Geniescience
Homeowner
Very precise. Thank you! I can agree to use the term "a real sensation of warming" as being produced when the source temp is higher than the target temp.Bob NH said:.... You don't get any real sensation of warming from a floor at 75 degrees F. You get a sensation of warming from a radiant source if the source is at a higher temperature than the target. ....
This definition accounts for the shifting point of reference too!
Your outer shell (skin) is at a certain temperature of reference, lower than the temperature of your internal organs. When you put a finger in warm/lukewarm water, it feels warm, and then not, after seconds -- since your fingers have been warmed up to the water temp. The only way for the water to still feel warm is if its temperature keeps going higher than your skin temperature.
Lee, have no fear. A warm floor feels good. Newbies are often concerned it might go "too high"; I've seen it before, and earlier in this thread, I read that "above 85f" might feel too hot. No. You want to be able to turn the floor heat up to 90f and even 95f whenever you want. It is true that it will feel strange to a first-timer who steps onto it with cold feet, but it won't hurt and once they have walked on it a few times they'll like it. As a test, you could put a large tile in hot bathtub water with a thermometer to measure the water temp and then remove the heated tile and ask people to put their weight on it barefoot and tell you what the sensation is like to them. The more they do it, the more they want it hot. Guaranteed. Whether you start out extra hot and go down in temperature, or low and going up, you'll find that their temperature that defines comfort will keep rising until it meets the definition that Bob has provided -- a higher temperature than their feet, by far.
Installing a heat break membrane under the tiles is the means to achieve the end, so the user can enjoy a floor temperature as high as they want when they want.
Quiz: What is worse than a cold tile floor?
A: A heated tile floor that doesn't warm up enough to make you feel like you got want you wanted after all.
Lee, don't worry about the internal temperature inside the wire either. I read in this thread or another a remark you made about that temperature. The wire is designed to get hot, just like a toaster filament or an oven heating element, so its core temperature is not to be taken into consideration.
David