• Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300
  • Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300

Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300

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  • Full Interior Kit
  • Since 2009

Reznor UDX 300,000 BTU Natural Gas Unit Heater - NUDX300

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.

Features
  • 83% AFUE Efficiency
  • TCORE2 titanium stabilized aluminized steel heat exchanger
  • Multi-try, direct spark ignition with time lockout
  • Vibration/noise isolated fan and venter motors designed for low noise operation
  • External status indicating LED that blinks if there is a problem that needs service
  • 7-segment display board that shows fault code for quick and easy troubleshooting
  • Optional integrated downturn nozzle and integrated vertical louvers
What our Experts Think
  • Built for serious heating demands
    With 300,000 BTU input, this unit is engineered for large commercial, industrial, or warehouse spaces, delivering powerful and consistent heat output where smaller units fall short.
  • Strong efficiency for its class
    Operating at around 83% AFUE, it strikes a solid balance between fuel efficiency and high-capacity performance, making it a practical choice for long operational hours.
  • Durability you can rely on
    The TCORE2® aluminized steel heat exchanger is designed for longevity under demanding conditions—ideal for environments with heavy-duty usage.
  • Smart diagnostics & easy servicing
    Features like a 7-segment display board and LED diagnostics simplify troubleshooting, reducing downtime and maintenance costs.
  • Quiet, low-vibration operation
    Despite its size, the unit uses vibration-isolated motors and an axial fan to maintain relatively low noise levels—important for workspaces.
  • Efficient heat distribution
    With airflow reaching ~3,800+ CFM and up to 90+ ft air throw, it ensures wide and even heat coverage across large areas.

Q&A

Q1: What size space can the Reznor UDX300 heat?
A: With 300,000 BTU input and ~249,000 BTU output, it’s ideal for large commercial, industrial, or warehouse spaces requiring powerful, consistent heating.

Q2: How efficient is the Reznor UDX300 heater?
A: It offers up to 83% AFUE efficiency, delivering strong heat output while minimizing energy waste.

Q3: What type of fuel does this unit heater use?
A: The NUDX300 operates on natural gas and can be converted to propane with an optional kit.

Q4: Is the Reznor UDX300 suitable for commercial use?
A: Yes, it’s designed for commercial and industrial applications, including workshops, garages, and large facilities.

Q5: What makes the UDX300 durable and reliable?
A: It features a TCORE2 titanium-stabilized aluminized steel heat exchanger, ensuring long-lasting performance and resistance to corrosion.

Q6: Does it operate quietly?
A: Yes, the unit includes a low-noise axial fan with vibration isolation, making it quieter than many comparable heaters.

Q7: Is installation and maintenance easy?
A: The heater includes external gas connections, diagnostic LED indicators, and a simple control board, making installation and troubleshooting straightforward.

Q8: What are the key airflow and performance specs?
A: It delivers up to 3843 CFM airflow with an air throw of ~94 feet, ensuring even heat distribution across large areas.


Maintenance Tips
  • Clean air pathways regularly: Keep fan blades, louvers, and intake areas dust-free to maintain proper airflow and efficiency (≈83% AFUE).
  • Inspect heat exchanger annually: Check for cracks or corrosion to ensure safe combustion and long lifespan of the TCORE2® exchanger.
  • Check gas pressure & ignition system: Verify proper operation of the direct spark ignition and gas connections to prevent misfires or inefficiency.
  • Monitor venting system: Ensure the power vent and flue are clear of obstructions to avoid heat loss and unsafe exhaust buildup.
  • Tighten electrical connections: Periodically inspect wiring, control board, and LED diagnostics for faults or loose connections.
  • Lubricate and inspect motors: Keep fan and venter motors running smoothly to reduce noise and wear.
  • Schedule professional servicing: Annual HVAC servicing helps maintain warranty compliance and peak performance.

  • DIY Install

  • OEM-Inspired Fit

  • Air Bag Friendly

  • 3 Year Warranty

  • Custom Colors

  • Work Gear & Pet Friendly

  • Since 2009

Why Truck Owners Choose Seat Covers Over Reupholstery

Traditional Reupholstery TruckLeather Seat Covers
Upfront Cost

$2500-$4000+

$399-$999

Vehicle Downtime

Days or Weeks

None

Risk Level

Permanent, No Undo

Fully Reversible

Best Use Case

Full Restorations

Restoration or Prevention

Resale Value Impact

High Cost to Recover

High ROI

TruckLeather gives you 90% of the visual and comfort upgrade at a fraction of the cost of reupholstery without giving up your truck.

WHEN YOUR TRUCK DESERVES THE BEST. UPGRADE YOUR TRUCK'S INTERIOR WITH THE INDUSTRY DEFINING TRUCK SEAT COVERS WE HAVE REFINED OVER 15 YEARS.

  • Will these work if my seats are already damaged?

    Yes. TruckLeather seat covers are commonly used to cover cracked, faded, or worn-out truck seats while preventing further deterioration.

  • How do these compare to cheaper seat covers?

    Universal covers focus on price. TruckLeather focuses on fit, durability, and long-term protection.

  • Are these permanent?

    No. They’re fully removable and won’t alter your factory seats.

Slip on leather seat covers
Slip on leather seat covers

Easy At-Home Installation

No special tools. No upholstery shop. No risk.

Our seat covers are designed for DIY installation, with step-by-step instructions and support available if you need it. Most customers complete installation in a few hours.

STEP BY STEP INSTRUCTIONS
Red and Black Custom Leather Seat Covers for Ford F150

Your Truck.Your Style.

Custom orders are our jam. Our custom program makes for a truly bespoke experience leaving only your imagination for the thousands of possibilities. If you're looking for the best truck seat covers then look no further!

Clazzio seat cover

Airbag Safe

Our seat cover construction has a high priority for allowing the OEM seat airbags to properly deploy when needed.

The proprietary thread design allows for the SRS systems to continue to function in a collision situation.

Clazzio Leather Covers

Made for your truck.For life.

Our seat covers are made exactly for your interior setup, perfect every time.

We offer most color setups in stock such as all black and all dark gray, however our custom color program is ready for your creative setups.

FAQ

Learn more about our truck seat covers with the frequently asked questions below.

DIY installation instructions are included for your specific application and takes around 2-3 hours for full interior installation.

The specific application specific instructions provided have step by step photos of how to install your new seat covers as well as tips and tricks. 

If you don't feel comfortable installing the seat covers yourself, then any local upholstery shop should be able to install them no problem.

Some vehicles do require cutting in certain spots like the power seat control panel, but nothing too major.

These leather seat covers are 100% slip on seat covers and do not require removal of your existing seat material.

Yes, our seat covers are fully compatible with factory heated and cooled seats.

Clazzio (our manufacturer) offers a 3 year warranty that is honored on any manufacturer defects.  This does not include normal wear and tear that comes with use on these seat covers.

You will receive the full interior seat cover set which includes bottom cushion covers, top cushion covers, head rest covers, and depending on the vehicle, arm rest covers.  It is a total makeover.

They are made by 11i-USA who manufactures these under the name Clazzio. They operate a large dealer system and we are a top nationwide dealer for them.

It depends if you ordered a custom set or not.


If you ordered a set that is in stock, then it will reach you in approximately 5-6 days via UPS ground (continental U.S.). Most all black or all dark gray sets are in stock, but we will let you know upon your order.


If you ordered a custom set, then it will take 8-10 weeks (occasionally longer) to arrive from Japan due to custom manufacturing, freight time, and US customs holding time.

Maybe! Contact us to see if your specific vehicle isn't listed on our site, or if you have any questions about the application.

We do have other applications such as passenger vehicles and two door cars as well. Just contact us!

Need just a bottom cushion replacement or another single piece? Contact us for pricing.

We can also supply just the front or rear seats if that is all you need.

Since our seat covers are manufactured for every application specifically, they account for features like these in your interior. Our development team uses a laser guided measuring system to ensure the best fitment for our seat covers.

For straps to fold down seats, they will include a cutout for those to loop through.  For bottom plastic trim on your front seats, the covers are meant to tuck in to those for a great, OEM+ fitment.

Yes, our seat covers are made with special stitching construction on our per application basis (not universal). The design allow for our covers to break at the specific points where the side airbags will detonate.

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