Why cooker hood extraction rates matter

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Why cooker hood extraction rates matter

The right extraction rate keeps your kitchen air clean, tackles steam, odours and grease, and helps prevent condensation and lingering smells in open-plan spaces. This guide explains how to size a cooker hood for your room, what affects real-world performance, and how to balance noise with airflow for everyday cooking.

Important: As a rule of thumb, aim for around 10–12 air changes per hour (ACH). That’s your kitchen’s volume (length × width × height) multiplied by 10–12 to find a minimum extraction rate (m³/h). We’ll walk through the maths shortly.
  • Understand what extraction rate (m³/h) means for kitchen ventilation.
  • Quickly size a hood with the 10 ACH formula and a simple calculation.
  • Adjust for real homes: duct length, bends, and filter type.
  • Choose between ducted extraction and recirculating set-ups.
  • Balance airflow, noise (dB), and energy efficiency.
Tip: If your calculation sits between sizes, pick the model with a slightly higher extraction rate. Running it on a lower speed is usually quieter and still efficient.

Interactive Cooker Hood Extraction Rate Calculator

Quickly size your hood using the 10–12 air changes per hour rule, then fine-tune for open-plan layouts, island hoods and ducting quality.

Rule of thumb for extraction rate: Volume × ACH
Compensates for capture from multiple sides.
How it works: We compute kitchen volume (L × W × H), multiply by your chosen ACH, then apply adjustments for layout, ducting and mode. Results are rounded to the nearest 50 m³/h.
Tip: If your result falls between sizes, choose the model with the higher extraction rate. You’ll hit your target at lower, quieter speeds.

💡 Did you know?
Most cooking odours settle within 10 minutes — a well-sized hood clears them before they spread through your home.

What is Cooker Hood Extraction Rate?

The extraction rate of a cooker hood tells you how much air it can remove from your kitchen in an hour. It is measured in cubic metres per hour (m³/h). The higher the number, the more powerful the hood is at clearing steam, odours, and grease particles.

Note: An extraction rate of 500 m³/h means the hood can move 500 cubic metres of air in one hour – roughly enough for a medium-sized kitchen.

Ducted vs Recirculating Modes

Not all cooker hoods work in the same way, and their performance depends on the type of installation:

  • Ducted Extraction – Air is drawn through filters and expelled outside via ducting. This provides the best airflow and odour removal.
  • Recirculating – Air passes through grease filters and carbon filters before being released back into the kitchen. These are easier to install but typically less powerful and rely heavily on filter condition.
Tip: If you can, opt for ducted extraction. Even with a lower extraction rate, it often outperforms a higher-rated recirculating hood.

💡 Did you know?
Recirculating hoods lose efficiency as carbon filters become saturated – replacing them regularly is key to performance.

Next, we’ll show you exactly how to calculate the recommended extraction rate for your kitchen using a simple formula.

How to Calculate the Recommended Extraction Rate

The easiest way to size a cooker hood is with the 10 air changes per hour rule. Your hood should refresh the air in your kitchen around 10–12 times every hour for effective ventilation.

The Formula

Kitchen volume (length × width × height) × 10 = Minimum extraction rate (m³/h)

By multiplying your kitchen’s volume by 10, you get the minimum extraction rate needed. If you cook frequently or have an open-plan layout, aim closer to ×12.

Example Calculation:
Kitchen size: 5m (length) × 4m (width) × 2.5m (height) = 50 m³
50 × 10 = 500 m³/h minimum extraction rate

Why 10 Air Changes?

This standard balances performance and noise. At lower speeds, a hood can still meet the required rate while staying quieter. Oversized hoods can be run on eco or mid settings for everyday use.

Tip: Always round up when choosing a cooker hood. If your calculation is 480 m³/h, a hood rated at 500–600 m³/h will perform better without needing maximum power all the time.
💡 Did you know?
Running your hood on lower speeds most of the time reduces noise and energy use, while still hitting the recommended air changes.

Next, let’s break this down into a simple extraction rate table by kitchen size so you can check your requirements at a glance.

Other Factors That Affect Cooker Hood Performance

Even if your hood has the correct extraction rate for your kitchen, several real-world factors can reduce its efficiency. Understanding these helps you get the best from your appliance.

Key Influences on Extraction

  • Duct length and bends – The longer and more twisted your ducting, the harder it is for air to flow. Each bend can reduce efficiency by up to 10%.
  • Filter type and condition – Metal grease filters should be cleaned regularly. Carbon filters in recirculating hoods need replacing every 3–6 months for consistent performance.
  • Cooking style – Heavy frying, grilling, or wok cooking produces more vapours, requiring higher extraction rates than boiling or simmering.
  • Hood placement – Island hoods often need stronger extraction than wall-mounted hoods because they capture air from all sides.
Important: Always use the correct duct size recommended by the manufacturer. Narrow ducts or makeshift reductions can drastically reduce airflow and increase noise.

Balancing Noise and Efficiency

Many people avoid using their hood’s highest setting because of noise levels. Choosing a model with a slightly higher extraction rate allows you to run it on mid-settings – quieter, yet still effective.

Tip: Install smooth, rigid ducting instead of flexible hose wherever possible. It improves airflow and reduces turbulence, keeping noise lower.
💡 Did you know?
Every 90° bend in your ducting can cut airflow by around 10%. Keeping runs straight makes a huge difference.

Next, we’ll explore some of the common mistakes people make when choosing extraction rates, and how to avoid them.

Common Mistakes When Choosing Cooker Hood Extraction Rates

It’s easy to get confused when comparing cooker hoods. Many homeowners either underestimate or overestimate the power they need. Here are the most frequent pitfalls to avoid:

Typical Errors

  • Buying a hood that’s too weak – If the extraction rate is below your kitchen’s minimum requirement, steam and odours will linger.
  • Ignoring duct restrictions – Long duct runs, multiple bends, or using the wrong duct size can reduce the hood’s advertised performance.
  • Confusing noise with efficiency – A quieter hood isn’t always weaker. High-quality models achieve strong airflow at lower decibel levels.
  • Focusing only on aesthetics – Slimline or decorative hoods may look stylish but sometimes compromise on airflow if not properly matched to the room size.
  • Not accounting for open-plan layouts – Large open kitchens need a higher extraction rate than enclosed ones of the same size.
Note: Manufacturer ratings are tested in ideal conditions. Real-world performance can drop by 20–30% depending on installation. Always allow some margin above the minimum.

Why These Mistakes Matter

Choosing the wrong hood can lead to persistent smells, grease build-up, higher energy use, and a noisier kitchen environment. Getting it right first time saves money and frustration.

Tip: If in doubt, choose a cooker hood with a slightly higher extraction rate. It gives you flexibility and avoids underperformance in busy cooking sessions.
💡 Did you know?
Running a hood on maximum all the time is a sign it may be underpowered for your kitchen size.

Next, let’s look at some practical tips for choosing the right cooker hood to match both your kitchen and cooking style.

Tips for Choosing the Right Cooker Hood

With so many options available, it’s important to choose a hood that not only looks good but also delivers the right extraction performance for your space. Here are some expert tips to guide your decision:

What to Look For

  • Match the extraction rate – Use the 10 air changes rule as a minimum. For open-plan or heavy cooking, go higher.
  • Check fan speeds – Multiple speed settings let you adjust power and noise depending on what you’re cooking.
  • Consider noise levels – Look for a balance of m³/h and dB ratings. A higher extraction hood often runs more quietly at mid-settings.
  • Energy efficiency – An A-rated cooker hood uses less electricity without sacrificing airflow.
  • Size and coverage – The hood should be at least as wide as your hob, ideally a little wider for maximum capture.
  • Filter maintenance – Easy-to-clean grease filters and accessible carbon filters make upkeep simpler.
Important: If your kitchen has unusual dimensions or restricted ducting, consult the manufacturer’s technical guide. Some hoods are designed for extra power or ducting flexibility.

Balancing Style with Performance

While it’s tempting to focus purely on design, remember that function should come first. A stylish but underpowered hood will quickly become frustrating. Always prioritise extraction rate, then narrow down by design and finish.

Tip: For island kitchens, choose a more powerful model than the calculation suggests – they need extra pull to capture rising air from all directions.
💡 Did you know?
A cooker hood’s effectiveness isn’t just about power – correct installation height above the hob makes a huge difference.

Next, let’s answer some of the most common questions people have about cooker hood extraction rates in an easy-to-use FAQ section.

Frequently Asked Questions About Cooker Hood Extraction Rates

Still unsure about the right extraction rate for your kitchen? Here are answers to the most common questions homeowners ask when choosing a cooker hood.

Aim for 10 air changes per hour (ACH) in a standard kitchen. For open-plan spaces or heavy cooking, target 12 ACH for better odour and steam capture.
Use: Room volume × target ACH = required m³/h.
Example: 4m × 3m × 2.4m = 28.8 m³. For 10 ACH → ~290 m³/h. For open-plan at 12 ACH → ~345 m³/h.
m³/h is most common. Quick converts: • m³/min = m³/h ÷ 60 • L/s ≈ m³/h × 0.278 (e.g. 600 m³/h ≈ 10 m³/min ≈ 167 L/s)
Yes. Keep runs short, use smooth-walled 150mm duct where possible, and minimise elbows/bends. Each bend adds resistance and reduces the effective m³/h.
No. Recirculating hoods can move similar airflow (m³/h) but they don’t remove moisture and rely on filters for odours. For the best extraction rate and humidity control, choose ducted if possible.
Higher fan speed = higher m³/h and more noise. For quiet running, use a hood with a good base airflow and large duct diameter; run on low/medium for most cooking and use boost briefly when needed.
Go higher: 12 ACH. Choose a hood with a wide capture area (ideally 10cm wider than the hob on each side) to help contain rising fumes in open spaces.
Real-world flow depends on installation: undersized or flexible ducting, long runs, back-drafts, blocked filters, or too many bends all reduce the effective extraction rate. Optimise ducting and keep filters clean.
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