Diesel engines require more heat to start in cold weather compared to gasoline engines. This is why most diesel vehicles come equipped with diesel engine block heaters. But how many watts do these engine block heaters consume? As a professional diesel engine parts supplier, I will help you find it out in this article.
What Is An Engine Block Heater?
An engine block heater is an electric heating device that warms the engine coolant to make diesel engine starts easier in extremely cold temperatures below 0°F (-18°C).
Engine block heaters heat the engine block and circulating coolant to prevent oil from losing viscosity and diesel fuel from gelling.
They plug into standard 110v or 220v household outlets and warm engines in parked vehicles without running the engine. Engine block heaters are standard in diesels in colder regions and plug into outlets commonly seen at parking spaces outside homes.
How Many Watts Does A Diesel Engine Block Heater Use?
On average, a diesel engine block heater draws 1500 watts of power. But depending on the type, size, and plugs used, heaters can draw from as little 750 watts to as much as 3000 watts.
A 1500 watt diesel block heater is sufficient to warm over most diesel cars, SUVs, and light-to-midsized trucks. 3000 watt diesel block heaters are commonly used on larger heavy-duty trucks and equipment.
Factors That Determine Block Heater Wattage
The wattage a diesel engine block heater draws depends on:
1. Coolant Capacity
Larger diesel engines hold more coolant and therefore require larger block heaters that draw more power to maintain temperature.
Smaller passenger cars often use lower 750w to 1500w bock heaters while class 4-7 buses and semi trucks use heaters up to 3000 watts.
2. Ambient Temperature
Diesel vehicles operated in colder winter climates often equip larger 1500w to 3000w block heaters as standard to compensate for extremely cold weather.
Meanwhile, diesel cars driven in milder climates can get away with smaller 750w block heaters.
3. Plug Type
Engine block heaters normally connect to household outlets protected by a 15 to 20 amp circuit breaker through a three-prong plug.
Common plug types include:
- 15 Amp Plugs – Supportup to 1500 watts
- 20 Amp Plugs – Accommodate 2000 to 3000 watt diesel block heaters.
15 vs 20 amp plug types limit the wattage of the heater.
How Much Electricity Do Diesel Block Heaters Use?
A typical 1500 watt diesel block heater running for 8 hours uses:
- 12 Kilowatt hours (kWh) of electricity
- Costs $1.92 per day (at $0.16 per kWh) to operate
- $57.60 per month of plugged-in block heater operation
Diesel block heater energy use adds up over winter months especially when operating fleets of diesel-powered service body trucks, school buses, and heavy equipment.
Commercial fleets often equip larger 3000 watt or bigger block heaters which use proportionally more electricity when plugged in overnight.
How Long Should You Run A Diesel Block Heater?
2 to 4 hours is ideal runtime for a diesel block heater before starting the engine. Even in temperatures below 0°F, most modern diesel engines start fine with 2 to 3 hours of block heater warmup.
Excessive idling or running the block heater overnight is unnecessary. Modern synthetic diesel motor oils retain viscosity much better than older conventional oils making extended warmup pointless.
Diesel mechanics recommend plugging in the block heater:
- At least 2 hours before starting in temperatures above 0°F.
- Up to 4 hours for temperatures -10°F and below.
Using timers helps control block heater runtime preventing excessive idling and fuel waste.
More Efficient Diesel Block Heater Alternatives
Extremely cold weather diesel block heater operation consumes substantial electricity running up costs. Here are some alternatives to help cut diesel block heater energy usage:
Diesel Fuel Additives
Winter diesel fuel additives added to each fill-up like Howes Diesel Treat prevent fuel gelling so engines turnover easier without relying solely on block heater warmup.
Oil Pan Heater
An oil pan heater offers faster warmup directly heating the engine oil instead of the coolant. Their lower wattage compared to full block heaters draws less energy.
Engine Warmer
Engine warmers like the FrostBlock strap onto the engine block itself using less power warming only the metal instead of larger masses of coolant. Quicker warmup means shorter runtime.
Block Heater Timers
Block heater timers manage runtime through built-in thermostats conserving electricity. Timers allow adjusting warmup duration based on ambient temperature.
Remote Block Heater Control Systems
Remote diesel block heater controllers like PowerSync throttle block heaters on and off based on weather data enabling fleets to cut block heater energy usage by over 90 percent.
Advanced control technology minimizes heater runtime while ensuring vehicles start reliably even in extreme winter conditions.
In Conclusion
So on average, 1500 watts is the power consumption of a typical diesel engine block heater. Properly managing block heater operation avoids excessive idling, saves fuel, and reduces electricity costs for light and heavy-duty diesel vehicles.
Implementing alternative engine warmup methods further lowers diesel block heater energy usage over winter months.