Air dampers are metal valves or plates that control the amount of heat or cool air that is distributed within your home or building ductwork. When used along with your HVAC (heating, ventilation, and air conditioning) system’s thermostat, shutting off or limiting the amount of heated or cooled air in certain rooms or zones at certain times of the year can help conserve energy, cut down on costs, and make your house or work environment much more comfortable.
There are two main types of HVAC dampers.
Most buildings have manual dampers, which feature simple levers that open or close the valves or plates. This stops the flow of air through one section of ductwork, pushing more warm or cool air to other sections.
Automatic dampers function the same way as their manual counterparts, but are powered by small motors that open or close the valves via remote control. Some automatic dampers are even programmed to modify their positions based on the season or sudden changes in temperature.
If your house or building features manual dampers, you might not be aware of the difference it can make to adjust them when the seasons change. In fact, you might not even know where they are located. To help you take advantage of the benefits of adjusting your dampers, here is a quick step-by-step guide.
Step 1: Find your dampers.
In most homes, finding the dampers should be simple. Go to your basement or utility room and locate your furnace. The dampers should be within a few feet of the main ductwork. They are usually attached to the furnace and feature two pipes with metal levers attached by a wingnut.
Step 2: Test each one.
If your dampers aren’t already labeled by a previous home owner, you’re going to have to determine where they lead to yourself. You can follow the ducts coming from each of the dampers along the wall to get a rough idea. Then, open up all of the vents throughout your house. See if you can find a friend or family member to stand under the vent at the other end of the ductwork that extends from one of the dampers. Turn on the blower on your furnace by setting it to fan mode or by turning on the heat or air conditioning and close one of the dampers by sliding it until it is in a vertical position.
If you found someone to stand under the vents at the other end of the ductwork, have them report back on the status of the air flow. (Or, if you’re alone you’ll have to head over there yourself.) If the vents in that area have little to no air blowing out, you’ve closed the damper that controls the air to that part of the building. Once identified, it’s a good idea to label the duct by writing in marker the room controlled by that damper. Then, go through the same exercise with the second damper.
Step 3: Adjust for the seasons.
Once you’ve pinpointed the location of the air flow, you can control your dampers based on where you want them to flow and when. Since warm air rises and cool air flows downwards, you’ll want to follow this guide:
- Close the damper to the upstairs during cold weather months. This will force the heat downstairs to keep the lower levels warmer. Since warm air rises, it will ultimately make its way upstairs to keep those rooms comfortable.
- Close the damper to the downstairs and basement during warm weather months. This will force the air-conditioning to the upper level, maximizing the cooling effect in the rooms that typically get hottest in the summer. The cool air will still flow downward to keep the ground floor and basement levels from getting too hot.
4. Monitor over time.
Of course, comfortable temperatures have a lot to do with personal preference, so once you’ve established a system for controlling your dampers, monitor the results over time. It might take a few days or weeks to truly zero in on the perfect balance. In some cases, you might want to consider closing dampers part-way versus closing them completely to further moderate the air flow.
Another way to fine-tune the operation of your HVAC system is to open and close the vents in certain rooms or zones, following the same approach as described above for the dampers.
5. Switch the dampers back every season!
Adjusting your dampers to maximize air flow will be a short-lived success if you fail to remember to switch them back and forth each season. Setting an alarm on your mobile device or marking dates on a calendar or near the furnace where you change the air filters are all good ways to remind yourself to switch the dampers every season. Remember, flipping the level vertically up and down will close the damper, and moving them across horizontally will open them and let the air flow through.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.