Hot Dawg® Separated Combustion Heater

Hot Dawg® Separated Combustion Heater


$2,503.55 Regular price
  • Ships directly from manufacturer - departs in 6-10 weeks

Model HDS Hot Dawg® Separated Heater Combustion Units are a convenient and affordable way to keep your greenhouse plants warm for winter growing. The separated combustion Hot Dawg draws its combustion air from outside to ensure that the unit always has plenty of fresh, clean air to breathe. This fresh-air supply reduces common concerns about dusty, dirty or humid applications. In addition, by drawing the combustion air from the outside, the overall heating efficiency is increased.

Advantages of Hot Dawg Space Heaters

The Hot Dawg® by Modine is designed to generate heat without the expense or hassle of a regular HVAC setup. You don't even need electricity! Here are some of the ways these heaters outperform other units:

  • 100% outside air for combustion
  • Sealed compartment protects combination gas control
  • Ignition control
  • Manifold and burner
  • Horizontal or vertical concentric venting
  • 80% thermal efficiency
  • Field convertible to propane
  • 100% shutoff with continuous retry

In addition to greenhouses, the Hot Dawg is also an excellent combustion garage heater, It's available as an indoor propane heater, natural gas heater or LP (liquid petroleum) heater with free shipping and a 10-year warranty.

Install a Modine Hot Dawg separated combustion heater to keep plants, vehicles, equipment and people warm during the winter. Also known as a sealed combustion heater, these units have a design that uses outside air for the combustion process with a secondary exhaust vent. This makes the heater more efficient and prevents damage from indoor air contaminants. It also stops dangerous gas exhaust products from entering the air you and your plants breathe. No electricity is needed, letting you install the heater wherever you have the appropriate venting.

Greenhouse Megastore has a variety of Modine combustion space heater models that burn at 80% efficiency. Maximum hourly output ranges from 24,000 BTUs (single-car garage and small greenhouses) to 100,000 BTUs (any open structure up to 1,200 square feet). You can order a natural gas, liquid petroleum or propane heater that is ultra-quiet. The heat exchanger has a full 10-year warranty, so you can count on its operation for any growing or living space.

Hot Dawg Combustion Space Heater Features:

  • Less maintenance in dusty environments.
  • Improved efficiency by using outside air for combustion.
  • Greater durability in "hostile" environments (environments possessing substances that may deteriorate the performance of the unit).
  • External thermostat and gas connections.
  • Hush-puppy quiet operation.
  • Uses natural, liquid petroleum or propane gas.
  • Certified for residential, commercial and industrial use.
  • Low-profile design and neutral color to blend in with décor.
  • Lightweight - easily installs one inch from the ceiling with only two angle brackets (included).
  • Install quickly and easily with field wiring connections and knockouts for quick access to gas and electricity.
  • Standard power exhaust simplifies side-wall or roof venting with small-diameter vent piping.
  • Versatile design allows for right- or left-hand controls and installation. Gas, electrical and flue connections can be changed from one side to the other by simply flipping the Hot Dawg over.
  • Permanently lubricated motor for trouble-free dependability.
  • Full 10-year warranty on the heat exchanger (2 years on all other components).

Dimensions and Diagrams

Dimensions, Diagrams and Specifications (PDF)

Modine Greenhouse Heating Solutions (PDF)

Wiring Diagrams (PDF)

Performance Specifications

Model Input BTUH Output BTUH Vent Size CFM @ 70°F
HD30 30,000 24,000 3" 505
HD45 45,000 36,000 3" 720
HD60 60,000 48,000 4" 990
HD75 75,000 60,000 4" 1160
HD100 100,000 80,000 4" 1460
HD125 125,000 100,000 4" 1850

*Do not locate any gas-fired unit in areas with chlorinated, halogenated or acidic vapors in atmosphere.


Many of our customers happily report that purchasing a Hot Dawg heater from the Greenhouse Megastore helped them save 50% or more off the unit price received from a local HVAC installer. However, for safety reasons and to minimize installation problems, Modine strongly recommends having a licensed HVAC technician install your Hot Dawg heater. Although we are happy to offer limited technical support for your Hot Dawg purchase, we cannot install the heater for you over the phone nor are we able to troubleshoot problems you may experience if you choose to install the heater yourself. By purchasing this heater from us, you accept sole responsibility for installation and agree to abide by Modine's limited warranty.

Comparison Chart

Modine HD-Series vs. Sterling RF-Series

Specification Modine HD-Series Sterling RF-Series Comments
BTU Range 30 - 125 MBH 30 - 90 MBH Modine covers more applications
Minimum Efficiency 80% 80% Same non-condensing high efficiency
Blower Fan Units
(HDB model only)
60 - 125 MBH Not Available Modine covers more applications
Casing Paint Polyester Powder Wet Enamel Modine units will look better longer
Quiet Swept Wing Fans 100 and 125 MBH Not Available Larger Modine units are quieter
Heat Exchanger Gauge 18 Gauge 20 Gauge Modine heat exchangers are heavier gauge
Optional Stainless Steel Yes Not Available Modine covers more applications for corrosive environments
T.E. Fan Motor Standard Yes No Modine motors are protected for longer life
Power Vented X-Changer Warranty
(HDS and HDC models only)
10 Years 10 Years Same 10 year heat exchanger warranty
Sep. Comb. X Changer Warranty
(HDS & HDC models only
10 Years 5 Years Modine separated combustion units warrantied longer
Component Warranty 2 Years 1 Year Modine parts warrantied longer

Additional Information


Residential Owners Manual (PDF)


Modine offers a 10-year limited warranty on the heat exchanger and a two-year limited warranty on all other components. Please note this warranty covers parts only and does not cover any labor costs associated with repairing the heater. View Warranty (PDF)

Product Video

Heater Warranty and Return Policy

It is the customer's responsibility to carefully inspect heaters for damage before accepting delivery since heaters are usually not returnable once delivery is accepted. Heaters with obvious damage should be refused and you should contact Greenhouse Megastore customer service to arrange a replacement unit. Once delivery is accepted, Greenhouse Megastore will gladly provide replacement parts under the manufacturer's warranty to repair damaged or defective heaters. However, this warranty does not include any labor costs associated with installing these parts. Warranty issues should be diagnosed by a certified HVAC technician since parts deemed not to be defective by the manufacturer are not available for credit back to the customer. Specific warranty policies vary by manufacturer but typically cover replacement parts as indicated above up to one year after purchase. Please contact Greenhouse Megastore customer service if you have any questions about the warranty for your specific heater.

Recently viewed

Customer Reviews

Be the first to write a review