How Long Will Rv Battery Last Running Furnace

As an avid RVer, I understand the importance of knowing how long your RV battery will last when running the furnace. Whether you’re on a winter camping trip or using your RV as a mobile home, ensuring that you have enough power to keep the furnace running is crucial. Let’s dive deep into this topic and explore the factors that determine the duration of your RV battery when running the furnace.

Understanding Your RV Battery

RV batteries come in different types, including lead-acid batteries, gel cell batteries, and AGM (Absorbent Glass Mat) batteries. The capacity of your RV battery is typically measured in amp-hours (Ah), which indicates how much current the battery can provide over a specific period.

Factors Affecting Battery Life

Several factors can influence the longevity of your RV battery when running the furnace. The efficiency of the furnace, outside temperature, insulation of the RV, and the condition of the battery all play a role in determining how long your battery will last.

Calculating Battery Run Time

To estimate how long your RV battery will last when running the furnace, you can use the following formula:

Battery Life (in hours) = Battery Capacity (in amp-hours) / Furnace Current Draw (in amps)

Furnace Current Draw

Most RV furnaces draw between 7 to 10 amps when in operation. However, it’s essential to check the specific current draw of your furnace, which can be found in the user manual or labeled on the furnace itself.

Battery Capacity

Suppose your RV battery has a capacity of 100 amp-hours. Using the formula above, if your furnace draws 10 amps, the estimated battery life would be 10 hours (100 Ah / 10 A = 10 hours).

Conserving Battery Power

While it’s essential to know the estimated battery life when running the furnace, conserving battery power can significantly extend its duration. Implementing energy-saving practices such as using propane heaters, insulating the RV, and minimizing heat loss can help preserve battery power and prolong its life.


Understanding how long your RV battery will last when running the furnace is vital for planning your trips and ensuring a comfortable living environment in your RV. By considering the battery capacity, furnace current draw, and implementing energy-saving strategies, you can make the most of your RV battery while staying warm and cozy during your adventures.