Single-Stage Downflow Furnaces - 80% AFUE

Stay cool in warmer climates with downflow furnaces.

If you live in a climate that experiences hot and humid summers paired with mild winters, then a downflow furnace may be the perfect solution for regulating your home’s environment. Specified for attic or upper-level installation, these units push cold air down. Due to this cooling efficiency, you save money all summer long, maintaining a cool temperature throughout your home. Then, when outdoor temperatures drop, Durastar’s downflow furnaces provide dependable warmth and comfort.

When replacing an outdated furnace, talk to your contractor about placement options as well as compatibility with any existing piping systems. And, be sure to conduct a thorough review of both our Core Series and Advanced Series furnaces.




No one stands behind their brand like we do. Durastar offers durable airflow during even the harshest heating and cooling conditions. In addition, our warranty provides maximum coverage for total peace of mind.

Extended warranty options are available for both parts and labor. Talk to your contractor for more information.

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Single-Stage Downflow Furnaces - 80% AFUE Features

  • HVAC equipment products sold to licensed contractors only. Products sold in select areas only, please contact your local branch for availability in your area.
  • Not all Durastar products may be available in all areas currently. See your local Durastar distributor for details.
  • Constant torque ECM motor maintains efficiency across a range of operating speeds for increased energy savings
  • Direct spark ignition system is one of the most dependable ignition systems on the market
  • Aluminized steel constructed heat exchanger provides maximum corrosion resistance and thermal fatigue reliability. It is also removable for improved serviceability
  • Low profile 34" cabinet is ideal for space constrained installations
  • Diagnostics: Industry-first, 7-segment LED for quick & easy service


  • AFUE: 80.00 %
  • BTU: 50000
  • BTU Heat Rating: 40000 Btu/h
  • Blower Type: Direct Drive
  • Communicating: Non-Communicating
  • Condensing: No
  • Configuration: Downflow
  • Energy Star Compliant: No
  • Fan Speeds: 5
  • Flue Size: 4
  • Fuel Type: Natural Gas
  • Height: 34 in
  • Horsepower: 1/2 hp
  • Ignition System: Direct Spark Ignition
  • Length: 28-1/16 in
  • MBH: 50
  • Phase: Single Phase
  • Power Source: Gas
  • Specifications - UL Listed: Yes
  • Stages: Single
  • Style Name: DR80DZAT
  • Tonnage: 3 Ton
  • Type: DR80DZAT0501314SAN
  • Volts: 115V
  • Weight: 85 lb
  • Width: 14 in

DR80DZAT0501314SAN Documents

Frequently Asked questions

Is an air handler or furnace better?

Both Durastar’s furnaces and air handlers offer dependable options for distributing even airflow throughout your home. When selecting between the two, consider your location and climate. For areas with long warm seasons, an air handler will likely be more energy-efficient, however, we recommend discussing your options with a licensed contractor to ensure the best combinations of HVAC products for your home.

What does variable speed mean?

Variable speed air handlers operate at the lowest possible speed to achieve your desired indoor temperature. This results in increased energy efficiency. Variable speed units are also quieter than standard units.

Is a two-stage air handler more efficient than a single-stage air handler?

Yes, when paired with a two-stage outdoor unit, both units will operate on low capacity during milder days, requiring less energy; and switch to full capacity and power when needed.

What is AFUE?

Annual Fuel Utilization Efficiency (AFUE), is a standardized measure of efficiency for how furnaces and boilers convert energy to useable heat.

What is the main difference between a furnace and a heat pump?

Furnaces burn fuel to generate heat whereas a heat pump draws air from outdoors across the condenser coil, either releasing heat to the outdoor air when in cooling mode or absorbing heat from the outdoors, even in the coldest weather in heating mode.

How often should my furnace be serviced?

Durastar recommends your furnace to be serviced at least once a year to ensure it is functioning optimally and providing maximum comfort.

How to talk to your contractor

Learn how to talk the talk with a few of our top tips. We cover important questions to ask your HVAC contractor, common mistakes when buying a new system, and more.

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