By Paul Bianchina
Q: I have a small apartment in my basement that I rent out. The tenant cooks with high heat and a lot of oil, and now there is a strong smell coming up from the apartment, and everything is covered with grease. We are cleaning up, and now I want to install a range hood. What is the minimum CFM you would recommend for this, and will it take care of the grease problem?--Diane S.
A: Opinions vary somewhat on how many cubic feet per minute (CFM) is required for spot ventilation devices such as a range hood, but 100 to 150 CFM is the airflow number most commonly used. Don't go too much larger than that, since getting a unit with an excessive amount of CFM can create drafts around windows and doors, and can cause back drafting problems from combustion appliances. Remember that the hood must be vented outside the building.
A range hood will help with some of the grease problems, but will not solve all of them in the situation you describe. Due to the weight of the grease particles and their tendency to stick to surfaces, a certain amount is always going to escape into the air and onto surrounding surfaces. Commercial ventilation equipment is the only thing that would really help here, but that's both expensive and impractical for a small apartment.
The other issue here is that your tenant also has responsibilities. It is extremely important that the grease filter on the hood be cleaned regularly, and if he is not doing that, then any size hood will quickly become ineffective. The combination of oil and high heat that you describe is a recipe for disaster, and both you and your tenant need to be aware of the potential health and safety issues involved here, especially in an older building. I would strongly suggest that you have a licensed heating and ventilation contractor install the hood and inspect the premises for other potential ventilation problems.
Finally, please be sure that your basement apartment has the code-required emergency egress, and that you have working smoke detectors in the apartment and in your home. If you have combustion appliances such as those that use natural gas, you should also install carbon monoxide (CO2) detectors. I would also suggest that you contact your local fire department for other safety recommendations.
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