Should you close the flue to fireplace keep humidity out of house?

Closing a fireplace flue may help keep humidity out of the house, but it can also pose safety hazards. Here's why:

Reduced Ventilation: Closing the flue restricts airflow, which can impede proper ventilation in your home. This reduces the circulation of fresh air and may increase indoor humidity levels. As a result, moisture can accumulate in the house, potentially leading to dampness, mold growth, and other related issues.

Safety Concerns: Closing the flue can create dangerous situations and contribute to carbon monoxide (CO) poisoning. When a fireplace is in use, the flue needs to be open to ensure proper release of combustion gases, including carbon monoxide. Keeping the flue closed while the fireplace is burning creates a risk of CO buildup in your home, which can be life-threatening.

Increased Energy Consumption: Closing the flue, especially when the fireplace is not in use, can negatively impact your home's energy efficiency. An open flue allows warm air and moisture to escape from the house, preventing it from recirculating and increasing energy consumption. Keeping the flue closed may cause the house to feel stuffy and humid, requiring more air conditioning or other cooling efforts to maintain comfort levels.

Moisture Mitigation: While closing the flue can be an attempt to control indoor humidity, it's essential to address the root causes of excess moisture in your home. It's important to identify and fix any leaks or moisture sources, such as leaky faucets or poor roof insulation. Additionally, using proper ventilation systems, such as bathroom exhaust fans and kitchen range hoods, can help manage indoor humidity and prevent moisture build-up.

Instead of relying on closing the fireplace flue to manage humidity, it's better to focus on improving overall indoor air quality and addressing moisture issues effectively. Regular inspections and maintenance of your fireplace and ventilation systems, along with proper home insulation, can help maintain a comfortable and healthy living environment. If you're concerned about humidity in your house, consider consulting with a qualified HVAC technician or a home inspector to identify and address the specific sources of excess moisture.