How A Block Heater Can Improve Your Winter Fuel Economy

Block heaters are just for vehicles like diesels used in areas that frequently see ambient temperatures below freezing, right? Well not anymore! If you’re trying to maximize your fuel economy, whether your drive a gas or diesel powered vehicle, or even a hybrid, a block heater can help you squeeze the last few miles out of every gallon. Block heaters were originally used to ensure that vehicles could start in very cold weather. Nowadays, the average driver, in warmer areas, can use a block heater to pre-heat their engine.

There are two main reasons for why a block heater improves winter fuel economy. One is reduced friction due to the oil being pre-warmed and second is the fact that your vehicle will reach its optimum operating temperature much more quickly and will use fuel more efficiently. Let me explain…

When your engine is cold and you first start it up, it isn’t operating at its peak efficiency. The reason for this is that vehicles use more fuel than typical and is necessary compared to when they have reached their optimum temperature. Vehicle engines do this in order to prevent stalling and improve cold starting. With a block heater, the engine is preheated and therefore closer to its optimum operating temperature and will therefore consume less fuel.

When oil, which is vital for the operation of any engine, is cold, it becomes thicker and doesn’t flow as well as it would if it were already warmed up and leads to increased friction and wear of the engine components. The wear issue aside for the scope of this hub, the increased friction due to cold oil means you will be consuming more fuel to overcome this friction, leading to a waste of fuel. Using a block heater helps reduce this friction by warming the oil, albeit indirectly unless you use an oil pan warmer or an oil-dipstick heating element. Since a block heater will be heating the engine, the oil and anti-freeze or coolant will also be warmed as well. As the oil is warmer, its viscosity (or thickness, density) is reduced and it flows more easily and coats the engine components.

You might wonder why on earth some owners of hybrids would use block heaters or why I would suggest it. Well hybrids are more efficient than their conventionally fueled counterparts, yet they still have an internal combustion engine that still functions more or less the same as every engine in a non-hybrid vehicle. When the engine in a hybrid car is cold and hasn’t achieved its optimum operating temperature, the hybrid will not shut its engine down when it comes to a halt at an intersection or traffic light. The reason for this is that the car is programmed to continue running its engine until it has achieved its optimum operating temperature. This is fine and dandy if you’re on the highway, where more than likely the engine will be operating anyway, yet it can reduce your fuel economy in city driving or if you make frequent stops, which is where hybrids are supposed to get better fuel economy. Using a block heater allows the hybrid’s engine to reach its optimum operating temperature quickly, just as with a regular vehicle, but it also means that the engine may be shut down at stops like normal.

While it can be quite easy for the mechanically inclined, I highly recommend that you have your dealer install it or purchase the part yourself and have a mechanic install it for you. Some vehicles have a port on the front bumper for a block heater plug to be place through, though some vehicles don’t have this and the plug will have to hang out from beneath the engine bay hood. For most people, block heaters should be used no more than two to three hours before you intend to drive. If your place of work has conveniently placed electrical outlets near any parking spaces, ask if you may plug your vehicle in and carry an extension cord of sufficient length in your trunk.