Buyers Guide & Information

Best HVAC Zone Dampers For AC Duct Systems

We have reviewed the best HVAC zone dampers for controlling your AC system.

If you are looking for better home climate control than your central AC currently offers, you may hear about HVAC zone dampers. A zone damper is controlling multiple areas of the home or space with a single HVAC unit.

This article will examine the advantages and disadvantages of installing HVAC zone dampers and offer you things to consider before you buy. We will also show you the best HVAC zone dampers for AC duct systems so that you can choose the right type for your situation.

Top of the Range

SmartZone-4X Control
SmartZone-4X Control

Our Top Choice


Value For Money


Understanding HVAC Zoning & Zone Dampers

HVAC zoning is a process of cooling and heating different areas using different temperature settings. For instance, you can have your home set up as a multi-zoned environment where the master bedroom is set to a different temperature than the living room or kitchen.

Each zone is controlled by its own thermostat, and in the past, required a separate HVAC system. With zone dampers, you can have multiple zones in your home while using only a single HVAC system. The system still uses multiple thermostats, which control heating and cooling form the system through dampers installed in the ductwork.

When a room needs more air to raise or lower the temperature, the damper to that zone is opened. If the temperature is reached in zone one but not zone two, the HVAC system continues to run, but the dampers close to keep the temperature in zone one while zone two continues to cool off.

Disadvantages to HVAC Zoning

For the most part, HVAC zoning is a great idea and a huge upgrade to your current system. It improves efficiency and helps to lower your monthly energy bills. However, there are a few downsides you need to be aware of.

First, zoning can be an expensive initial investment. Home Advisor estimates that conversion or replacement to a dual-zone system can cost between $2,000 and $15,000. The price, of course, depends on the number of zones in total, equipment needed, labor costs in your region, and if existing HVAC parts can be used or need to be replaced.

Second, if your system isn’t designed correctly, all of that efficiency can go out the window. In fact, with an improperly designed and installed system, your monthly bills can increase.

Assuming you have the system designed and installed professionally, and you decide to invest in the upfront costs and fees, the system will pay for itself through your annual savings in energy bills and utilities.

HVAC Zone Dampers Compared

ModelTypeSizesNumber of ZonesPrice
SmartZone 2XController Kit10.5 x 5 x 1.9 inches2Check Price
SmartZone 4X
Controller Kit11.8 x 6.5 x 2 inches4Check Price
SmartZone 2LController Kit11.7 x 6.4 x 2.2 inches2Check Price
Smartzone Round Damper
Damper Only6, 8, 9, 10, 16 inches1Check Price
Fantech 9800012
RSK-10 Backdraft
Damper Only4, 5, 6, 8, 10, 12, 14, 16 inches1Check Price
Damper Only6 inch1Check Price

Choosing a High Quality HVAC Zone Damper

Below we offer you a brief buyer’s guide. With this section, you will have a better understanding of what to look for when planning and pricing your new multi-zone system.

Compatible Zone Control Panel

Zone control panels are the computer boards responsible for taking the information from the thermostats and sensors to control the airflow. In most cases, you only need a single control panel for the entire system. If you still run multiple HVAC systems or have more zones than the control panel can be wired for, then you will need a secondary control panel.

Control panels are hardwired to the control systems and dampers. However, the thermostats and some sensors van be wireless—more on those, below.


All HVAC zoned systems will come with thermostats. You can install these to work flawlessly with your system, and everything will be just fine. However, the included thermostats may not be the best option for your particular set up.

Each zone requires it’s own control system and thermostat. There are other options, though. You aren’t limited to the thermostats that ship with your new HVAC equipment. Some brands make thermostats capable of controlling multiple zones from a single interface.

These thermostats can also be wireless if you want that freedom. The choice is yours, but your cost will vary depending on your selections.

Duct Size

One of the most important things to know is the size and distance of your ducts. If this is a retrofit installation, you may require more dampers that you would if it is a new install. However, you need to know what size your main branches are, as well as how many smaller branches exist.

Many systems will only use a damper in the main ducting. However, for more precision control, you may want to install more dampers in the smaller service branches of the ductwork.

Damper Size

There are many different sized dampers to choose from as well. Some are designed to be “full operation” only. This means they will either open or close fully. Modulated dampers will work to open or close to various widths to better control airflow and cooling capabilities in the zones they control.

Modulated dampers are more expensive, of course, but will make the system even more efficient. Along with the size of your ductwork, you need to purchase dampers that match the size of your ducts so the system works properly.

Airflow Rate

The airflow rate is measured in cubic feet per minute (CFM). This measurement tells you how much air is being moved in a particular space, or the capacity of a system. When it comes to zoned systems, the CFM will generally have two measurements.

The first is total CFM. Total CFM gives you an idea of how much air can be moved, in total, by the system. Assuming there are no dampers closed, this is the overall capacity of the system.

You also have the Zone CFM. This is the reading or capacity, per zone, that the system can move. The higher the numbers, the more air is moved, resulting in faster cooling or heating.

However, if your system is rated too high for the space, you can lose some of the efficiency a zoned system offers. Likewise, if you don’t have a high enough CFM, the system will run longer, costing you more in energy consumption.


The material of your ductwork will also come into play. The most common type is galvanized steel or aluminum. However, there are about a dozen different materials used for HVAC ductwork. Other options are fiberboard, pre-insulated polyurethane, fiberglass, and even PVC.

Some dampers will not work properly or be able to seal some materials. Not only do you need to know what type of ducting material you have (or will install), but you also need to know the limitations of the dampers based on the chosen materials.


Another initial cost factor is room sensors. Depending on the control board and thermostat types, you may be required to install room sensors. Sensors will report to the control board and the thermostat the actual temperature in the room.

In a traditional system, the temperature is read at the thermostat only. This means that you can set the temperature to 75 degrees (F), and the system will shut off when the thermostat reads 75. Even if the bedroom is only 70 degrees, the system won’t run.

Sensors help prevent this by reporting the actual temperature across the zone. While they aren’t required, they are a considerable efficiency benefit to your new system.


Finally, you will want to look at the warranty offered by the system you select. The warranty should cover the dampers, thermostats, and sensors. The term will depend on other factors as well, such as installation type (DIY or professional), type of system the zoned set up is added to, or if it is a new install versus a retrofit.

You will also need to perform certain steps to enact the warranty in most cases. This can be as simple as registering your product online, or you may need to supply proof of purchase; the proof is professional installation or other factors. Make sure you read all of the fine print before you buy.

6 Best HVAC Zone Dampers Reviewed

Below we offer you the 6 best HVAC zone dampers and controllers reviewed and compared for your convenience. Take a look at the options and find out which one is best for you.

1. SmartZone-2X

Specification Summary
TypeController Kit
Sizes10.5 x 5 x 1.9 inches
Number of Zones2

The SmartZone-2x is a dual-zone controller designed for universal integration. This controller is ideal for new installs, retrofits, upgrades, and replacement. There isn’t anything you can’t do, theoretically.

The controller is universal for all 24v dampers. It runs on a dedicated 24v line with bright LEDs to let you know f any connection failures, status, and troubleshooting. The controller will power two dampers per board but can be paired to hold up to 20 dampers for a single HVAC system.

You don’t have to worry if your system is compatible. It is. This control board will work with any electrical, gas, dual-fuel, single-stage, multi-stage, or heat pump. It also comes with a temperature probe to replace any current system that may require one to operate.

Your existing thermostat will also work, and if you choose to upgrade that, the new one will work as well, including smart thermostats or wireless programmable thermostats.

With the SmartZone-2x you can take full control of your new multi-zone HVAC system, dampers and thermostats without having to worry about compatibility or functionality. The board also sports a 5-year warranty to help you keep peace of mind while you make your system more efficient.


  • Economy mode, allows calls from zone 1 only, saving money while you are away.
  • Second stage lockout prevents multiple calls when not needed.
  • Truly universal design.
  • Efficiency in up and downstaging


  • Doesn’t come with any other equipment or pieces (dampers, thermostats, etc.)
  • More expensive than some other models with similar specs

2. SmartZone-4X Control

Specification Summary
TypeController Kit
Sizes11.8 x 6.5 x 2 inches
Number of Zones4 zones

Ecojoy is back with the SmartXone-4x control board. Just like the top pick, this is a universal board designed for all types of installations. Whether you are performing a new multi-zone install or upgrading from a single-zone system, the SmartZone-4x is worth a look.

This control board will power and monitor four different dampers. You can use virtually any damper as well, as long as it is 24v, the damper will work. This includes 2- and 3-wires connections.

When it comes to thermostats, the 4x is compatible will all major brands, including Honeywell, Nest, Ecobee, and even standard, wired, thermostats if needed. If you need to add more than 4 dampers, this control board allows you to do just that.

Using the SmartLink BUS, you can connect up to 5 4x control boards together for a total of 20 dampers. If you need a different number, you can combine the SmartZone-2x control board (our top pick) into the BUS controller, too, to get any number between 2 and 20 dampers installed in your system.

The control board also offers simple installation and set up, you don’t need screws, and all wires are push-tight locked without having to use set-screws.

The 4x has the same 5-year warranty as the 2x does. The standard warranty restraints apply. You don’t need to have the control board professionally installed for the warranty, but it won’t cover if you wire it wrong, connect the power wrong, or otherwise have problems with abnormal use or abuse.


  • Use economy mode to setback all zones with one switch.
  • Use with any system, set up, or thermostat.
  • Self-stages up and down to be as efficient as possible.
  • Uses fresh air control without separate purchases.


  • Requires multiple boards for more than 4 dampers.

3. SmartZone-2L

Specification Summary
TypeController Kit
Sizes11.7 x 6.4 x 2.2 inches
Number of Zones2

The Ecojoy SmartZone-2L is a great control board kit for simple 2-zone systems. With the 2nd stage lockout, you can eliminate the need for a bypass duct that can hold moisture and grow mold. The board is more affordable than the X line (our top picks) but lacks the ability to pair with other boards for adding more dampers.

If you have a single system with two zones, you will love the easy installation and set up of this control board. It features a push-button display to cycle through troubleshooting, modes, and system statuses.

If you need more than two dampers, you will need to purchase and install another control board, but they won’t link together. It is advised to go with the better-equipped 2X of 4X boards instead. However, the 2L does allow you to use any type of system, including gas, electric, or dual-fuel. You can also connect 2 or 3-wire dampers as long as they are 24v models.

This controller kit comes with easy to follow installation instructions that will have you heating and cooling your zones in no time. If you do have any trouble, the people at Ecojoy are more than happy to help you. A simple phone call is all it takes to get the assistance you need.

We can promise that you won’t need the phone call, though. This control board is almost fool-proof, and if you can push a wire into a connection hole, you can install this board. Like all Ecojoy products, the warranty covers normal use and wear and tear for 5-years.

You should register your product and maintain proof of purchase during the warranty period, though. It will make a claims process much easier if you do.


  • Includes temperature probe
  • Ideal for replacement of higher-cost controllers.
  • Digital readout for zones, modes and more


  • Doesn’t offer bridging for extra damper support.
  • Not ideal for complex systems

4. Smartzone Round Zone Damper

Specification Summary
TypeDamper Only
Sizes6, 8, 9, 10, 16 (inches)
Number of Zones1
Warranty5-year replacement

For the best actuated damper, SmartZone has you covered. The 8-inch model is one of the most popular motorized power dampers on the market, though they offer 5 different diameters to accommodate almost any installation.

You will find the round dampers in 6, 8, 9, 10, and 16 inches, which should fit almost any commercial and residential application. The rugged design is backed by a 5-year warranty, too, but you won’t need it. The galvanized steel construction ill hold up to temperature swings all year round and will help you prevent drafts, air leaks, and other efficiency loss aspects of a conventional HVAC system.

The high torque Bellimo motor only requires 1.5 watts to open or close the blades, which seal off virtually 100% of all airflow when closed. You can use these dampers to create zones or to prevent heat from escaping your vents in the winter.

They will work with any 24v control board that operates with 3-wire mounting. Not only is this damper efficient, but it will save on energy consumption, too. The full-seal gasket on the blade ensures minimal leaking and requires 18-in pounds of torque to open. It won’t move in a breeze or draft.

Once installed, you will also notice there is a quieter operation of your HVAC system as the damper also works to help reduce noise from your fan, attic vent, or other zones. If you want the best round zone damper for your multi-zone HVAC system, the SmartZone for Ecojoy is your choice.


  • Multiple sizes for various applications
  • Bellimo motor only draws 1.5 watts
  • Made in the USA
  • Commercial grade galvanized steel construction


  • Can be difficult to install
  • Need personal protection equipment to prevent cuts.

5. Fantech 9800012 RSK-10 Backdraft Damper

Specification Summary
TypeDamper Only
Sizes4, 5, 6, 8, 10, 12, 14, 16 (inches)
Number of Zones1

If you are looking for a simple design in your backdraft damper, the Fantech models will give you excellent airflow protection and require little modification to install.

The dampers are made from a galvanized steel collar and aluminum blade. The backdraft damper requires at least 165 CFM to open, and the spring-loaded closure is light but functional. These dampers won’t slam shut, unlike other models which can cause damage or shorten their life expectancy.

Instead, you get a solid design, rugged construction, and paired with a Fantech fan, you will have a worry-free operation for years.

The downside here is that there isn’t a warranty. Since there are no electrical parts, there isn’t much to warranty. The springs will wear out over time, but this is normal wear and tear and wouldn’t be covered anyway. However, if you purchase through Amazon, the dampers are returnable if something is wrong.

When installing, you should be cautious of the blade direction. You will want to install these dampers in a vertical blade orientation instead of horizontal. This will help ensure a proper close and more effortless opening.

You have many sizes to choose from, including 1-inch variances from 4 to 8 inches and 2-inch variance from 10 to 16 inches. With 8 sizes to choose from, your perfect fit is just one order away.


  • Simple operation with moderate CMF required to open
  • Cost-effective damper to control loss of heat or cold air.
  • Simple installation can be done in about an hour.


  • Return through Amazon only
  • Needs to be installed in a vertical alignment.

6. Speedi-Collar SC-06D

Specification Summary
TypeDamper Only
Sizes6 inch
Number of Zones1

If you are in a hurry, the Speedi-Collar balance damper is made to install in a matter of minutes. The construction is solid, too. Using UV-resistant resin, you can’t dent the collar or blade, and neither will succumb to rust.

The best part, though, is you don’t need to spend hours in the attic trying to get them installed. With the Speedi-zip system, the collar will attach to the ducting end with a few tugs, and you can have the entire project completed in minutes.

Of course, there are a few downsides. Mainly because of the machine-molded resin, there may be burrs or edges that need to be trimmed before installing. Also, the plastic-on-plastic of the blade and collar mean you won’t get a 100% non-movement. Eventually, you will need to readjust the balance.

The balance is easy to set and will hold for quite a while without needing any adjustments. As long as you aren’t expecting to have 100% maintenance-free settings, you won’t be disappointed.

You also don’t need to put your hand and arms in harm’s way, with sharp edges or reaching inside ducting to install. Initially designed for a temporary fix, the construction and production process has enabled you to use the Speedi-Collar in a more permanent setting.

While you won’t get a warranty, you will get an affordable, simple installation and noticeable energy savings from a 10-minute project that could end up saving you hundreds.


  • 6-position balance settings
  • 10-minute install
  • Can be used as a temporary fix or permanent solution.


  • Won’t last as long as other models
  • May need to be trimmed or cut before installation.

Types of Dampers in HVAC Systems

Control Damper

Control dampers are installed in the ductwork along the airflow lines. Using actuators, these dampers will be fully open to allow air to flow by, or fully closed, to prevent any airflow from getting past.

Balancing Damper

Balancing dampers are installed much the same as control dampers. However, they are set in place once the correct airflow and pressure is observed. Once set, they do not open or close any further.

If future adjustments are needed, the balance dampers will require adjustment before being set again.

Backdraft Damper

Backdraft dampers are almost identical to control dampers, with the exception that their blades only open in one direction. These dampers prevent airflow from moving in both directions and will work without actuators.

Instead, they will have weighted bars on the blades to keep them closed when no air pressure is present and only open when the air is moving.

Multi-Zone Damper

Multi-zone dampers are using in buildings with many rooms, such as a school, office space, or multi-family dwelling. Each damper is connected to an actuator and control board and operate independently of each other.

Industrial Damper

Industrial dampers, as the name implies, are large, rugged dampers. They are designed from steel and welded together to aid in durability. Not only can they withstand extreme temperatures, but they also handle a lot of airflow.

You will find these dampers in industrial zone businesses, warehouses, and factories.

Zone Damper Installation

Zone damper installation will vary depending on the type of dampers and system you have (or are installing). Some dampers require installation into the ductwork, while more straightforward methods are installed at the registers in each room.

Some systems will only need a damper installed in each major branch of the ductwork. Likewise, there will be installs with more than two dozen dampers. For a basic installation of a register located wireless damper, check out this video from This Old House to see how a simple installation on an existing system can be.

People Also Ask (FAQs)

What size dampers do I need?

The needed size of your dampers is determined by the size and style of your ductwork. It also requires calculation of the square footage of the zone itself. Most dampers range in size from 2 inches to about 2-feet. Usually, they will be produced in 1-inch increments so you can get the perfect size for your needs.

Can I add zones to my existing HVAC system?

Yes, you can add zones by installing ducted dampers to your existing system. However, there are cautions. Single stage systems only operate at full capacity. To properly zone your system, you will also need to install a bypass duct. There is substantial debate on the benefits or negatives to a bypass duct, including extra wear on the system and mold growth.

Do all HVAC systems have dampers?

Most HVAC systems have dampers, but not every single one of them. In most cases, you will find butterfly dampers installed within a few feet of the main trunk in your system. There will be an adjustable handle on the outside of the duct for you to adjust the damper if needed.

When do I need to have a zone damper installed?

The best time to have zone dampers installed is during a fresh install or a retrofit. If you are hoping to add zones by simply adding dampers, it will be more cost-effective and efficient to wait until it is time to replace your HVAC system.

What are the benefits of zoned HVAC systems?

The biggest advantage is significant efficiency. By zoning your home, you can control where the air goes and how long it needs to run, which can save energy by preventing unnecessary heating or cooling in rooms that aren’t occupied.

How do I open and close my HVAC damper?

This will depend on the type of damper you have installed. Some will be automatic based on the thermostat settings. Others are wireless, controlled by a control board or a mobile app. Other dampers use actuators or manual handles to adjust.

How do I test my HVAC damper?

The only way to test your dampers it to check the airflow at the registers. If you have manual dampers, close them and turn the system on. For automatic dampers, program them to close the zone then start the system. If you can feel air flowing at the register in the zone with closed dampers, the damper is bad.


Choosing the right multi-zone system for your HVAC system can be a challenge. There a lot of options, sizes, and styles to choose from. When you are in doubt, we highly recommend out top pick. The SmartZone-2X is universally compatible with any system. Single and multi-stage systems, any 24v damper, wireless or wired thermostats, and gas, electric, or multi-fueled systems.