How to Horizontally Vent a Propane Heater: A Comprehensive Guide

Horizontally venting a propane heater is a crucial task that requires careful consideration of safety and efficiency. This comprehensive guide will walk you through the step-by-step process, providing detailed technical information and specific data points to ensure a successful installation.

Selecting the Proper Venting System

When horizontally venting a propane heater, you will need to use a “B-vent” external blower and the appropriate galvanized metal flue pipe or stainless steel venting. It’s important to note that the B-vent is no longer listed as approved for horizontal venting on propane, but stainless steel venting is the approved option for this application.

Vent Kit Requirements

The vent kit you choose should include the following components:

  1. Inducer: The inducer is a critical component that helps draw the exhaust gases out of the heater and through the vent system.
  2. Termination: The termination is the end of the vent system that protrudes outside the building, allowing the exhaust gases to be safely released.

It’s crucial that the vent kit is not just a simple pipe sticking out of the sidewall, as this can compromise the safety and efficiency of the system.

Determining the Minimum Distance for the Blower Installation

how to horizontal vent a propane heater

When venting a propane heater horizontally, the minimum distance required for installing the blower is not explicitly stated in the guidelines. However, it is mentioned that one 90-degree elbow and 7 feet of distance to the outside are typically present.

To ensure proper installation, it’s recommended to consult the manufacturer’s instructions or seek guidance from a professional HVAC technician. They can provide the specific requirements for your particular heater model and ensure the blower is installed at the appropriate distance.

Horizontal Venting for the Hot Dawg 45K Propane Heater

For the Hot Dawg 45K propane heater, horizontal venting with a power exhauster (positive vent pressure) is considered a Class III vent. In this case, you can use double-wall pipe, but it’s best to use the same vent pipe used with tankless water heaters.

Vent Pipe Angle and Length

The vent should be tilted slightly downward, approximately 1/4 inch per foot, to allow any condensation to run out of the vent. The Modine manual for the Hot Dawg 45K heater requires a minimum of 3 feet of vent pipe, with at least 2 feet inside the garage and 12 inches protruding outside, totaling a minimum of 3 feet. It doesn’t matter if some of the 3 feet is outside the building.

Propane Consumption and Run Time

The Hot Dawg 45K propane heater uses approximately 1.5 gallons of propane per hour at maximum output. This means that a 200-pound (48-gallon) propane tank can provide a run time of about 32 hours for this heater.


Horizontally venting a propane heater requires careful attention to detail and adherence to specific guidelines. By following the steps outlined in this comprehensive guide, you can ensure the safe and efficient installation of your propane heater’s venting system. Remember to always consult the manufacturer’s instructions and seek professional assistance if needed to ensure a successful and compliant installation.