Anti freeze?

[Selfbuildsarah]

Someone has just raised something I haven’t come across so far - do we need antifreeze in our ufh?

[JohnMo]

If you are in the build stage and it's likely to see near freezing temperatures and the loops are being left water filled, yes. If no water in system yet, just pressure test with air and leave pressurised.

 

But you could blow out the water and replace with air pressure if already water filled.

 

If house is built and heating system in use, no point. But you do need corrosion inhibitors and biocide (from same company to ensure chemistry compatibility)

Edited April 22 by JohnMo

[Bancroft]

+1 for @JohnMo's comment.  I too was a little confused about this so I spoke to a UFH supplier and they confirmed - it's just there for the commissioning/build period then flush out and replace with water (plus inhibitors/biocide if you feel the need).

[scottishjohn]

are you in a hard water area ?

with no softening treatment on the supply

 something else to consider -as it could scale up your boiler over time 

ask your heating engineer