Does My Car Need a Block Heater During Winter?

What is a block heater?

especially in cold climates. It typically heats the engine coolant or oil, making it easier for the engine to start in freezing temperatures. Block heaters are especially common in places with harsh winters, such as most regions in Canada.

Benefits of using a Block Heater

Using a block heater in cold weather offers several benefits for your vehicle and overall convenience. Here's a detailed breakdown:

1. Easier Engine Starting

• In freezing temperatures, engine oil becomes thicker, making it harder for the engine to turn over.
• A block heater warms the engine block and fluids, allowing the vehicle to start more smoothly and reliably.

2. Reduced Engine Wear

• Cold starts cause more wear and tear on an engine because the oil takes longer to circulate and lubricate critical components.
• Pre-warming the engine with a block heater reduces this wear, extending engine life.

Read more: How Long Should You Warm Up Your Car in Winter in Canada?

3. Improved Fuel Efficiency

• Cold engines require more fuel to reach optimal operating temperatures.
• A block heater helps the engine warm up faster, improving fuel economy, especially during short trips in cold weather.

4. Lower Emissions

• A cold engine emits more pollutants because the combustion process is less efficient.
• Pre-warming reduces these emissions, making your vehicle more environmentally friendly.

5. Enhanced Battery Performance

• Batteries lose efficiency in cold weather, making it harder for them to provide the power needed to start the engine.
• By pre-heating the engine, the block heater reduces the strain on the battery, improving reliability and extending battery life.

Read more: Ultimate Car Battery Guide: How to Charge, Maintain, Replace, and more

6. Greater Comfort

• Warming the engine before starting can also help the vehicle’s heating system work faster, providing cabin heat sooner on frigid mornings.

7. Preventing Engine Damage

• In extreme cold (e.g., below -20°C or -4°F), engine components and fluids can freeze or become sluggish.
• A block heater prevents this, protecting the engine from potential damage caused by ice or extreme contraction.

8. Saves Time and Stress

• Knowing your vehicle will start reliably in the morning reduces stress and hassle during harsh winters.
• It eliminates the need for prolonged idling to warm up the engine, saving time.

How does a block heater work?

A block heater works by using electrical energy to heat the engine block and its components, such as the engine coolant or oil, to make starting easier in cold weather. Here’s a step-by-step explanation of how it works:

Installation and Connection

• A block heater is installed either directly into the engine block (e.g., in a freeze plug opening) or mounted externally on components like the oil pan or engine block.
• It is powered by an external electrical source, usually through a standard household outlet, connected with an extension cord.

Heating Element

• The block heater contains a heating element, much like an electric kettle or immersion heater.
• When plugged in, the heating element warms the surrounding metal, engine coolant, or oil, depending on the type of heater.

Heat Distribution

• Internal heaters (e.g., freeze plug or inline coolant heaters):
• These are installed inside or near the engine's coolant system.
• They heat the coolant, which in turn warms the engine block and internal components.
• External heaters (e.g., oil pan or magnetic heaters):
• These are mounted externally and directly heat the oil or engine block surface.

Maintaining Warmth

• The heated components retain and distribute warmth through conduction and, in some cases, through slight convection within the cooling system.
• The warm coolant or oil helps keep the entire engine block at a higher temperature, preventing freezing and reducing the viscosity of the fluids.

So, does your car really need a block heater? The answer is ‘maybe’.

If you frequently encounter extreme cold in the winter, or live in a particularly northern part of the country, you’re more likely to need a block heater. In the far north, some drivers even install multiple block heaters to their engines, like putting on an extra heated blanket on the coldest nights.

Making a gasoline engine fire up at forty below is extremely difficult but today’s automotive engineers have got it pretty figured out. In fact, the latest synthetic engine oil technology and direct fuel injection systems found in modern engines make life easier on your engine, even when starting from frozen on the very coldest mornings.

If you’re running a properly maintained modern car with synthetic oil, quality fuel and a healthy battery that’s been tested in the fall before the cold weather sets in, chances are even less likely that you’ll need a block heater.

The point is, a block heater can be a nice thing to have, but it can be overkill in a lot of applications.  Of course, you only need to use it when required.

When to use a block heater on a diesel engine

Using a block heater on a diesel engine is especially important in cold climates because diesel engines are more sensitive to low temperatures than gasoline engines. This is due to the higher compression ratio in diesel engines and the fact that diesel fuel can gel in extreme cold, making starting more difficult.

Here’s when to use a block heater on a diesel engine:

1. Temperature Threshold

• Below -15°C (5°F): It is strongly recommended to use a block heater for diesel engines.
• Below -20°C (-4°F): It becomes essential. At this temperature, diesel fuel can start to gel, and the engine oil becomes much thicker, making the engine harder to crank.

2. Cold Starts in Severe Winter

• If your vehicle has been parked for more than 4-6 hours in subzero temperatures, plug in the block heater.
• Even if temperatures are not extreme but hover near freezing, using a block heater can help ensure smoother starts and reduce strain on the battery.

3. Short Daily Drives

• If you make short trips in winter, the engine may not have enough time to warm up fully during driving.
• Using a block heater before starting ensures the engine is already partially warm, which reduces engine wear and improves fuel efficiency.

How much does a block heater cost?

Most vehicles can have a block heater installed at any point in their life, and the heater itself will run $80 - $150 for most mainstream models, with installation usually taking an hour or so at your local shop’s rate. As a ballpark, expect a bill of $175 to $300 for parts and labour to have the block heater professionally installed. 

Though a block heater can be a powerful weapon in your winter-busting arsenal, don’t underestimate the importance of a quality synthetic engine oil, and a healthy battery, for maximum cold-start confidence on the coldest days of the year.

Do electric vehicles need a block heater?

Electric vehicles (EVs) do not require a traditional block heater because they don’t have an internal combustion engine (ICE) that needs pre-heating. Block heaters are specifically designed to warm engine components, such as oil or coolant, in gas or diesel-powered vehicles.

However, EVs still face challenges in cold weather, and while they don’t use block heaters, there are other important systems and considerations for EVs in winter:

Cold Weather Challenges for EVs

EVs have other issues to address in cold temperatures:

1. Battery Performance Drops:
• Cold weather reduces an EV battery's efficiency, resulting in a shorter driving range.
• EV batteries work best at moderate temperatures (20–25°C). In cold weather, chemical reactions in the battery slow down, reducing its ability to hold and deliver power.
2. Cabin Heating Demands:
• Unlike ICE vehicles, EVs can’t rely on waste heat from the engine to warm the cabin. Instead, they use electric heaters or heat pumps, which drain the battery further.
3. Slower Charging Times:
• In cold weather, charging an EV battery can take longer, as the battery management system (BMS) restricts the charging rate to protect the battery.

How EVs Handle Cold Weather

Instead of block heaters, EVs use battery thermal management systems (BTMS) and pre-conditioning features to manage performance:

1. Battery Preconditioning:
• Many EVs allow you to preheat the battery while the car is plugged in.
• Preconditioning warms the battery to its optimal operating temperature, ensuring better range and performance.
2. Cabin Preconditioning:
• Drivers can heat the cabin using a smartphone app or in-car settings while the EV is still charging. This avoids draining the battery while driving.
3. Battery Warmers:
• Some EVs are equipped with battery warmers or use onboard heat pumps to maintain battery temperature in extreme cold.

Recommendations for EV Owners in Cold Weather

While block heaters are unnecessary, here are some tips to improve EV performance in winter:

• Precondition the battery and cabin before driving.
• Keep the vehicle plugged in when temperatures are extremely low.
• Use seat heaters instead of cabin heaters to conserve energy.
• Plan for reduced range and factor in extra time for charging.