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Winter Car Heating Guide: How to Deal with Fog, Odors, and Fuel Consumption

冬天汽車暖氣全攻略 l 冬天起霧點算好?有異味點處理?開暖氣更耗油?
Author
Kwiksure Team
Created On
2025-06-28
Edited On
2026-07-21

In the cold winter months, many people turn on their car's heating system to stay warm. However, this often leads to issues like foggy windows, strange odors, and increased fuel consumption. Understanding how your car's heating system works and how to use it properly can help mitigate these problems.

Table of contents
  • Car Heating System: How It Works
  • Three Common Misuses of Car Heating
  • How to Clear Foggy Windows
  • Dealing with Odors
  • Does Heating Increase Fuel Consumption?
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Car Heating System: How It Works

Unlike the air conditioning system, which consists of components like a compressor, cooling fan, and refrigerant, the heating system is simpler. It utilizes the heat generated by the engine to warm the air. This warm air is then directed into the cabin through a series of ducts from the heater core.

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Three Common Misuses of Car Heating

1. Instant Heating 

The car’s heating comes from the engine’s heat. If the engine isn't warm enough, the heater won’t produce warm air immediately and may even put additional strain on the engine. It's advisable to wait about 5 minutes after starting the engine before turning on the heater. You can also check the temperature gauge on the dashboard; when it reaches above 30 degrees Celsius (normal operating temperature is about 90 degrees Celsius), the heater should be effective.

2. Sealing the Cabin

When using the heater, don’t completely close the windows. Prolonged use of the heater can make you feel drowsy, which affects driving safety. It's better to slightly open the windows or enable the outside air circulation to keep the air inside the car fresh.

3. Direct Air to Face 

Directing the warm air straight at your face to warm up quickly can cause dry skin and breathing difficulties. This can be dangerous for the driver. 

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How to Clear Foggy Windows

【冬天汽車暖氣全攻略】冬天起霧點算好?有異味點處理?開暖氣更耗油?

Fogging occurs due to the temperature difference between the inside and outside of the car. To clear fog, direct the warm air towards the windshield. It might take a few minutes for the fog to dissipate, and it usually takes longer than using the air conditioning system for defogging.

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Dealing with Odors

If you notice unpleasant odors when the air conditioning is on, it might be due to bacteria or foreign matter in the air ducts. Parking the car in direct sunlight with the windows open can help kill bacteria and reduce odors. If this doesn’t help, consider using an air conditioner cleaner spray designed for cars. Regularly replacing the cabin air filter is also recommended to maintain air quality.

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Does Heating Increase Fuel Consumption?

【冬天汽車暖氣全攻略】冬天起霧點算好?有異味點處理?開暖氣更耗油?

Since the car's heater uses heat generated by the engine, it generally does not significantly increase fuel consumption. However, if you have the air conditioning (AC) turned on while using the heater, it will activate the AC compressor, which can increase fuel consumption. It’s best to turn off the AC when using the heater.

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Contact Kwiksure to get motor insurance quotes

Kwiksure has over 20 years of experience in the car insurance industry, comparing quotes from over 60 insurers in Hong Kong. Use our online quotation tool now to get a free car insurance quote!

The above information is for reference only. Kwiksure takes no responsibility for the accuracy and timeliness of the information. For the coverage, mode of compensation, benefit limit and premium levels of any specific insurance plan, please refer to the relevant policy terms.

kwiksure_team
Author
Kwiksure Team

Kwiksure is a licensed motor insurance brokerage company with over 20 years of experience in insurance. The company strives to simplify insurance and select the best insurance plans for customers that fit their budget and coverage needs.

Kwiksure provides a range of insurance products, including car insurance, motorcycle insurance, cross-border insurance between Hong Kong and Mainland China, home insurance, travel insurance, domestic helper insurance, and voluntary medical insurance. The team has been named "Best Car Insurance Broker" and "Outstanding Leadership Award" by various media outlets over the years.

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