Buzz
If you own a snowblower, lawnmower, or any gasoline-powered equipment, you likely have a gas can stored for fueling it. However, if that gas was purchased during winter and intended for summer use, or the other way around, you might notice your equipment underperforming. The culprit? The gasoline itself.
Winter gasoline features a higher Reid Vapor Pressure (RVP)
You’re probably familiar with how water behaves in different temperatures. For instance, a puddle of water on your driveway will evaporate rapidly in the summer heat but linger much longer on a cold day, if it evaporates at all.
Temperature significantly impacts gasoline performance. During colder months, gasoline must remain sufficiently volatile to vaporize and ignite your engine. Winter gasoline is specially designed with a higher Reid vapor pressure (RVP) to ensure it evaporates effectively even in freezing conditions.
For these reasons, winter gasoline is essential for powering snowblowers or generators in colder months. Using summer gasoline during winter can lead to starting difficulties and engine misfires.
Summer gasoline offers better fuel efficiency
Summer gasoline, on the other hand, is formulated with a lower RVP to prevent excessive evaporation in hot weather. Excessive evaporation can harm your engine and increase harmful emissions.
To curb emissions, the EPA enforces an RVP limit for gasoline sold in summer (from June 1 to September 15). Additionally, individual states may impose their own emissions and RVP regulations.
Using summer gasoline in your lawnmower during warmer months is not only ideal but also more fuel-efficient, allowing you to cover more ground with less fuel.
Gasoline has a limited shelf life unless treated properly
Storing gasoline from one season to another poses another problem: it eventually goes bad!
Typically, gasoline remains usable for three to six months after purchase, though storage conditions play a role. In summer heat, its lifespan shortens. Additionally, the type of gasoline matters—summer blends often contain ethanol, which reduces their shelf life to one to three months.
If you anticipate not using a gas can soon, adding a fuel stabilizer like Sta-bil can extend its usability to around two years. Note that this won’t revive old gas but can preserve fresh gas for future use.
If you’ve discovered that old can of gas is no longer usable, you can safely dispose of it at a hazardous waste facility or check for local hazardous waste collection events. For additional guidance, we’ve provided more details on how to properly discard old gasoline.
