It's one of the most common questions we get asked before a combi oven installation: do I need extraction? The honest answer is: it depends — but in most professional kitchen environments, the answer is yes. And getting it wrong can cost you far more than the ventilation itself.
This guide covers everything you need to know about combi oven ventilation: the regulations behind it, when extraction is genuinely optional, and what your options look like across the brands we work with most — RATIONAL, Electrolux, Convotherm, Lincat and more.
*If you're buying a refurbished combi oven through CaterCombi and have questions about ventilation for your specific installation, please get in touch. We work with kitchens across a wide range of environments and can help you understand what's required before the oven arrives on site.
Combi Ovens Produce Emissions That Need Managing
A combi oven combines steam, convected heat, and often high-temperature roasting. During a typical day's service, it will expel significant quantities of steam, heat, cooking odours, and — depending on what you're cooking — grease-laden vapour. Even an electric unit running a gentle steam cycle will push moisture into your kitchen environment continuously.
Left unmanaged, this creates several problems:
- Excess humidity affecting staff comfort and food storage conditions
- Grease and condensation accumulating on surfaces, creating hygiene and fire risks
- Poor air quality and heat build-up for kitchen staff
- Potential damage to surrounding cabinetry, walls, and adjacent equipment
Ventilation isn't just about compliance — it protects the kitchen environment and extends the working life of everything in it.
When Might Extraction Not Be Required?
There are scenarios where a full extraction canopy to the outside isn't strictly necessary, though they come with caveats.
Light-use electric ovens in naturally ventilated spaces. A small countertop electric combi running occasional reheating cycles in a well-ventilated kitchen may not generate enough emissions to require a dedicated extraction system. However, "well ventilated" has a specific meaning under DW/172 — it's not simply a matter of opening a window.
Front-of-house or counter-service environments. Some operators position compact combi ovens in customer-facing areas — hotel breakfast stations, deli counters, quick-service settings. Here, extraction to the outside may not be structurally possible, and the oven may be used for lower-emission processes like reheating pastries or baking rolls. In these situations, an inline condensing hood (see below) may be sufficient, provided the cooking type and volume justify it.
Cooking processes with minimal grease and odour. Steam-only cycles, low-temperature regeneration, and bakery processes generate far less in the way of grease-laden vapour than, say, high-temperature protein roasting. The type of cooking matters as much as the oven itself.
Even in these cases, we'd always recommend a conversation with a ventilation specialist and, where required, your local environmental health officer before proceeding without extraction. Getting it wrong after installation is expensive.
RATIONAL: UltraVent and UltraVent Plus
RATIONAL® has a well-thought-out approach to ventilation. Its combi ovens are designed to work with its own recirculating condensation hoods, which sit directly on top of the oven and deal with steam and cooking vapour at the source. The hood captures the steam, condenses the moisture, filters the air and returns clean, dry air to the kitchen. It does all of this without external ducting, so you can run a RATIONAL® combi in places where a conventional extraction system would be impractical.
How it works
- Steam capture. The hood captures steam from the oven's top exhaust vent and the bursts released each time the door opens.
- Condensation. Internal condensation plates cool the moist air, turning the steam into water. The water drains away through the oven's existing drain connection, so you don't need a separate drain line. This keeps humidity down and stops steam clouds building up in the kitchen.
- Filtration. The air is filtered before it leaves the hood. How much filtering it gets depends on the model (see below).
- Recirculation. Clean, dry air goes back into the kitchen. No ducting or external exhaust connection is needed.
- Automatic operation. The hood is wired into the oven's sensors. Fan speed adjusts automatically to the cooking mode and boosts whenever the door is opened.
UltraVent
The UltraVent is RATIONAL®'s core condensation hood. It handles steam and light vapours, which makes it the right choice for kitchens that mainly use steam and combination cooking. The job here is to stop steam escaping into the kitchen rather than to deal with smoke. Heavy grilling, roasting or other smoke-producing cooking can go beyond what it's designed to handle.
UltraVent Plus
The UltraVent Plus uses the same condensation technology and the same drain connection. It adds extra filtration layers of grease filter, prefilter and HEPA main filter, which remove the smoke and grease produced when grilling, roasting and frying. This lets you use the oven's full range of cooking modes in places where smoke and odour would otherwise be a problem. (Older UltraVent Plus models use an activated carbon filter instead.)
Where they make sense
Because neither hood needs ductwork, both open up installations a conventional canopy can't easily reach:
• basement kitchens
• listed buildings where external ducting would need planning consent
• rented or leased premises
• open kitchens and front-of-house counters
• temporary kitchens
• anywhere structural constraints make ducting impractical
Both can also be retrofitted to existing installations. Current iCombi ovens are compatible, and SelfCookingCenter and CombiMaster Plus models need an adapter kit. The UltraVent Plus is the stronger fit for most of these settings, especially customer-facing ones.
Worth knowing
Both hoods manage steam and vapour, not heat, so the kitchen still needs adequate general ventilation, particularly during long, high-volume services. The UltraVent Plus adds some running cost through filter replacement. For kitchens producing a lot of smoke, the UltraVent Plus or a traditional ducted canopy is the better option. Neither hood is completely hands-off, but for the right kitchen, both remove a significant installation barrier.
Questions to Ask Before Installation
Before specifying ventilation for a combi oven installation, it's worth working through the following:
What is the cooking application? High-temperature roasting and protein cooking generates more grease-laden vapour than steaming or regeneration. Higher-emission applications require more robust extraction.
What size oven is being installed? A 6-grid unit running at capacity produces significantly more exhaust than a 6-grid unit in light use. Volume matters.
Is there existing extraction infrastructure? If an overhead canopy is in place and correctly sized, an inline hood on the oven may simply need to connect to it. If there's no existing extraction, the scope of work is larger.
Are there structural constraints? Listed buildings, leased premises, basement kitchens, or temporary setups may rule out external ductwork — which is where ventless solutions earn their place.
Is the oven gas or electric? Gas units always require combustion ventilation. Electric units offer more flexibility, though steam management requirements remain.
What does your local authority require? Environmental health officers and building control teams have specific requirements that vary by location. For any installation involving external discharge, checking with the local authority early avoids expensive retrospective changes.
Summary
Most professional combi oven installations in the UK require some form of extraction. The type and extent of that extraction depends on the oven size, cooking application, kitchen layout, and regulatory context — but the baseline assumption should always be that ventilation is needed until you have a specific reason to conclude otherwise.
The good news is that the leading manufacturers have invested heavily in ventilation solutions that work across a wide range of installation scenarios. Whether you need a full overhead canopy, an inline UltraVent Plus, or a straightforward duct connection for a Convotherm or Lincat, there are well-proven options available.
If you're buying a refurbished combi oven through CaterCombi and have questions about ventilation for your specific installation, please get in touch. We work with kitchens across a wide range of environments and can help you understand what's required before the oven arrives on site.
