Backdrafting may be something you think of in relation to fires. While it is indeed a common term within firefighting to describe when a fire has consumed all available fuel and then suddenly explodes when more oxygen is available, it is also a term used when discussing large household appliances and HVAC (heating, venting, and air-conditioning) systems. Let’s examine what backdrafting is so you will become a savvy home or building owner.
What is Backdrafting?
Backdrafting occurs when the combustion gases of a fuel-fired appliance meant to flow outside the home are, instead, drawn into the living spaces. Because many fuel-fired water heaters and boilers depend on household air for combustion, they can become vulnerable to backdrafting if and when indoor air pressure becomes low. It is hazardous, as it can send fatal carbon monoxide gas into the home. Carbon monoxide is a silent killer – it is odorless and colorless.
How Can You Tell if Backdrafting Has Occurred In Your Home?
Since backdrafting can quickly become a health and home emergency, knowing what to look for is crucial.
Here are some signs of backdrafting:
- A triggered carbon monoxide detector
- Smoke odors
- Stale air
- Yellow burner flames
- Pilot light extinguishing
A properly installed carbon monoxide detector – One of the best ways to protect yourself, especially as the first line of defense, is to install a carbon monoxide detector. When backdrafting occurs in a furnace or water heater, one of the most dangerous things can be the release of carbon monoxide into the home. With a CO detector, you and your home’s occupants will be immediately alerted to this potentially fatal threat.
Smoke odors in the home – If you begin to notice smoke odors in your home, this is usually a sign of backdrafting. Smoke that should be vented outside, perhaps from your fireplace, is being pulled back into your house.
Stale, stuffy air inside your house – Another typical sign of backdrafting is the air within your home beginning to feel and smell stale and stuffy. This is because the inside air is not properly venting to the outside.
Burner flames yellow instead of clear blue – If the burner flames on natural gas-fired appliances such as your furnace, water heater, or stove are showing as mostly yellow instead of clear blue, this can be an indication of backdrafting.
Pilot light going out – If your pilot light is continually going out, this is another symptom of backdrafting. The draft could be blowing it out.
How Can You Test to See if Your Furnace is Backdrafting?
1. Turn the heat down
2. Close all windows and doors
3. If you have any fireplace dampers, close them
4. Turn on all kitchen and bathroom exhaust fans
5. If you have a clothes dryer, turn it on
6. Run enough hot water in your bathtub so that your water heater turns on
7. Hold a lighter or lit incense stick about three inches from the draft hood of the furnace.
The smoke from the lighter or incense stick should be immediately wicked away. If the smoke instead spills into the room for more than 30 seconds, you have a backdrafting issue.
How Can I Eliminate Backdrafting in a Gas Heater?
- Reduce by-products
- Energy efficiency
- Air supply
- Fireplace
- Backdraft damper
Reduction of combustion by-products – It is of primary importance to ensure that your heater is burning fuel properly so that hazardous combustion gases will be minimized. Having an annual checkup by an HVAC professional is the best way to ensure that your heater is running at its very best.
They will check to make sure that your burner jets have no clogs, and they will also verify the gas pressure. Such issues could cause low pressure, such as a defective gas meter regulator or a leak in the buried gas line. Any of these could cause incomplete combustion and excess carbon monoxide production, which could create a deadly outcome for the home’s occupants.
Home too energy efficient – As odd as it sounds, having a too-energy-efficient home might hurt you regarding backdrafting. A home that is too tightly sealed can allow a situation where there is so little outdoor air entering the home that the exhaust fans of the kitchen and the bathroom, when turned on, can induce negative pressure. Combustion gases that usually flow up and out of the heater exhaust fan are pulled back down and into the home’s living spaces.
Supply ducts leaking air – It is crucial to ensure that all leaky ducts that vent into unconditioned zones like attics or crawl spaces are sealed up. If not, the disparity between those and the well-sealed return ducts will create negative interior pressure, which will suck outdoor air through any openings, including heater vents. As a result, those dangerous combustion gases that need to be exhausted will, instead, be pulled back into the home.
Fireplace use – Anytime a fireplace is used, it can quickly depressurize a house and cause backdrafting. A quick fix for this can be to partially open a window anytime a fireplace is in use.
Make sure to have backdraft dampers installed – This is of critical importance. Your HVAC professional will install a backdraft damper with your furnace.
What is a Backdraft Damper and How Does it Work?
Backdraft dampers allow for the expulsion of bad air out of the house and then close to protect the building from allowing it back in. Thus, exhaust, bacteria, and odors are removed, with none of the contaminated air returning to the HVAC system.
Backdraft dampers open with regular air flow and close with the help of gravity. They are an integral part of a safe, functional HVAC system and will protect your appliances, your home, and the safety of all the occupants.
Like fire dampers, backdraft dampers are crucial to protecting people from household hazards. When looking for a reputable place to purchase your HVAC supplies, look to trusted industry professionals like Lloyd Industries. From fire dampers and brick vents to security bars and stud protectors, we have got you covered. Once you’ve made your choice, we have a list of trusted professionals to help you get everything installed.
