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What is Antifreeze?

Propylene Glycol is the main ingredient in what is commonly called antifreeze for heating systems, and its use is a common strategy for protecting hydronic heating systems and the associated piping in cold climates. Glycol lowers the freezing temp of the water it is added to, reducing the risk of frozen pipes where they might be exposed to below freezing temperatures during cold winters. 

Why is Antifreeze Important?

Weather in the northeast can get to well below freezing temperatures. Should your heating equipment fail or if you have exposed plumbing to unheated locations in the home like a garage or attic, it doesn’t take long for pipes to start freezing. Frozen pipes lead to bursting followed by property damage. Because the Glycol lowers the freezing point of the fluid in your system, maintaining a suitable level of antifreeze helps prevent such catastrophes.

What Causes Antifreeze to Become Less Effective?

  • Antifreeze has a limited lifespan, typically between 2-5 years depending on the type and quality of the product. Every time the water heats up, some of the Glycol breaks down and increases the acidity of the hydronic fluid. The corrosion inhibitors in the antifreeze neutralize the acid, but over time become less and less effective causing the hydronic fluid to become corrosive. 
  • Dilution: Antifreeze can become diluted if water is added to the HVAC system because some has leaked out or a piping repair is made. Any dilution of the antifreeze will reduce its effectiveness in preventing freezing. 
  • Contamination: Antifreeze can become contaminated with dirt, debris, and other particles that can clog the system and reduce its efficiency. This can happen if the HVAC system is not properly maintained, or if there is a leak in the system that allows contaminants to enter.

How Do I Know If My Antifreeze Isn’t Working?

Without waiting until you experience frozen pipes, the best way to know if the antifreeze in your system is still effective is to have a certified technician test it. They will use a refractometer to measure the freezing point, do a reagent test for the strength of the corrosion inhibitor, and advise if additional antifreeze or corrosion inhibitor should be added. 

What to Do & What to Expect from a Levco Technician

If you suspect that the antifreeze in your heating system is not working properly, has not been tested recently, or has never been added to your system, the first thing you should do is contact a qualified technician to test the system. You may also ask your Levco technician during an annual heating tune up to test the freeze point of your hydronic fluid. He only needs a few drops. 

A Levco technician will test for the freeze point of your system’s antifreeze. When your system’s antifreeze readings indicate that the freeze point is too low, more antifreeze should be added to the system. The ideal freeze point is -10F (42% glycol) and the minimum safe freeze point is 11F (25% glycol). The amount of antifreeze needed can be calculated by measuring or estimating the fluid capacity of your system.

While Glycol can be expensive and is sold by the gallon, the cost is small compared to the potential damage to your home frozen pipes may cause. Adding the antifreeze does not take long and depending on how many gallons your system needs can be completed during a service visit.