I used to WRESTLE with my car to make the engine work.
This problem even becomes more noticeable during the harsh winter season. I tried looking for different extension cords for block heaters, but there are only a limited number of articles out there that help solves this problem.
This is part of why I wrote this blog to become an always-updating resource filled with easy-to-read answers for readers.
What’s the purpose of a car block heater?
Their primary purpose is to keep your engine warm and make it easy for you to start the car.
Think of it like how would bakers typically prepare things in the oven. They would preheat the appliance first before placing the ingredients.
Image 1.1 Charging your block heater
Similarly, this is how your car operates. It will need to preheat before you can ride it down the road.
What usually happens inside a car is that oil will flow toward engine parts. It will then grease it to be ready for function. But during cold winter days, the oil gets mushy, making it a formidable challenge to lubricate the car parts. A block heater helps heat the oil for it to flow easily.
What extension cord should I use for the block heater?
12ga is the recommended extension cord for your block heater.
It is the safest option for beginners who don’t know what to use. However, 10ga is not advisable as it can be slightly larger.
If you want a more technical response, a veteran electrician offered a detailed guide on how you could find out. First, prepare the ambient air temperature by setting it to 7°F above zero. Observing the resistance to cold while making it sit for 3 hours will result in a maximum amp draw of 7.2 amps and increasingly get hotter every hour.
| Time Spent | Electricity Equivalent |
| 15 minutes | 7.0 amps |
| 1 hour | 6.8 amps |
| > 1 hour | Will heat nearby water |
TLDR: To summarize, a block heater will only draw 7.2 amps max.
Block Heater Cord vs. Extension Cord?
They are both the same. What’s important is matching the correct gauge needed. But you want to choose an extension cord for outdoor use and not just any line in the grocery.
Is block heaters worth it? 4 Important Advantages
There are several advantages and disadvantages to using a block heater which we’ll break down one by one below.
1. You spend less money on fuel.
On top of the list are savings on fuel costs. When your car is plugged in, it can save up to a third of fuel consumption.
This calculation also considers the electricity cost for powering up the block heater. It would save you money if we included the electricity cost as part of the total bill.
But you would only save money for up to 20 kilometers.
Any miles more than that don’t account for any savings since your car is running hot then. That 20-kilometer is already far enough to prioritize saving fuel costs for most people.
2. You save money on car repairs & maintenance.
If you treat your car like a baby and constantly monitor its performance, no one will need to remind you when it’s time to clean your car or have it go through maintenance.
It means that you are a proactive type of car owner. Instead of waiting for your car to show some problems and spending another couple of hundred dollars down the drain, you inspect first and prevent any issue from arising.
We can safely assume that you would never leave your car abandoned on a cold winter night but safely tucked with a fitted extension cord to warm it up.
You don’t want to warm up your block heater at the last minute, so instead of plugging it only the night before a critical event, start by spending a few days cycling between plugging sessions to prepare it for use.
3. You get an affordable luxury — a warm car interior.
One overlooked benefit of using a block heater is that it not only prepares your car for travel, but the atmosphere of your car is not the same as the cold outside.
Image 1.2 Warming up the car interiors
It might not be the machine’s primary purpose, but it’s an affordable luxury that everyone deserves to have during the snowy winter months.
They also give off heat in your car windows and windshield.
4. You help save the environment.
Since you emit less fuel needed to warm up your car, it will contribute to fewer greenhouse gas emissions.
The number will immediately drop, and our mother earth will be a little bit healthier if more people try to plug in their block heater.
Read This: Extension Cord vs. Romex (11 Important Things You Should Know)
When should you not use a block heater?
Despite the number of benefits we mentioned, there are a handful of criteria that a block heater is not eligible to use.
First is synthetic oil. The ingredients included won’t make the oil appear mushy. Instead, it is one of the few types of fat that can withstand some of the coldest temperatures on the planet, not requiring you to plug in your car.
Place your car in a warm garage, tent, or area that is not susceptible to extreme colds.
What’s the right temperature before I plug the block heater?
You should plug your car at -15°F (20°C)
Image 1.3 Warm up your car before using
Please don’t wait until below freezing temperatures to plug it in for diesel engines. The temperature should be while it’s still the beginning of wintertime.
How many hours should I plug the block heater?
The answer is 2 – 4 hours, remove once done. Having it plugged in more than the required number of hours will bring no benefit as most block heaters will perfectly warm up your car by the 3rd hour.
Will a block heater damage my car?
No, it won’t. Block heaters won’t needlessly break down, unlike other parts of your car.
But what would most likely damage your vehicle is its extension cord.
An unmonitored extension cord might be prone to fire. To avoid this, inspect the state of your cable, ensuring there are no damages in the wirings before using it. Avoid car wheels touching the cord as this may further hurt the wiring.
Can you leave the block heater overnight?
Yes, if your extension cord has a timer feature.
Image 1.4 Leaving your car plugged in overnight.
It allows you to set it to stop flowing electricity once it reaches 2 – 4 hours.
But if you don’t have that feature, wake up at 6 am to plug it in, then go on with your standard morning routines & chores before driving to work by 9 am.
Is it safe to start my car while the block heater is plugged in?
It’s not advised to start your car while plugged in. You might accidentally drive down the road with the extension cord still plugged in.
Ideally, you want to let it heat for 2 hours minimum. It is excellent for people who might be in a hurry and want to beat the morning traffic.
Do block heaters consume a lot of electricity?
No. It would only consume a considerable chunk of your electrical bill if you left them unattended for more than 4 hours.
Will my block heater warm up the car battery?
Yes, it will help heat it and reduce the stress of your car battery with the amount it would take to start the engine.
If you didn’t plug the block heater beforehand, the battery would consume more energy to get your engines up and running.
Bottom Line:
As we shared some tips on choosing the right extension cord, giving your car enough time to warm up and not rush the process is essential.
