Cork, Wedi, Cerazorb, Acousti-tech, or other pad type underlayment
Bob is right about many things.
I agree with his conclusions 99.9% of the time.
We may find after a long discussion that I also might agree on the one thing that I cannot lend my support to here. Or he may have been attempting to drive home a point, and using a strongly worded conclusion to do so.
Skin temperature is always lower than body temperature.
When discussing heat transfer between two objects,
we could use the strictest definition of heat which means we ignore skin temperature and always refer back to body temperature. However, people only feel heat on their skin. (More later about this. To be continued). When someone's skin temperature gets raised by a new heat source, that immediately creates a new point of reference.
So skin temperature is a
moving target and that fact alone makes any discussion of "feeling heat"
extremely complex. Phew!
Repeat: once your cold winter feet get warmed up by the tiles, they won't feel so warm anymore. The tiles I mean won't feel so warm any more.
Furthermore, the net heat transfer will still be in the opposite direction. I mean away from your body. You will be losing heat to the tiles. (More later. See below, about ocean water). Bob mentioned the rate of heat transfer; tiles are a good heat conductor. This is a crucial part of the analysis.
To complicate things even more, I'll say this: that
the psychological feeling of warmth (heat) going towards/into or away/out of the body does not depend on object/skin temperatures, and also not on the rate/speed of heat loss, but on the comparable heat loss rate
-- with other surfaces nearby! Comparable in one's immediate physical memory. Phew!
Phew!
It is true that tile (porcelain or ceramic) will pull heat away from your skin.
It is true that tile (porcelain or ceramic) will pull heat away from your body (and thus skin), even when the tile is heated -- except initially when your feet are cold. After your feet get warmed up, the tile floor is still cooler than your body temperature. The RATE of heat flowing away from your body is much lower when the tiles are heated, and this makes the tile surface feel warm, to some, and not warm to others.
A heated tile floor, when built on an insulating underlayment like cork or synthetic membrane, will produce enough heat to feel really warm to anyone whose house is surrounded by cold radiating in from the outside. At first, your cold feet will be warmed up. Later, when your feet are warmer, the heat loss (from warmed feet to tile) will be less than the heat loss from feet to wood floor -- assuming you have a wood floor in the rest of the house. This is what I meant when I mentioned "comparable surfaces nearby".
I think a heated floor will also feel warm to anyone in a warm climate too. When direct sun is shining on it you can still notice the difference but it's no longer as significant; the sun is the strongest heat radiator we have.
A comparable phenomenon I think is this
- A.) hypothermia in warm ocean water, versus hypothermia in water that "feels cold" to start with. Staying for hours
in warm water will suck heat energy out of your body.
- B.) Feeling, and enjoying feeling, warm ocean water, versus feeling water that "feels cold" to start with -- and not enjoying the sensation.
Part A.) is reality, regardless of feelings, and Part B.) is all about feelings, sensations. Both waters, warm and cold, are below body temperatre, and yes they both remove heat energy from you. One feels warm; the other feels cold. For how long does the warm ocean feel warm?? Everyone can have a different answer, since it depends on one's point of comparison.
Conclusion: three things to do: use an insulating membrane, use an insulating membrane, and use an insulating membrane. Then you will have heat so high that even the most sceptical person will appreciate the warmth. Not only will it feel warm at the first second, and the second second, and so on for many seconds, but also AFTER it warms your feet up, it will still feel warm to your senses.
Many people feel frustrated when the heated tile floor only seems to work for a short time while before it feels cold again. Their feet have gotten warmed up to a level that now causes the point-of-reference to change, and the sensation of warmth disappears. That is frustrating. The shifting point of reference.
I believe the most sensitive people are engineers who understand heat transfer. They can feel the differences in heat flow rates (heat loss or transfer), to a finer degree than anyone.
David