Upblast vs Downblast Roof Fans: The Difference

Posted on Nov 15, 2021

Ventilation is a crucial part of any enclosed space, especially when you have fumes, moisture, odors, heat and grease-filled air that needs to be taken out. Commercial kitchens, laundries, and bathrooms are some areas that will need ventilation, so it’s vital to know which fan to use for the best result.

There are two types of exhaust fans, upblast and downblast fans. Both play a crucial role in ventilating any enclosed space, but it all boils down to which type you need depending on your unique situation. We should be able to make an informed decision once we have evaluated each option and know what they offer.

Upblast Roof Fans Explained

Upblast roof fans are roof fans that pull air out from your property. They come with different types of hoods and different types of motors, but the one thing that they all have in common is that they pull the contaminated air out. A good upblast fan can take all of the fumes, odors, warm air, and vaporized grease out before they spread to the other areas of your property. With a good upblast fan, the air quality in your property will improve, and you won’t have to worry about people getting sick from all of those fumes.

Advantages of Upblast Roof FansĀ 

  • Contaminated air is directed up and out of the area.
  • They create a negative pressure space to prevent the smoke, odors, and warm air from escaping into other parts of your property.

Disadvantages of Upblast Roof Fans

  • While they can direct air out quickly, the air that takes the place of the displaced air might come from unwanted sources like an open window or an adjacent room that may also have contaminated air.
  • Since they tend to create a negative pressure space, doors and windows might be harder to open since the pressure outside is greater than the pressure inside.

Downblast Roof Fans Explained

In contrast, downblast roof fans pull air from the outside into a room to fill it with fresher, cooler air for improved air quality. Like upblast roof fans, they also have different kinds of hoods and motors, but all downward roof fans force air into the property, which can help with air circulation. A good downblast roof fan can keep a steady flow of fresh and temperature-controlled air into the room. Consequently, your air conditioner will work less, and your overall energy usage will be lower since the temperature will be more evenly distributed.

Advantages of Downblast Roof Fans

  • Preferred (cooled and filtered outside air) is forced into the room.
  • Since the air coming into the area is controlled, you have the option to adjust the temperature, airflow, and humidity levels depending on your needs.

Disadvantages of Downblast Roof Fans

  • Even if the air coming in is temperature-controlled and filtered, it will mix with the contaminated air of the room, which might render it useless.
  • It creates a positive air pressure in your desired area. However, it might allow the contaminated air to go to other parts of your property, which can be unpleasant.

Which exhaust fan is right for you?

The right roof fan for your application depends on a lot of factors. One factor to consider is the overall air pressure of the room. Do you want to have negative or positive air pressure? Maybe you need a balance?

You can have only one of the two, but have you considered having both? After all, you need a balance of air coming in and out of your kitchen. You want cool and filtered air to come in while you need to take out the warm contaminated air.

We want to create a comfortable, clean, and cool air quality for your room. Having both upblast and downblast fans provides you both advantages and none of the problems we’ve discussed. More often than not, it requires both types of roof fans to achieve a balanced air pressure or a little negative pressure that ensures polluted and heated air rises and is sucked out of your kitchen.

Nonetheless, knowing the advantages and disadvantages of each fan will help you make a decision on the right kitchen exhaust system depending on your specific needs.