Should I Leave Interior Doors Open Or Closed During Heating And Cooling?

Recently, researchers have found out that simply keeping a bedroom door closed can adversely affect comfort, safety and health in a house. This is because it blocks the air’s pathway, thus reducing air flow into the room and through the system as well. Pressurization of the room, which is caused by air trapped within the space, forces the cool air out of the house. All this has a significant impact on the energy efficiency of a house.

How Closed Doors Affect Energy Efficiency

When air is forced out of a room under pressure, an equal amount needs to be drawn so as to replace the expelled draught. Depending on the number of closed doors, the rate of entry of hot or cold outside air could go up by anything between 300% and 900%. This raises utility bills, decreases comfort and brings in a host of health problems.
Since fluids seek the path of least resistance, the largest, straightest and smoothest holes offer the best pathways. Such include the water heater flue, chimney and furnace flue. This reverse flow of air brings in outdoor pollutants and humidity. The only noticeable symptom of this effect would be smoke being pumped back into the house.
Typically, indoor humidity will be at a level that’s more than 60%. Other telltale signs include streaks around the bedroom doors. There are charts that enable homeowners calculate the amount of air flowing into the building, which would be helpful. In some cases, the house could be drawing in about 1000 cubic feet of air per minute when all doors are closed.


Such issues can be tackled by relieving the pressure in the bedrooms. This stops the carbon monoxide sensor from going off. The indoor humidity also plummets to an acceptable level, which creates conditions that are unfavorable for mold growth. Of course, any mold that’s already grown would need to be cleaned up.

One can also undercut the door by a few inches to allow the escape of air. However, some homeowners would find this unacceptable. As such, a return duct that goes back to the AC unit in each room can be installed to provide the necessary pathway. It can however be very expensive.

A cheaper solution would be the installation of transfer grilles or jump ducts to allow air movement between rooms. These give air a path back to the system which is always open. However, they don’t transfer sounds and cannot be seen through. This can be installed by the homeowner if they’re equipped with sufficient DIY skills or by a competent HVAC contractor. Follow our blog for more great HVAC information

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