Do not add antifreeze to underfloor heating as this will have an impact.
Correct antifreeze measures should be:
1. When there is no one at home for a short time (within a week), the boiler temperature can be adjusted. at the lowest. At this time, the boiler will enter low temperature antifreeze mode.
2. When no one is home for a long period of time, drain all water from the boiler and heating system. However, it should be noted that before doing this, please fully consider other internal pipes, for example confirming that the water pipe will never freeze. Otherwise, do not turn off the boiler and leave it running at low temperature. The underfloor heating only has water in it and I haven't heard of filling it with antifreeze? Even if your home doesn't need underfloor heating in winter. You can also drain the water betweenthe boiler and the water distributor. Water pipes under the ground will not freeze and explode. The full name of antifreeze should be called antifreeze coolant, which means coolant with antifreeze function. Antifreeze can prevent coolant from freezing and cracking the radiator and freezing the engine's cylinder block or cylinder head during cold winter parking. But a misunderstanding must be cleared up. Antifreeze is not just for winter, it must be used all year round.
There is no special formula of underfloor heating antifreeze on the market, because usually if you do not turn on the underfloor heating in winter, you have to blow the water, otherwise it will cause freezing and cracking.
It is recommended to consult professionals here. Inferior automotive antifreeze can easily cause explosions. So never do the work yourself.