Adding radiant heating to basement bath. Need advice.

[ingeborgdot]

I am adding warmwire to my basement bathroom tile floor. Do you really think I need any insulation under it? I understand something like easymat would only help but do I really need it?

[Bill Arden]

This might be better in the HVac section.

Adding insulation is a must if you intend to actually heat the room with the floor.

Without adding insulation the wires will just warm the floor so it's not cold to the touch.

on the other hand you have to be careful when adding insulation since that could cause hot spots.

[jadnashua]

Heat will move to any area that is colder. Yes, in free air, the hotter air will rise, but it will conduct easily in any direction. The ground is a great heat sink and can suck much of the heat away - it can be expensive to heat the soild under your slab. There are a copule of things that might work for insulation, the EasyMat you mentioned and possibly Wediboard. It's a tileable foam panel, available in various thicknesses. You'd want to check with the manufacturers of each product to see how they feel about electric heat on them.

[PEW]

I have used Wediboard for electric heat on concrete floors with good results.

Keep in mind that the amount of heat available will be dictated by the available space for the wire. If you have a small area, the amount of heat generated will be minimal, but will eliminate "cold feet".

[ingeborgdot]

That is my goal entirely. Eliminate the cold tile feel. If it works and heats the room great but I don't like cold feet. I have talked to several people around the area that have done nothing under the warmwire and have had great results. I have decided to not mess with the cork or whatever it is and do what they have done. I will let you know if that was a mistake or not.

[PEW]

It will cost you more to operate, with less results. With rising energy costs, I would not do it without some type of insulation.

Would also strongly recommend a thermostat with an under floor sensor.