Where has this idea come from that water is insulating? Air is a far better insulator than water. That is why most insulating materials rely on pockets of trapped air. When we go out in the cold we all know to put on many layers so that there is air trapped between each layer. If your clothes got wet you would freeze pretty quickly.cordyman wrote:I read the freezing of water generates heat but how does this favour compared to a never freezing body of insulating water?
Do a simple experiment at home. Measure the air temperature in your house then get a thermometer and fill a bowl with water adding, from the hot tap until the water is the same temp as the air. Move your hand between the air and the water and see which one feels warmest. As you know they are the same temp, the one which feels warmest against your skin is the best insulator because it is not efficiently conducting your body heat away from your skin. (obviously dry your hand after taking it out of the water because evaporating water will feel the coldest).
Yes, water releases heat as it freezes but as Ade has said, once it has frozen it is useless. You need a large body of water to ensure that the freezing process doesn't ever complete, and once it does, it will take a long time to thaw out at winter daytime temperatures. This thawing time will negate any benefits from holding off the freezing.
To my mind, hot water is even more impractical. It won't retain heat for any length of time (Think how quickely your cup of tea goes cold) and it will take a lot of time and effort to empty, refill and shift enough water to make any difference. Not to mention the cost of heating the water.
I think the best solution is plain and simple fleece, duvets, loft insulation etc.