Why is My Propane Heater Using So Much Propane? A Comprehensive Guide

The primary reason for a propane heater using too much propane is the inability of the liquid fuel to vaporize quickly enough to meet the demand of the furnace, especially in cold weather. This issue is compounded when using small propane tanks, such as 20-pound tanks, which may not be able to supply the volume of vapor needed for a full-size house furnace.

Understanding Propane Behavior in Cold Temperatures

When propane is stored in a tank, it is in a liquid state. As the liquid propane is released through a valve, it converts into a gas. However, when temperatures drop too low, right around -44 degrees Fahrenheit, the propane no longer has the ability to convert into its gaseous form, leading to insufficient fuel supply for the furnace.

Technical Specifications:

  • Propane boils at -43 degrees Fahrenheit, while butane boils at 30 degrees Fahrenheit.
  • The average BTU content per gallon for propane is 91,500, while for butane, it is 102,600.
  • A 20-pound propane tank has a capacity of 432,804 BTU.

The Role of Butane in Propane Mixtures

why is my propane heater using so much propane

Another factor to consider is the presence of butane in the propane mix. Butane boils at a higher temperature than propane, which can cause problems when the temperature drops. In the summer, butane can be a better option due to its higher BTU content per gallon. However, in colder climates, it may not be as suitable for use in propane tanks.

Addressing the Issue of Excessive Propane Consumption

To address this issue, it is recommended to use a proper propane supply instead of small tanks. Additionally, ensuring that the furnace’s BTU output matches the size of the space being heated can help prevent excessive propane usage. Regular maintenance and inspections of the furnace and propane system can also help identify any issues that may be contributing to excessive propane consumption.

DIY Solutions:

  1. Check for leaks in the propane system using a soapy water solution.
  2. Adjust the furnace’s gas pressure valve to the recommended tolerance listed on the data tag.
  3. Insulate the propane tank to prevent it from getting too cold and limiting the propane’s ability to vaporize.
  4. Use a larger propane tank or multiple tanks to ensure a sufficient supply of propane for the furnace.
  5. Regularly maintain and inspect the furnace and propane system to identify any issues that may be contributing to excessive propane consumption.


In summary, the key reasons for a propane heater using too much propane are the inability of liquid propane to vaporize quickly enough in cold weather and the use of small propane tanks that cannot supply the necessary volume of vapor for a full-size house furnace. By understanding the technical specifications of propane and butane, as well as implementing DIY solutions, you can effectively address the issue of excessive propane consumption and ensure your propane heater is running efficiently.