Range hoods are arguably one of the most essential kitchen appliances. They perform the important function of removing airborne grease, smoke, odors, and other air pollutants from the kitchen.
In addition to their primary function, kitchen range hoods can also affect the temperature in a room.
Range hoods can help cool a room if they are ducted and outdoor temperature is lower than indoor temperature. The range hood exhausts hot air. Replacement air is pulled in from outside through open windows and doors. If this air is cooler, it cools the room. If the cross breeze is strong, there is wind chill.
Range Hood Can Cool Room Under Certain Conditions
Range Hood Must Be Vented
Range hoods can either be ducted or ductless. A ductless range hood doesn’t expel air outdoors. Instead, it filters impurities from the air and then recirculates the air back into the room.
Ducted range hoods function differently. They are connected to a duct that removes air containing impurities and heat from the kitchen and exhausts it to an outdoor location.
Here is a post about how to tell if your range hood is ducted or ductless.
The process of removing air from the room creates negative air pressure in the space. Negative air pressure is otherwise known as a vacuum, and whenever air is removed from a room, an equal amount of air must be drawn in to eliminate the vacuum or the negative pressure.
This causes air to be pulled into the room from outdoors through open windows and doors or from other parts of the house (as this air is drawn or from these parts of the house, outdoor air is pulled in at these points to prevent a vacuum).
For a range hood to be able to cool a space, there has to be a flow of air in and out of the room. This isn’t possible with ductless range hoods, so before you attempt to cool your room with a range hood, first ensure that it vents outdoors.
Outdoor Temperature Lower Than Indoor Temperature
Having a ducted range hood doesn’t guarantee that the range hood would cool your room.
It isn’t just about drawing air into the room; it’s about drawing in cool air. What this means is that a range hood would only be able to help cool a room if the outdoor temperature is considerably lower than the temperature indoors.
For instance, the air that would be pulled into the house on a hot summer afternoon might actually make the room hotter if you’ve got good insulation or your kitchen is on the shady side of the house.
So, for this system to work, you need to ensure that the air being drawn into the house is cooler than what is being removed from the room. You can do this by first assessing the outdoor temperature.
Best Setup
The effectiveness of the range hood in drawing in cool air is dependent on how much warm air is removed from the room. So, you should make sure that your range hood is strong enough for the size of the room. Cooling your kitchen is, of course, just a secondary benefit of sizing the range hood correctly; the primary benefit is effective ventilation.
Depending on the size of the room and the CFM of the range hood, you might need to run a make-up air system. But if you do not have one, open the windows and door in the kitchen, preferably those opposite the range hood for improved airflow.
The extent to which you benefit from the cooling effects of your range hood depends on where you are in the room. You will enjoy the most benefits if you put yourself in the path of the cross breeze because you will also benefit from wind chill.
So, try to open windows and doors that would mean the breeze passes over the central area or the area where you spend the most time.
Using this system in an enclosed kitchen means that you would only enjoy the cooling effect in the kitchen. If you have an open plan setup, then you can use it to cool a larger area by opening up the windows and doors on the opposite side of the space to the range hood.
Timing is Key
Regardless of the temperature outdoors, air will be drawn into the house as long as the range hood is removing air from the room.
So, to ensure that you aren’t filling your room with warm air or air that shares a similar temperature as your room, make sure that you use this system only when the temperature outdoors is lower than that of the room.
As a general rule, the greater the temperature difference, the more effective the range hood would be in helping you cool your space.
The best time to run the rage hood for this purpose is at night with a few strategic windows open. Don’t run it overnight if the owner’s manual gives a shorter continuous running time.
Experts claim that the coolest time of the day is the period just before dawn. So, if you’re really committed, you could get up early, open a window, turn on the range hood, and properly wake up to a cooled house.
If you decide to run the range hood overnight, ensure that you close the windows just after dawn so that hot air doesn’t come in and negate what you achieved overnight.
Benefits of Using Range Hood to Cool Room
- Using a range hood to cool a room is more cost-effective than running an AC. On average, a medium-sized window AC uses about 500 W per hour, while a range hood consumes about 100 W every hour. This means that if electricity costs $0.13 per kWh, running an AC for an hour would cost about $0.117 while using a range hood for the same time frame would cost only $0.013.
- The range hood removes hot air from the room as well as draws in cooler air, thus helping to keep indoor air comfortable.
- Besides helping to cool the room, range hoods also remove impurities from the air and improve the air quality in the room.
- It allows you to give your AC a break if you have one. If you don’t, it may prevent the necessity of installing an AC.
Drawbacks of Using Range Hood to Cool Room
- Range hoods are designed to remove hot air and impurities from a kitchen. So, although their activities can cause cool air to be drawn into a room, the range hood itself isn’t a cooling unit and is, therefore, not as effective as cooling units.
- They cannot help cool a space when the temperature outdoors is high. Instead, they would cause warm air to be drawn inside to further increase the heat in the room. This means that they would be ineffective on hot afternoons when you need to cool your house the most.
- The range hood would not be able to cool a room if cold air isn’t coming in from the outdoors or from other parts of the house.
- Using a range hood for prolonged periods can cause significant wear to the motor and can even lead to a fire.
- Some range hoods are noisy.
Tips
- Only use a range hood for this purpose when the temperature outdoors is significantly lower than the indoor temperature.
- If you are to use the range hood through the night, do not run it at high settings. Instead, use a low setting. This way, you do not put so much strain on the motor.
- If you run the range hood through the night, turn it off before daybreak so that warm air isn’t drawn into the room as the outdoor temperature increases.
- Use a fan by an open window to pull more air into the room.
- For improved performance, clean the range hood filter once every month.
- Range hoods with higher CFMs tend to remove more air. So, if you use this type of range hood in a small room, you might end up pulling out more air than what can be drawn back into the room. Thus, if you are going to be running the range hood for long, ensure that it is suitable for the size of the room.
- Don’t use the range hood with an AC. Unlike ACs and ceiling fans, which enhance each others’ effect, range hoods will cancel out the effects of the AC because all the cooled air would be exhausted outside.
If you’re looking for alternative ways to cool your house, the you might also be interested in my article on Does a Bathroom Exhaust Fan Help Cool the House.
Sources
https://www.ambientedge.com/blog/exhaust-fans-suck-heat-right-out-of-your-home/
https://www.hvac.com/humidity/exhaust-fans-essential-home-comfort/
https://rangecraft.com/exhaust-fans-for-cooling-a-room/#
https://learn.compactappliance.com/range-hoods-ducted-vs-ductless/