Closing vents in unused rooms is a common strategy for reducing energy costs in homes with central heating and cooling systems. The logic seems straightforward: if you shut off airflow to unused rooms, the heating and cooling system won’t have to work as hard to maintain the temperature in occupied rooms. But does this strategy really save money and energy? The answer depends on several factors.
The theory behind closing vents
Central heating and air conditioning systems are designed to maintain consistent temperatures throughout the home by pumping warmed or cooled air through ductwork to vents in each room. When all the vents are open, the system has to work harder to maintain the target temperature, using more energy. By closing vents, you restrict airflow to unused rooms so the system only needs to keep occupied rooms at the desired temp. With less air to heat or cool, the system shouldn’t have to run as often, using less energy overall. That’s the theory behind closing vents.
Potential problems with closing vents
In practice, closing too many vents can cause problems including:
- It can prevent proper air circulation and ventilation.
- The system may cycle on and off more frequently as it struggles to maintain temperature.
- Air pressure throughout the ductwork becomes imbalanced.
- The system works harder trying to push air through smaller openings.
- Unused rooms can become too hot or cold if unheated/uncooled.
These issues can put more strain on the HVAC system, leading to premature system failure or higher energy costs over time. For closing vents to be effective, it must be done judiciously.
Guidelines for closing vents
Here are some guidelines from HVAC experts on how to properly close vents to maximize energy savings:
- Never close more than 15-20% of the vents. This maintains proper air circulation.
- Only close 1-2 vents per closed room. Avoid closing all vents in a room.
- Close vents gradually, 1 at a time, checking the impact on room temps.
- Don’t close vents in kitchens, baths or other humidity-prone rooms.
- In a two-story home, don’t close all upstairs or downstairs vents.
- Make sure there’s adequate return-air flow to the HVAC system.
- Adjust vents seasonally as rooms are used differently in summer vs. winter.
Following these best practices prevents problems and ensures that closing vents has the desired effect of reducing energy consumption.
How much money can closing vents save?
The energy savings from strategic vent closing will vary based on factors like:
- House/ductwork design and layout
- HVAC system size and efficiency rating
- Number of vents closed
- Climate and seasonal weather differences
- Electricity costs in your area
Studies suggest closing vents can reduce HVAC runtime by 10-30%. For the average 2,500 square foot home, that could mean potential savings of 5-15% on annual cooling and heating bills, or $75-$225 per year. Larger homes and more extreme climates would see bigger savings by closing vents.
Additional ways to maximize energy savings
While closing vents can help cut costs, it’s most effective when combined with other HVAC optimization strategies like:
- Get regular maintenance and tune-ups for your HVAC system.
- Upgrade to a newer, more efficient HVAC model.
- Ensure ductwork is properly sealed to minimize leaks.
- Change filters monthly.
- Install a programmable thermostat.
- Add insulation in attics and unfinished spaces.
- Seal cracks, gaps and drafts around doors and windows.
Taking a whole-house approach to increasing efficiency provides greater energy and cost savings than closing vents alone. However, strategic vent closing remains a simple, free way to reduce energy waste in unused rooms.
Conclusion
Closing vents can be an effective strategy for reducing heating and cooling costs, provided it’s done properly. While the energy savings may seem modest, every little bit counts when it comes to lowering energy bills. Combined with other optimization techniques, selectively closing vents in unused rooms can be a worthwhile part of a whole-house energy efficiency plan.