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Reznor UDX 45,000 BTU Natural Gas Unit Heater

Reznor UDX 45,000 BTU Natural Gas Unit Heater
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Customer reviews
Rating:
4.9 out of 5
4.9 out of 5 View All 57  Reviews Add Your Review
Out of stock
By

Reznor

Out of stock
Model

UDX-45

ID

55750

3 Questions Answered

DISCONTINUED

The Reznor UDX-45 has been discontinued in favor of the UDXC-45.

Reznor model UDX gas-fired unit heaters are great for space heating applications. These units are power vented to eliminate heat losses up the flue pipe. Each heater features a two-tone black and white powder coated, scratch-resistant paint scheme and has clean rounded corners and edges with no visible screws or fasteners. For air circulation, the UDX series utilize an axial propellor fan.

Standard Features

  • 83% AFUE Efficiency
  • TCORE2 Titanium-Stabilized Aluminized Steel Heat Exchanger
  • Multi-Try Direct Spark Ignition with Time Lockout
  • Low Noise Operation with Vibration-Isolated Fan and Venter Motors
  • Status-Indicating LED Light
  • 7-Segment Display Board for Simple Troubleshooting
  • Optional Integrated Downturn Nozzle and Integrated Vertical Louvers
  • 2- and 4-Point Suspension Options
  • External Gas Connection for Ease of Maintenance and Installation
  • Includes 3 Horizontal Louvers
  • ETL Approved

Product Note

Reznor UDAP is the legacy model of the Reznor UDX

More Information
Reznor UDX 45,000 BTU Natural Gas Unit Heater
FeatureSpec
SKUUDX-45
Weight (in lbs)68
Brand/ManufacturerReznor
ReplacesUDX-45
UPC663132524846
Additional InformationAir Throw: 40 Feet
Furnace Efficiency / AFUE 80-85%
Heating BTU45,000 BTU
Maximum CFM629
Decibel Level (dBA)40
Flue Outlet4"
Watt155 Watts
Efficiency83%
SEER2 (Efficiency)22.3
Electrical115 Volt 1 Phase 60 Hertz
Amperage Requirement2.4 Amps
Connection1/2" NG/LP Connection to Gas Valve
Fuel TypeNatural Gas
Height13 3/4"
Width27"
Depth29 3/4"
Warranty9 Year Heat Exchanger, Burner, and Flue Collection Box Assembly; 4 Year All Electrical and Mechanical Components
Resources You will need Adobe® Acrobat® Reader to view PDF documents.
Safety InformationPROPOSITION 65 WARNING
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Customers Say

Across multiple installations, Reznor unit heaters ranging from 45,000 to 150,000 BTU heat shops and garages quickly and quietly, with reported results such as raising a 950 sq ft garage from 35°F to 70°F in 15–20 minutes, heating a 60x40x16 space from 58°F to 70°F in 35 minutes, and maintaining 60°F in -11°F weather in a 35,000 cubic foot shop. Installation is frequently described as straightforward—even when replacing older Reznor units lasting nearly 20 years—with some minor issues noted such as an incorrect conversion kit promptly corrected and an isolated delivery concern.

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Top reviews
  1. Reznor UDX 60K
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    The unit was packaged well, and the installation was straightforward. It’s heated my workshop in Northern Michigan for three seasons now, and it’s been flawless.

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  2. UDX200
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    Great looking heaters, and performs wells. great service.

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  3. Great support easy transaction
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    Great support and quality product will buy fromagain

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  4. Reznor 60K BTU
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    HVAC Direct delivered on time and unit was incredibly packaged for freight. The unit itself is performing quite well in an uninsulated garage. Keeps everything from freezing. I could not be happier with this purchase and my purchase experience. I will definitely purchase from HVAC Direct when its time to heat my 30x40 barn.

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  5. Outstanding product
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    Got a 46x60 shop with 16ft ceilings the reznor 150,000 btu heats it up fast runs quiet totally surprised how this unit performs

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  6. Fast delivery, great price, excellent packaging with zero damage. Easy to install.
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    Ordered to replace an old UDAP 45. Basically the same but taller. Fit fine as a hanging unit in the garage. Quieter and warmer output than the old one. Pretty much just unhooked the old one, unmounted it and mounted the new one with the same bolts, reattached connections with a slight modification to the venting. Free shipping and it still got here in less than a week. Overall, great experience with HVACDirect and the price was the lowest I could find.

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  7. Great heater
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    Easy installation, quiet and works very well!

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  8. Great purchase
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    We just installed this unit today and it heated my shop up from 58degs. To 70degs. In 35 minutes. The shop is 60x40x16 high.

    Review by

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Customer Questions
Would this work for a 3 stall garage?
This heater should work for a 3-car garage. But just to be safe, you should cross-reference with the Quick Sizing Calculator at the bottom of our Sizing Guide (located at the top of our site). If you have any further questions, please call us and we will be happy to assist you.
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Is this a sealed combustion heater?
Please reference our Sizing Guide that will allow you to know exactly what kind of unit you'll be needing as there are many determining factors such as insulation quality, location, etc... If you have any further questions please feel free to give us a call! Thanks.
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Can this heater be used to heat a home?
These heaters can be used in a garage, but they are not approved for use in indoor living spaces. If you have any further questions, please feel free to give us a call! Thanks.
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Did you find what you were looking for?
5 Best Garage and Shop Heaters
When you need dependable heat in your garage or workshop, only the best will do. Our 2025 picks spotlight top-performing heaters across key categories. For overall reliability and value, the Modine Hot Dawg HD30 stands out—its propane-fired 30,000 BTU output delivers quiet, consistent warmth while fitting in tight spaces and backed by a 10-year warranty on vital components. If electric is your preference, the Reznor EGW‑5 offers instant, clean heat in a compact design that installs quickly and features built-in thermostat control.
May 22, 2022
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