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How to Split Heating Zones

December 23, 2022

Oregon Ductless Heroes


Before central air conditioning, people turned radiators on and off in each room to adjust the temperature. Therefore, HVAC zoning has a long history of residential use. But it’s more complicated in central HVAC systems with a network of ducts. They often feature one single zone in which one room or floor can be hotter or colder than another. We will explain how to split heating zones in winter to avoid dealing with uneven temperatures in your home.

Determine the Capacity You Need

Based on the size of your home, an HVAC contractor will determine the capacity, in BTUs or tons, needed. Simply adding dampers to your existing ductwork can increase the air pressure in ducts and strain the system. You’ll need new equipment to fully benefit.

The technician will size a unit based on climate, house orientation to the sun, number of windows, and other variables. Systems can be compared using manufacturer-rated nominal capacity ratings. Meanwhile, actual capacity affected by outdoor temperature and humidity, installation variables, and line-set length is also considered.

Select a Condenser Type

Multi-port condensers have built-in refrigerant ports. With these, multiple connections can be made between the outdoor condenser and indoor air handlers. Independently controlled zones can be created without brazing additional pipe connections. However, this can lead to higher installation expenses, limited capacity, and multiple line sets being run outside.

A branch box typically has a higher capacity and allows a single connection between the outdoor condenser and indoor units. It can supply the appropriate amount of refrigerant to each unit and can be linked to an additional branch box. Doing so can achieve up to eight zones.

A variable-speed condenser is best-suited for splitting heating zones. Traditional systems either run “On” or “Off” or at “Low” or “High” speed. A variable-speed system can increase or decrease capacity in increments to adjust to demand, so static pressure, equipment strain, and temperature variations are less of a concern.

Install Ductwork Dampers

Dampers control the amount of air flowing through the ductwork. They can close off to limit heating in areas that aren’t occupied. The system is designed to adjust capacity accordingly. An HVAC technician is trained and equipped to install these dampers and won’t need to place a bypass duct (which reduces evaporator coil efficiency), as a smaller volume of air will be required.

Select Indoor Units for Your Mini-Split System

In addition to capacity, you want to consider aesthetics, convenience, and your home’s layout when selecting indoor air handlers. A mini-split heating system can use standard wall mount units. Indoor units are also available in recessed ceiling cassettes, suspended ceiling cassettes, concealed ducts, and floor-mounted models.

Choose a Thermostat

No discussion on how to split heating zones is complete without talking about thermostats. There are many types and models to choose from. With a split heating system, you can connect two or more thermostats to a master control panel that opens and closes the dampers. Programmable thermostats are highly compatible with zoned heating systems and can further improve efficiency. A smart thermostat allows you to manage each zone remotely and may monitor efficiency and system usage.

Call a Professional Who Knows How to Split Heating Zones

Splitting HVAC zones is not a project for the average DIYer. It requires planning as well as cutting walls and performing mechanical and electrical work. The installation of zone valves and controls requires a lot of knowledge and skill. Fortunately, an HVAC contractor can determine if setting up heating zones is right for your home and, if so, how to approach sizing and installation. 

Oregon Ductless installs single- and multi-zone as well as whole-house ductless heat pumps. In addition to high-quality installation, we provide professional repair and maintenance services. A 3D Daikin dealer, we provide the most advanced Daikin heat pumps that can connect to up to nine indoor units of different styles and capacities. 

Contact us online or call 503-755-5332 to schedule a consultation and learn about our financing options.


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