A kitchen without proper ventilation quickly fills with smoke, grease particles, heat, and lingering odors. The single biggest mistake people make when buying a kitchen exhaust fan isn't picking the wrong brand — it's picking the wrong size. A fan that's too small will struggle to clear the air, while an oversized fan wastes energy and creates unnecessary noise. Here's a simple guide to help you choose the right one, along with the options available from our range.
Why Size Matters
Exhaust fans are rated by airflow capacity, but the practical way to choose one is by matching it to your kitchen's floor area. A fan sized correctly for your space will:
- Clear smoke and cooking odors quickly
- Reduce grease buildup on walls and cabinets
- Improve indoor air quality
- Run efficiently without excess noise or power consumption
Step 1: Measure Your Kitchen Area
Start by measuring the square footage of your kitchen (length × width). This is the single most important number when selecting a fan, since airflow requirements scale with room size.
Step 2: Match the Area to the Right Fan Capacity
Based on this, here are the fan options we offer, grouped by the kitchen size they're designed for:
60–150 Sq Ft — Model AHT15-34
Ideal for small to medium kitchens. This setup includes:
- AHT15-34 exhaust fan unit
- 2 x 6" Diffusers
- 1 x 8" Outer Cowl
150–200 Sq Ft — Model AHT20-55
Suited for medium-sized kitchens with higher cooking activity. This setup includes:
- AHT20-55 exhaust fan unit
- 3 x 6" Diffusers
- 1 x 8" Outer Cowl
200–250 Sq Ft — Model AHT20-65
Built for larger kitchens or commercial-style setups. This setup includes:
- AHT20-65 exhaust fan unit
- 4 x 6" Diffusers
- 1 x 8" Outer Cowl
Each package comes complete with the fan unit, the correct number of diffusers to distribute airflow evenly across the room, and an outer cowl to protect the external vent opening from weather and debris.
Step 3: Consider Diffuser Placement
Notice that as kitchen size increases, the number of diffusers increases too — from 2, to 3, to 4. Diffusers help distribute suction points across the ceiling so that smoke and heat are pulled evenly from all areas of the kitchen, not just from directly above the stove. Larger kitchens need more diffusers to avoid "dead zones" where air doesn't move.
Step 4: Don't Forget the Outer Cowl
The outer cowl is the external vent cover where exhaust air exits the building. All three of our kitchen fan packages include one 8" outer cowl, which protects the ducting from rain, dust, and pests while still allowing smooth airflow out of the kitchen.
Quick Reference Table
| Kitchen Size | Recommended Model | Diffusers | Outer Cowl |
|---|---|---|---|
| 60–150 Sq Ft | AHT15-34 | 2 x 6" | 1 x 8" |
| 150–200 Sq Ft | AHT20-55 | 3 x 6" | 1 x 8" |
| 200–250 Sq Ft | AHT20-65 | 4 x 6" | 1 x 8" |
Frequently Asked Questions
1. What size exhaust fan do I need for my kitchen? It depends on your kitchen's square footage. As a general guide: 60–150 sq ft kitchens suit the AHT15-34, 150–200 sq ft kitchens suit the AHT20-55, and 200–250 sq ft kitchens suit the AHT20-65.
2. What happens if I install an exhaust fan that's too small? An undersized fan won't be able to clear smoke, heat, and odors effectively. It will run constantly at full power, leading to higher energy use, faster wear, and a kitchen that still feels stuffy or smoky.
3. What happens if I install an exhaust fan that's too big? An oversized fan for a small kitchen can create excess noise, waste electricity, and in some cases pull conditioned air out of the room faster than needed, making the space feel drafty.
4. Why do larger kitchens need more diffusers? Diffusers spread suction points across the ceiling so air is pulled evenly from the whole room. Larger kitchens need more diffusers (3–4 instead of 2) to avoid dead zones where smoke and heat linger.
5. What is an outer cowl and do I need one? The outer cowl is the external vent cover where air exits the building. It protects the ducting from rain, dust, and pests. All of our kitchen fan packages include one 8" outer cowl.
6. Should I round up or down if my kitchen size is between two ranges? Round up. A slightly larger fan running on a lower setting is quieter and more efficient than a smaller fan working at maximum capacity.
Final Tip
If your kitchen falls right on the border between two size ranges, it's generally safer to size up rather than down — a slightly larger fan running at a lower, quieter setting will always outperform an undersized one working at full capacity.
Choosing the right exhaust fan doesn't have to be complicated. Measure your space, match it to the right model, and make sure diffuser count and outer cowl are included — and you'll have a kitchen that stays fresh, clean, and smoke-free.
