I'm currently planning to install radiant floor heat in our master bathroom. But as I was doing some planning I ran into a dilemma. About half of our master bathroom runs over the garage. Because of this, the tile floor is quite cold in the winter (hence the constant request by the wife to install heated floors).
Not only is the entire floor pretty cold, but the part that goes over the garage is really cold. I'd guess there is a difference of 15-20 degrees in the surface of the tile. This got me concerned about the placement of the floor sensor. If I put the floor sensor on the colder part of the floor then the other half will run too hot. If I put the sensor on the less-cold side of the floor, the colder side will not be warm enough. Does that make sense? Do people install "zoned" radiant heat floors and is that the only way around the problem?
I'll presume that you're installing an electric systemfor now.
If you don't already have the system, you should get the one that is just a cable on a spool, not the cable integral with a roll-out mat. Then install it using 3" spacing over the garage and 4" spacing elsewhere. Then install the sensor in-between the element in the 4" spaced area. This will give you 20% more watts psf where it's needed, over the garage.
If you place the sensor in the 3" area, it will shut the system off before the 4" area is sufficiently heated.