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How HVAC Zoning Works

Will McLeod Community Resources

Your HVAC system is more than just a thermostat. It’s actually several machines doing several different jobs, all coordinated by your thermostat.

The parts of a typical HVAC system

Courtesy of

Your HVAC system probably has a furnace (or heat pump) responsible for creating hot air, an air conditioner for creating cold air, and an air handler (blower fan) for moving that temperature-controlled air around. Your thermostat coordinates these functions.

Thermostats are fairly simple devices. They used to be entirely mechanical and could do their job with a bimetallic strip that would expand in response to changes in temperature. Nowadays, the temperature sensing is electronic, but the function is the same - when a temperature threshold is reached, turn on the furnace or the AC then turn on the blower to move the air through the whole house. However, your thermostat doesn’t know or do anything about the individual temperature differences between rooms. It simply turns on a blower and ventilates the whole house as if every room were the same temperature at the same time.

Back in the old days, if you had a temperature imbalance, or wanted to save energy by only heating the part of the house that you were using, you needed to install a second zone. Zones are simply different areas of your home, each controlled by separate thermostats, though creating multiple zones takes a lot more than adding a second thermostat.

In addition to leveraging a second or third thermostat, zoning works by adding a zone controller and several duct dampers. The thermostats are wired to the zone controller, which manages the distribution of air based on whether one, the other, or all of the thermostats call for hot or cold air. If the thermostats compete–such as one calling for heat and one for AC–the last one to ask wins out.

The zone controller is also responsible for controlling the duct dampers. Dampers are baffles controlled by electric motors that permit or block airflow inside the ductwork. Sounds similar to Smart Vents, we know, but unlike Smart Vents, dampers are invasive, meaning they are installed inside of your ducts, rather than at the supply vents. Yes, this means tearing open your wall/ceiling and then patching/repainting to install every single damper. If a zone is not calling for heat or AC, the baffles are closed. Some zoning systems have pressure bypasses, such as when there are many zones and too much of the airflow might be restricted--but most don’t. Here’s a diagram depicting a typical zoned HVAC system.

Zoned HVACCourtesy of

Zone systems can get the job done if you are living with temperature imbalances. That said, they are technologically stale by several decades yet also quite expensive. The average zoning system costs between $3,000 and $8,000, including the cost of labor to install them. That’s where Smart Vents come in.

Smart Vents take the concept of traditional zoning and bring it to the 21st century. Where traditional zoning systems divide a home into two or three zones based on floors of the home, a Smart Vent System lets you turn each room in your home into independently controlled zones. You’re more likely to be able to identify a room or two in your whole house that you aren’t using or that have temperate imbalances, rather than an entire static group of rooms.

Smart Vents are also connected devices, so they improve over time through "over the air" software enhancements. We’re rolling out all kinds of new features this year that we know you’ll love. Additionally, Smart Vents vary the levels of airflow as opposed to simply being open or closed like most zone dampers. Smart Vents are DIY, meaning you can install them yourself, saving you a lot of cash on the cost of hiring someone to come out and install a traditional zoning system for you. A Smart Vent System is modular and can be built up room by room, costing less than $1,000 for most households.

Here’s a table we put together comparing Smart Vent Systems to traditional HVAC zoning systems:

Smart Vent System Pro HVAC Zoning
Hardware starts at $195 $2,500+
Installation FREE (DIY) $8,500+
App Control          
Auto-balancing (coming soon)
Nest Integration
Room Zoning
Smart Scheduling
HVAC Analytics


With winter fast approaching, now is the perfect time to consider adding zoning to your HVAC system. You’ll have greater control over airflow throughout your home, meaning more comfort and a smaller energy bill every month. Whether you invest in a traditional zoning solution for each floor of your home, or have even more control by creating discrete zones for each room with a Smart Vent System, you’ll be doing yourself and your family an enormous favor by eliminating those troublesome hot and cold spots in your home.

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  • Ken on

    Hi, I have 2 Elgato Room Sensors that sense temp to 100th of a deg. I also have a Honeywell T6 pro Lyric WIFI thermostat, and would like to be able to use these devices as sensors and thermostat with Keen devices. The other devices are all compatible with Apple Home Kit. Can Keen work with these devices or a sub set to enable zoned temperature management ?

    Note: I already have the capability to turn up heat in a room by elgato sensor value to the lyric via home kit…The missing element is vent control…

  • Daniel J Wendell on

    It would be cool if the vent had an Ecobee compatible temp sensor built into it, so I did not have to get Ecobee temp sensors for every room. Although I suspect the vent is not the best location for the sensor as it would fluctuate a lot.

  • Mitchell on

    Juan, in your example the vents would close on the first floor while opening on the second floor, to restrict air flow to the floor that does not currently need it.

  • ALex pEterson on

    Have four story condo. Smart vents make temperature zoning a breeze and saves energy. This concept pays for itself in a short period of energy savings

  • Juan E. Vargas on

    How would smart vents deal with the fact that most A/C systems have single-speed compressors and furnaces that operate under a single on/off switch?

    If, for example, a two-floor house operates with a single-speed compressor and the one and only thermostat in the first floor, how will the smart vent tell the compressor/thermostat to send air to the second floor when that part of the house is warmer? Similarly, how will the smart vent tell the furnace/thermostat to send warm air to the second floor but not to the first? In both cases, the heating/cooling unit simply starts or stops, there is no point in between…

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