On this page, you will find out how many watts an engine block heater draws.
Keeping your vehicle running smoothly requires a few adjustments. If you’re living in a climate that spends much of winter below freezing, you’ll know all about engine block heaters.
While they are not a necessity for modern cars and trucks, they are still beneficial to keep your engine running smoothly. While keeping engine fluid warm might seem like a wise choice, you might worry about the power consumption of your block heater when plugged in overnight.
Below we will discuss and test engine block heater wattage, explain how to work it out for yourself, and calculate the total electricity required.
How Many Watts is a Car Engine Block Heater?
The average car block heater uses between 300 and 500 watts, while a truck block heater uses 1000 to 2000 watts.
The exact number depends on the size and model of your engine block heater. For example, a small block heater for a car engine draws 400W or less. Contrastingly, a big truck block heater uses over 1800W!
The reason for this difference in power is the size of the heating element. A larger engine, like in a truck, has more engine oil and fluid to warm up. This requires a larger heating element which draws more power.
How to Find Out Your Car Block Heater Wattage
There’s 3 ways you can work out the wattage of an engine block heater.
- Check Product Specification
The quickest way is to look at the engine block heater’s specification. The watts (W) is usually written on a sticker on the device. If not, you can check the user manual or the manufacturer’s website for technical details.
- Use a Wattmeter
A wattmeter is brilliant for getting a live wattage reading and tracking total energy usage of any appliance. You can plug it into your engine block heater to get instant information.
- Wattage Formula or Calculator
If you know the amperage and voltage of your engine block heater you can use this to find the maximum watt rating. Simply use the formula Amps x Volts = Watts. Or you can head over to the ‘Watt Calculator’ to work this out.
Engine Block Heater Wattage Examples
Let’s take a look at specific examples of how many watts a engine block heater draws. Below is a collection of modern engine block heaters with their listed power ratings.
| Engine Block Heater Model | Power Rating (Watts) |
| RS Pro Heating Element | 400 |
| RS Pro Nozzle Heater | 415 |
| Calix Engine Heater | 500 |
| Kat’s Engine Freeze Car Block Heater | 600 |
| Peregrine Coolant Engine Block Heater Kit | 750 |
| Original HOTSTART Engine Block Heater | 1000 |
| Startse Preheater Engine Block Heater | 1800 |
| Auto Truck Engine Coolant Heater | 2000 |
As you can see, the power ratings vary between different engine block heaters. So you should take the time to check your own appliance.
How Much Electricity Does an Engine Block Heater Use?
You can use engine block heater wattage to work out how much electricity it uses. Plus this can be useful in understanding how much it costs to run your car or truck block heater.
A watt (W) is a measurement of power at a single point in time. A watt-hour (Wh) is the total amount of electricity used in an hour. For example, a car block heater drawing 500W would use 500Wh when running for an hour.
Happily, electricity bills are recorded in kilowatt-hours (kWh). A kilowatt is simply 1000 watts. So a 500W engine block heater running for 1 hour uses 0.5kWh.
In reality, you use an engine block heater for 2 hours a day. This means a block heater uses about 1000Wh or 1kWh electricity a day. That’s 30kWh a month.
That’s a rough electricity cost of $0.15 a day or $4.50 a month to run a block heater for two hours a day.
Using an Engine Block Heater Off-Grid
If you’re planning to use your engine block heater in an off-grid situation, like a power outage or remote location, the information above is useful. You can select and install the correct electrical equipment.
You can either use a power inverter, portable power station, or generator to generate AC electricity.
To make sure everything runs smoothly you should check two things on this equipment – wattage capacity and total energy capacity.
Your power source, like a portable power station, should have a wattage output capacity of at least 20% more than your engine block heater. This ensures it will be able to deliver enough power as they are never 100% efficient.
Secondly, you need to ensure your energy source, like a battery, has enough energy to run the block heater for the required amount of time. As we already know, a car block heater uses about 500Wh electricity an hour. This is the equivalent to 41Ah on a 12V battery.
How Many Watts Does a Engine Block Heater Use Summary
I hope you now have a clear understanding of how many watts a engine block heater uses.
What we’ve discovered is that car block heaters use a moderate amount of power, while truck block heaters peak at 2000W! Like any heating element, it needs a decent amount of electricity to generate heat. The good news is that you won’t ever run it for long periods, certainly no more than 4 hours at a time. It’s an efficient way to keep your engine well maintained.
If you’re keen to monitor the energy usage, then it’s best to get an automatic sensor. That way your block heater only switches on when air temperatures drops to -18℃ / 0℉. or use a timer to warm the engine a couple of hours before you drive.
