Glycol Water ratio mix?

Old 12-31-09, 12:14 AM
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Join Date: Dec 2009
Location: Alberta, Canada
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Smile Glycol Water ratio mix?

I was wondering if anyone could help me with the glycol water ratio mix I should use in my system. I am not sure how much information you need so I will try to be as thorough as possible.

I live in a very cold climate (Alberta, Canada) where temperatures have been reaching -40C and if my thermometer is correct this is also -40F. My husband and father in law want to flush the system this spring but we are unsure of the glycol water mix ratio to replace it with. Our house is 3500sq/ft all on one level and the heating system is throughout our concrete floor.

I would really appreciate any help with this and if you need more information please let me know and I will do my best to get it.

Thanks so much for taking the time to try and help me!
Old 12-31-09, 06:44 AM
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Ratio will vary depending on brand and type, and how cold you want protection. Here's a link to the spec sheet for a common brand:

It also has good instructions for how to clean and flush, estimate volume of system, etc.

Note that glycol has lower heat transfer capabilities than straight water, so the average water temperature needed in the slab might go up a bit (maybe 10-15%).
Old 12-31-09, 07:11 AM
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Not sure why you want glycol in your homes heating system.
The point of the system is to keep the house warm, well above freezing. Unless you are leaving the heat off for a long period of time, what is the point of the glycol ?
Do you have long periods of blackouts, or run out of fuel ?

Glycol is a maintenience thing. Too low of a mix, and you end up with a sluddgy mess if the PH goes off, too high and your heat transfer goes down, and it gets harder to move as the viscosity goes up.

If you don't look after it, annually, you could be in for trouble.

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