Is Poor Utility Room Ventilation Putting You in Danger?
One thing that surprises many people is that in order to cause natural gas to efficiently combust, you need approximately 10 times the volume of air to the volume of natural gas. Air is essential to proper combustion and that is why proper utility room ventilation is essential to make a furnace, boiler, or water heater work properly and safely.
Why do I say safely? Bear with me a little bit here as it requires some basic chemistry. When natural gas and air are mixed in proper ratios and an ignition source is introduced, the byproducts of combustion are a flame, water vapor and carbon dioxide or CO2. Carbon dioxide is a gas made up of one carbon molecule and two oxygen molecules. However, when there is not enough air to supply an appliance to ensure proper combustion of natural gas, you get an incomplete and inefficient combustion which leads to the creation of carbon monoxide or CO. Carbon monoxide is a gas made up of one carbon molecule and one oxygen molecule which make sense since if you have less air you have less oxygen and hence CO is created versus CO2.
As you may already know, carbon monoxide is a dangerous gas that can be fatal if inhaled in large enough quantities. Incomplete combustion and the generation of carbon monoxide is absolutely not ideal when it comes to your furnace running. That is why it is critical to have your utility room properly sized or ventilated to ensure there is enough available air to make a complete combustion and hence keep carbon monoxide generation to a minimum.
So how do we appropriately ensure that a utility room is properly sized or ventilated to ensure proper combustion? Per several mechanical codes, approximately 50 cubic feet of air is needed for each 1000 BTU of total appliance input. Just to clarify, if your utility room has 2 gas burning appliances that means you must add the BTU rating for both of them. For example, If you have a 75,000 BTU gas furnace and a 25,000 BTU water heater your total input would be 100,000 BTU. Hence you would need 5000 cubic feet of air to ventilate the space. For a room with a 10 foot ceiling, that’s approximately a 22’ x 22’ room. For basements that are unfinished you may not need to take additional precautions, but that is larger than most utility rooms.
Figure 1 – Proper installation of Utility Room Ventilation
Figure 2 – Louvre Door to a utility room
If your utility room is small and enclosed, then the fix is very simple. All you need to do is add two vents, one within 12 inches of the ceiling and the other within 12 inches of the floor to add the necessary combustion air to enter your utility room (See Figure 1 above). Another option is to install a louvered door as shown below to allow enough fresh air into the room (See Figure 2 above).
Proper utility room ventilation is a serious matter and I hope this article enlightened you on the dangers of not ensuring your gas burning appliances have enough combustion air. It is also recommended to have CO detectors near every gas burning appliance so you and your family are able to get out of the house and not be poisoned by carbon monoxide. If you are unsure about your utility room set up and your need to add more ventilation to the room, I recommend calling a licensed home inspector or HVAC company to assess your situation and make recommendations.