A range vent hood is an important appliance that helps remove steam, grease, odors, and smoke from the kitchen during cooking. But when a range hood starts leaking cold air back into the kitchen, it can make your stovetop cooking experience rather unpleasant. Cold drafts blowing back at you is not only uncomfortable but can also lead to safety and health issues.
So what can you do if you notice your range hood leaking cold air? Here are some effective troubleshooting tips and solutions.
Inspect the Range Hood Filters
The first thing to check is the range hood filters. Grease and grime can build up on the metal filters over time. Excessive grease deposits can clog the filters, obstructing proper airflow and causing the vents to blow cold air back into the kitchen.
Follow these steps to inspect and clean the range hood filters:
- Locate the metal filters along the underside of the range hood. They are usually held in place by clips, springs or frames.
- Carefully remove the filters and inspect for grease buildup. Soak excessively greasy filters in hot soapy water and scrub off the deposits with a brush.
- Rinse and dry the filters completely before reinstalling them. Replace highly greasy or damaged filters.
- Check the manufacturer’s manual for recommended cleaning frequency. Cleaning filters every 2-3 months helps prevent obstructions.
Proper filter maintenance allows for unrestricted airflow and prevents cold drafts from the range hood vents.
Check the Damper Flap
Another common source of reverse airflow is a faulty damper flap. Range hoods have an internal flap that prevents outside air from flowing back into the kitchen.
Examine the damper flap to ensure it can open fully when the hood fan turns on, and close tightly when the fan is off. A flap that is stuck open will continuously leak cold air back through the vents.
A damaged, warped or missing damper flap has to be repaired or replaced. Consult a technician if you are unable to access the damper flap for inspection.
Look for Leaks Around the Ductwork
Poor connections or leaks in the ductwork can also lead to the range hood blowing cold air into the kitchen.
Inspect along the entire length of the ductwork from the range hood to the outside vent opening. Look for signs of:
- Detached or loose duct connections
- Rips, holes or cracks in the duct material
- Inadequate insulation leading to cold air infiltration
Use aluminum foil tape to seal minor tears in the ductwork. For larger gaps, you may need rigid aluminum/metal pipes and clamps to reconnect any detached duct sections. Insulating the ducts can help prevent cold air leaks.
Hire a professional if you need major ductwork repairs or replacements.
Check for Proper Ventilation
Range hoods require proper ventilation to function optimally. Problems like accumulated debris, birds nests, extremely cold outside temperatures, etc. can obstruct the outside wall or roof vent.
Examine the termination point of the ductwork to make sure there is no blockage. It should have a ventilation hood with a back-draft damper to facilitate air outflow while preventing wind, debris and animals from entering the ducts.
Clear any obstructions from the outside vent. Hire a contractor to install a vent hood if your ducts just outlet into open space. Proper ventilation allows smooth air extraction, reducing the chances of reverse cold airflows.
Adjust the Blower Settings
If the hood vents are still blowing cold air even after inspecting the ducts and filters, the blower settings may need adjustment.
First, set the blower speed to the highest setting. Stronger airflow can help eliminate reverse drafts.
Next, check whether the problem occurs only when the blower is running on low speeds. If so, avoid using the low blower speeds. Stick to medium or high fan settings to ensure the airflow is strong enough.
Some range hoods also have backdraft dampers built into their blowers. Adjust these dampers to reduce reverse airflows. Check the installation guide to locate any damper adjustment knobs.
Getting the blower configurations right can prevent cold backdrafts through the range hood.
Seal Air Leaks Around the Hood
Cold drafts can also leak through gaps and crevices around the range hood installation.
Inspect the joints between the range hood and walls/ceiling for any separation gaps. Also check exhaust vents, plumbing openings, returns, etc. nearby that can potentially leak air.
Use non-combustible metal foil tape to seal any gaps found near the range hood. Caulking or expandable foam can help seal plumbing openings and returns behind the hood.
Proper sealing isolates the hood and minimizes air leaks that contribute to blowing cold air into the kitchen.
Is it Time to Replace the Unit?
If you have inspected and tried all the above troubleshooting tips but the range hood still leaks cold air, it may be time to replace the entire unit.
Look for the following signs that indicate your range hood needs replacement:
- Excess rust and corrosion on the hood and internal parts
- Clogged vents that cannot be cleaned
- A very underpowered, noisy blower motor
- Faulty electronic controls
- Major ductwork damage
Range hoods typically last 10-15 years with proper maintenance. Units exposed to heavy use and inadequate ventilation tend to deteriorate sooner.
Consult a kitchen remodeling contractor to install a replacement range hood that properly matches your cooking appliance, kitchen size and ventilation needs. This can resolve the reverse cold air issue.
FAQs About Cold Air Leaking Range Hoods
Q: Why does my range hood blow cold air even when the blower is off?
A: This indicates a problem with the damper flap not closing properly when the blower is off. Inspect the flap and fix or replace it if damaged. Sealing gaps around the hood can also minimize uncontrolled air leaks.
Q: Can improper duct sizing cause a range hood to leak cold air?
A: Yes, undersized ducts lead to insufficient airflow, allowing cold air to blow back into the kitchen. Ensure the ductwork meets the recommended sizing for optimal air extraction.
Q: My range hood vents air outside. Should I still insulate the ducts?
A: Yes, adding insulation around ducts that vent outside helps minimize cold air infiltration during windy weather or extremely low temperatures.
Q: Does a ductless/recirculating range hood also pose a cold air leak risk?
A: Yes, a recirculating range hood with clogged filters can still leak cold air through gaps around the unit. Proper installation and sealing is important regardless of ducted or ductless design.
Q: Can I temporarily stop my range hood from leaking cold air using duct tape?
A: Avoid using duct tape as it is not very durable and loses adhesiveness over time. Use high quality metal foil tape to temporarily patch small leaks until major repairs can be done.
Q: My range hood has an air intake vent. Should this be closed to prevent cold air leaks?
A: No, closing intake vents can disturb proper airflow. They are designed to allow ambient air entry to prevent air pressure imbalances. Keep intake vents open while sealing actual cold air leak points.
Conclusion
A range hood that blows cold air back into the kitchen can make cooking unpleasant. But in most cases, the problem can be fixed with some DIY troubleshooting and repairs like cleaning filters, sealing leaks, adjusting blower settings, etc. For major issues, hiring a professional may be needed to replace damaged parts or the entire range hood unit. Addressing the cold air leaks promptly improves your cooking comfort and also prevents potential moisture buildup issues.