At Sigma Engineering, we design and install systems that meet current regulations and industry standards. We also support businesses with inspections and documentation, giving you confidence that your kitchen remains compliant. 

Why Acting Early Matters 

It’s easy to overlook small changes in your extraction system, especially in a busy kitchen environment. But these early warning signs are often the first indication of a larger issue developing. 

Ignoring them can lead to: 

• Reduced air quality 

• Increased risk of fires 

• Higher operating costs 

• Unexpected system breakdowns 

By addressing problems early, you can extend the lifespan of your system and avoid disruption to your business. 

How We Support Commercial Kitchens 

At Sigma Engineering, we take a practical, hands-on approach to kitchen ventilation. We work closely with our clients to understand how their kitchens operate and deliver solutions that actually work in real-world conditions.

Our services cover every stage of your system’s lifecycle. We design and install new extraction systems tailored to your space, upgrade existing systems to improve performance, and carry out regular maintenance to keep everything running smoothly. 

We also specialise in airflow testing, and system optimisation. Whether you’re dealing with poor airflow, rising energy costs, or compliance concerns, we can identify the root cause and put it right.