If you're going to get a new ducted range hood, you obviously want to get one with enough of power under the hood. However, when you pass a certain threshold in terms of power, by law you will be obligated to take certain precautions in order to prevent carbon monoxide poisoning, which can happen through something called backdrafting. To prevent this, you might have to provide range hood makeup air. Please read on for your own safety.
withhold this information, as could mean the difference between buying an expensive model and a cheap(er) one. Since we don't play that game at Rangehoodguide.com, please read on.
Like we've shortly mentioned before, some people immediately want to buy the biggest, baddest commercial grade range hood they can get their hands on and install it in their home kitchen. You might have a big family and therefore need to prepare a lot of big dinners. Others just want to impress their friends. A nice big and shiny range hood in the kitchen can be a great eye catcher, right? 1200 CFM? Make it 1600 CFM! Better to be safe than sorry, right? No. Not only would that be overkill for the average household and would consume large amounts of energy, it would actually be very dangerous to put it in your residential home without the proper precautions, as it will likely create a backdrafting problem. A what problem? Let us explain.
throughout the house (called backdrafting). However, due to houses becoming more and more air-tight and well-isolated, the range hood makeup air has to come from other places. In practice, this usually means it comes in through undesirable exhaust routes (e.g. fireplace, furnace, dryer vent, hot water heater), which might cause carbon monoxide and other harmful pollutants to be sucked into the house and cause (carbon monoxide) poisoning.
of your city's or state’s building code. However, check your own state’s building code, because the CFM threshold to supply makeup air may vary from state to state. (E.g. in the state of Minnesota the threshold is 300 CFM.)
Luckily, some manufacturers have started to design such range hood makeup air systems, so that people will be safe from harm by meeting the range hood code requirements. They usually include a sensor of some type which senses when to open up the damper and let the fresh air in. Example: