Closing air vents in an attempt to save money on energy bills can paradoxically lead to more expensive problems, according to HVAC experts. Professionals consistently encounter homeowners who cover or close vents in unused rooms, believing this will reduce cooling costs. However, this practice can cause significant damage to heating, ventilation, and air conditioning (HVAC) systems and result in higher utility expenses.
HVAC systems are designed to circulate a specific volume of air throughout all vents in a home. When a vent is closed, the air has nowhere to go, leading to pressure buildup within the system. This pressure can strain ductwork, increase energy consumption, and potentially redirect air away from occupied living spaces.
Randy Huckstadt, a licensed HVAC contractor with JustAnswer, explained that closing vents can create larger issues than the homeowner intends to solve, often negating any perceived savings and incurring service call fees. He also noted other common homeowner mistakes, such as neglecting regular air filter changes, failing to perform routine maintenance on HVAC units, and using the outdoor unit for purposes like picnic tables or workbenches.
Many homeowners also mistakenly assume that if a house feels too warm, the cooling equipment must be malfunctioning. Anthony Ferrara, owner of Dang It’s Hot!, an air conditioning company in South Florida, points out that the AC unit is only one component of a home's cooling efficiency. Factors like attic insulation and ventilation, window and door integrity, sun exposure, ductwork condition, air leakage, ceiling height, and even the use of blinds or curtains can significantly impact a home's cooling load.
During periods of extreme heat, it is common for HVAC systems to run longer cycles. A home's temperature may rise a few degrees even if the equipment is operating correctly. Ferrara advises homeowners to investigate potential issues only if their home suddenly fails to maintain its usual temperature under similar outdoor conditions. In extreme weather, he suggests evaluating the entire home environment and the conditions the AC is working against, rather than solely focusing on the thermostat reading.
To optimize energy efficiency and reduce service calls, experts recommend evaluating the home's environment. For example, placing heat-generating items like lamps, televisions, or laptops directly beneath a thermostat, or allowing direct sunlight to hit it, can create a localized 'fake zone' of heat. This can trick the thermostat into believing the room is hotter than it is, causing the AC to run extended cycles unnecessarily, even when other parts of the house are already at a comfortable temperature.