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Writer's pictureRadiant Made Simple

What type of glycol is needed and how much is needed for radiant floor heat?

When installing a radiant floor heating system, it is important to consider the type of glycol and the amount required for the system. Glycol is an essential component of a hydronic radiant floor heating system, as it prevents the water in the system from freezing and provides lubrication for the pump. In this article, we will explore the types of glycol needed and how much is required for radiant floor heating.


The two main types of glycol used in radiant floor heating systems are propylene glycol and ethylene glycol. Propylene glycol is the most common type of glycol used in radiant floor heating systems, as it is non-toxic and has a low toxicity level. Ethylene glycol, on the other hand, is toxic and should not be used in residential applications.


The amount of glycol required for a radiant floor heating system will depend on several factors, including the size of the system and the climate in which it is installed. A general rule of thumb is to use a 20-30% glycol mixture, which means that 20-30% of the volume of the water in the system is glycol.



To calculate the amount of glycol required for a radiant floor heating system, follow these steps:


Determine the total volume of the system: This includes the volume of the piping, the heat source, and any expansion tanks or pressure relief valves.


Calculate the volume of water in the system: This can be done by subtracting the volume of the piping, heat source, and other components from the total volume of the system.


Calculate the amount of glycol required: Multiply the volume of water in the system by the desired glycol percentage (20-30%). For example, if the volume of water in the system is 50 gallons and a 30% glycol mixture is desired, then 15 gallons of glycol are required.


It is important to note that using too much glycol can reduce the efficiency of the heating system, as glycol has a lower thermal conductivity than water. Additionally, the glycol mixture should be tested regularly to ensure that it is at the appropriate level and that the system is functioning properly.


In conclusion, the type of glycol and the amount required for a radiant floor heating system are important considerations for ensuring the efficient and effective operation of the system. Propylene glycol is the most common type of glycol used in residential applications, and a 20-30% glycol mixture is recommended. By calculating the amount of glycol required based on the size of the system and the desired glycol percentage, homeowners can ensure that their radiant floor heating system is operating at its optimal level.


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