What are HVAC zones?

mature woman in blue shirt programming hvac zones on smart thermostat

Within urban development circles, municipalities often classify different areas as zones. Those can be commercial, residential, mixed-use, and so on. Zoning simply means that all structures within that area will fall into the same type of category. Are HVAC zones the same thing? Let’s look at the term closer and how it might be the solution for your home or business.

First, what are HVAC zones?
Before we can unpack what HVAC zones are, we first need to understand why they are important. First, picture a handheld, old-school mercury thermometer. The thermometer reacts to whatever temperature it is on the tip, raising or lowering the mercury level as appropriate.

Let’s pretend it’s 95 degrees in your home — far too hot for comfort. Now, we’re going to have you imagine an ice-cold glass of water — literally filled to the top with ice cubes. Place that thermometer in the ice water. The mercury level will drop relative to the temperature of the water. 

Despite this, the temperature in your sauna-like living room is still 95 degrees. In other words, the thermometer doesn’t know it’s warmer elsewhere; it only knows the water temperature.

That’s why you need HVAC zones
The metaphor for the thermometer is your wall-mounted thermostat that controls your HVAC system. Usually, these are on the first floor, typically centrally located within a living or dining room. When a single thermostat controls a home, we call this an “unzoned” home. It can be 125 degrees upstairs, but if the thermostat is set to turn off at 75 degrees, once the air temperature near the thermostat reaches 75 the system will stop running.

This is why older homes often have hot and cold spots: they’re unzoned, which means that once the thermostat reaches the desired temperature that’s it. No more cold (or warm) air.

HVAC zones mitigate this issue by adjusting the operation of your HVAC system(s) to compensate.

Types of HVAC zoning
Just as there are multiple types of urban development zones, there are also several ways that a home can have HVAC zones. The most common are:
• A home with multiple thermostats, often automatically opening and shutting dampeners within your ductwork;
• Homes with multiple HVAC systems, and;
• Multi-trunk setups.

Which style of HVAC zoning system is right for your home is often a matter of working with your HVAC contractor to determine the most effective system. An older home with less square footage would be more likely to benefit from the automatic dampener based system. A larger home will often have multiple HVAC systems.

Is there a manual zoning option?
Yes, though this would technically still be classified as an unzoned home. A manual damper that you install within your main trunk line can be helpful to control the airflow based on seasonal temperature variations. Also, opening and closing vents based on a trial-and-error scenario can help keep your home’s temperature more uniform.

Beehive Heating and Air can help with your HVAC zoning needs
Creating adequate HVAC zones is a matter of planning and often retrofitting existing systems. If you’d like to learn more about how creating HVAC zones can help eliminate hot and cold spots in your home, give us a call at (801) 980-0903 or request a free online quote here.

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