Among drivers in Spain, there has long been a belief that filling up your car in the early morning, when it’s cooler outside, lets you get more fuel for the same money. The idea is that at low temperatures, gasoline or diesel contracts, allowing a greater volume to fit in the tank. However, engineer and Easygas company head Joseba Barrenengoa set out to see just how accurate this claim really is.
Fuel temperature and its effect on volume
Supporters of early-morning fill-ups are convinced that the lower the temperature, the denser the fuel, so its mass per liter is higher. At first glance, the logic seems solid—physics does show that liquids expand and contract with temperature changes. But in reality, this effect is virtually negligible at gas stations.
The reason is that fuel isn’t stored at the surface, but in special underground tanks. These tanks are set deep enough that the temperature hardly changes throughout the day or even between seasons. It’s typically kept at about 15 degrees Celsius, regardless of whether it’s winter or summer, morning or evening.
Why there’s no difference between morning and evening
Even if the temperature drops to 5°C at night and rises to 25°C during the day, the fuel stored in underground tanks remains at a stable temperature. This means that whether you fill up in the morning, afternoon, or evening, you receive the same volume and density of gasoline or diesel. The surrounding environment has virtually no effect on the properties of the fuel while it is underground.
Therefore, trying to save money by choosing a specific time of day to fill up has no real basis. Experts emphasize that any temperature difference in the fuel at the pump is minimal and cannot affect the number of liters that go into your tank.
Myths and Facts: What Drivers Need to Know
Many drivers still believe old tips passed down from generation to generation. However, modern fuel storage and dispensing technologies have made such advice outdated. In Spain, all stations are equipped with tanks that protect fuel from temperature fluctuations and external influences.
The only real factor that can impact your expenses is changes in fuel prices over the course of a week or month, not the time of day. That’s why drivers should watch price trends and station promotions, rather than the air temperature in the morning or evening.
How Modern Fuel Stations Work
Underground tanks are standard at most European gas stations. They provide not only a stable temperature but also safe storage. This ensures that fuel is not subject to sudden temperature fluctuations, so its physical properties remain unchanged.
Even during periods of extreme heat or cold, the temperature inside the tank changes very little. This allows stations to guarantee consistent fuel quality and volume for all customers, regardless of the time of day or weather conditions.
Tips for Saving on Fuel
If you want to spend less on fuel, experts recommend looking out for promotions and discounts, choosing stations with a strong reputation, and keeping your vehicle in good technical condition. Regularly checking tire pressure, timely filter replacement, and careful driving habits will reduce fuel consumption far more effectively than simply choosing the time to fill up.
It’s also worth remembering that fuel quality at major network gas stations is usually monitored more strictly than at small independent stations. This is another factor that affects both savings and the engine’s longevity.
Did you know: What is Easygas and who is Joseba Barrenechea?
Easygas is a Spanish network of service stations focused on modern customer service standards and transparent pricing. The company actively implements innovative solutions to improve operational efficiency and customer comfort. Easygas is known for its loyalty programs and promotions that help drivers save on regular refueling.
Joseba Barrenengoa is an engineer with many years of experience in fuel technologies and the head of Easygas. He regularly shares expert opinions on car maintenance, fuel specifics, and market trends. Thanks to his professionalism and openness, Easygas has earned the trust of thousands of customers across Spain. Barrenengoa is also actively involved in educational projects aimed at improving drivers’ knowledge and debunking outdated myths related to vehicle use.
