How Much Electricity Do Block Heaters Use? A Comprehensive Guide

Block heaters, a common sight in colder climates, are a lifeline for many vehicle owners.

But how much electricity do they consume?

And what does it cost to run a block heater?

In this article, we’ll delve into these questions and more, providing a comprehensive guide for both UK and US audiences.


Understanding Block Heaters

Block heaters are devices installed in a vehicle’s engine compartment.

They pre-warm the engine, making it easier to start in cold weather and reducing wear and tear.

But like any device, they consume electricity.

So, how much power does a block heater draw?

Does a Block Heater Draw a Lot of Power?

Block heaters typically draw between 400 and 1500 watts of power, depending on the model and the size of the engine they’re heating.

This is comparable to running a small to medium-sized home appliance.

However, the cost can add up over time, especially if you’re using the heater regularly throughout the winter months.

How Much Does It Cost to Run a Block Heater?

The cost of running a block heater depends on two factors: the power it draws and the cost of electricity in your area.

In the US, the average cost of electricity is around 13 cents per kilowatt-hour, while in the UK, it’s approximately 20 pence.

To calculate the cost, you’ll need to convert the heater’s power from watts to kilowatts (1 kilowatt = 1000 watts), then multiply by the number of hours you run the heater and the cost of electricity.

For example, if you run a 1000-watt heater for 3 hours a day at 13 cents per kilowatt-hour, it would cost around 39 cents per day.

Can I Leave My Block Heater Plugged in All Day?

While it’s technically possible to leave a block heater plugged in all day, it’s generally not recommended.

Not only does it consume more electricity (and therefore cost more), but it can also lead to unnecessary wear on the heater itself.

Most manufacturers recommend plugging in the heater for 2-4 hours before you plan to drive.

Is 1 Hour Enough for a Block Heater?

One hour might be enough for a block heater to warm up the engine in mild cold, but in severe cold conditions, it’s usually not sufficient.

As mentioned earlier, 2-4 hours is a more common recommendation.

However, the exact time can vary depending on the specific heater, the size of the engine, and the outside temperature.

Insights from Online Discussions

Online forums and discussions provide a wealth of real-world experiences and insights.

For example, a Quora discussion reveals that many users find the cost of running a block heater to be quite reasonable, especially considering the benefits of easier starts and less engine wear.

On the Diesel Truck Resource forum, users discuss various strategies for minimizing the cost of running a block heater, such as using a timer to turn on the heater a few hours before driving.

The Heavy Duty Parts Report provides tips on how to lower the electricity costs of block heaters, such as investing in a more energy-efficient model or using a thermal blanket to retain heat.

A Houzz discussion provides insights into the current draw of different block heaters, with users reporting values ranging from 400 to 1500 watts.

Finally, a Powerstroke forum thread discusses the electrical usage of block heaters in detail, with many users noting that the cost is a small price to pay for the benefits of a warm engine on a cold morning.


Block heaters, while consuming electricity, offer significant benefits in terms of vehicle performance and longevity in cold climates.

The cost of running a block heater can vary, but with careful use and some energy-saving strategies, it can be a worthwhile investment for many drivers in the UK and the US.

As always, it’s important to consider your specific circumstances and consult your vehicle’s manufacturer for the best advice.

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