Stacyneil, have you ever tried setting your thermostat say around 90 or higher to see if the floor would get toasty? When I had my thermostat set around 80, the floor would be around 68 - 70. The only reason I have it at 104 was to see if it would get any warmer. When I checked a few other tiles this morning, that are not under the floor warmer, they are around 63, so it is working.

"using an infrared temperature gauge"

Unless you have calibrated for the emissivity of the target the temperature can be off significantly.

toyug, under these cables, is there a concrete slab or a wood subfloor? This makes a difference.

Davidro1, It is a wood subfloor....

in the 8 x 8 space, was it 220-230V, or 110-115V, and were the cables spaced close together or far apart? There are (I think) only two spacing distances as options, for 220v and for 110v systems. I'm trying to get from you enough information to figure out the power, in Wattage or BTU. This makes a difference. Power makes a difference. It's all a power game. Apply power, get warmth. Orient it more of that warmth into the tiles than into the surroundings. End of story.

FWIW, I set mine at 80 and leave it there. It doesn' go on and off. It is nice and warm, but not very, very warm. If I set it at 104, the bathroom would get too warm to be comfortable. When I close the bathroom door, the heat can really build up.

Davidro1, it is a 120 volt system. Regarding the spacing of the cables, the Nuheat system is a mat system so I'm not sure what the spacing between the cables are.

Dedtired, that's what I was hoping for when I had the system installed, set it at 80 and forget it. Does it warm the room, not really... When I had the floor set at 104, the room was at 72. We rented a house in Stowe, VT last fall and the bathroom had heated foors and we experienced the same as you did. We set the floor at 80 and it was really nice. If we moved the thermostat to say 85 - 90, it got very warm in the bathroom. Our contractor and electrician are coming back tomorrow. I'll have to see what they say.

How many watts was installed? They will know.

It's all a power game. Apply power, get warmth. Orient that warmth more into the tiles than into the surroundings. Either you have a small wattage, or you have heat going into the building in general, without it going as much into the tiled floor as you would like. The electricity consumed generates heat. Whether it gets into the tiles is one question, and whether it is a bit undersized is another question.

Just to confirm one other point: in your first post, did you write that you have left it on for days without stopping? Continuously on. ( Y / N ? )

Davidrol, I don't have many answers for you. I'm trying to get the information from my contractor as I don't have the exact part numbers of the mats that were installed. I know two mats were installed, one of the mats is 5 foot by 3 foot and the other one is 2 ft by 4 ft setup in a "T" fashion.

According to the phone conversation I had with my contractor today, the floor system is a "floor warmer", not a "radiant heat" system. I'm still not 100 % convinced of that as I went out to the Nuheat website and they are called Radiant Heat systems, not floor warmers!!

Regarding your last question, yes I had the thermostat set to 104 degrees to make sure it wouldn't shut off and I left it set that way for 2 days and it never shut off, so "Yes", it was continuously on. Hopefully, I'll have more information soon....

Is the floor insulated on the other side?

We have in-floor, hot water, radiant heat in our bathroom and kitchen (not really the same as what you are talking about, I know). But, we are renovating the kitchen and the space underneath the heated floor is only partially insulated (using 2" rigid polyurethane sheets).

I can definitely feel the difference between the insulated an uninsulated areas.

Hot air rises but heat conducts and radiates in all directions unless there is something to stop it.

Your GC is trying to lower expectations by renaming it something else. Not to worry. You will get to the bottom of this.

sandn gave you the best additional input I could have imagined:
"....heat conducts and radiates in all directions unless there is something to stop it....."
"....Hot air rises but heat ...."
+ ".... We have ... radiant heat ... and the space underneath... is only partially insulated .... I can definitely feel the difference between the insulated an uninsulated areas. ...."

This is the first time in all of recorded history that a real user has posted to confirm what I have written often: that insulation IS a factor, and that any and all heat applied is a source of warmth that can make a big difference, or be a disappointment.

toyug, now is as good a time as any for you to write out what is underneath the wood subfloor of your remodeled 8 x 8 bathroom. It makes a difference.

Wow--sandn might have hit the nail on the head with regards to insulated vs not. DH and I suspect the same "issue" with our MB floor--there is a noticeable difference in warmth, aka, toastiness (!) from one section of the floor to another, especially as the weather got colder (not as noticeable through the fall or early weeks of winter). When he gets a chance, DH plans to look into it, perhaps opening up the ceiling in the garage below and adding some add'l insulation where it might be lacking.

The "colder" area is still much, much warmer than it would have been had we not had our Nu-Heat, it's just noticeable when stepping from the warmer part to the less warm, and we would of course prefer not to have that.

Got some info from our GC today. The Nu-Heat mats are Model # F1006. They are 120V, watts are 90, and amps are 0.8. We have two of these mats installed, each 40 x 27. The bathroom does not have any "under the floor" insulation because it is over our cellar directly over our furnance. This area is mostly upper 50's to near 60 degrees. I am able to touch the wooden sub floor from the cellar and it does not feel warm to the touch at all so I don't "think" I'm losing heat from the bottom. Another thing I noticed is that if I put my hand about an inch above the tile floor, I really don't feel any heat radiating from the floor, should I? Also, if I put my hand on the floor it definitely feels warmer than a "non-heated" tile say from behind the toilet. Maybe I'm just expecting too much from this system. I plan to give Nu-Heat support a call within the next day or so and ask them what should I expect from their system.

OK... Here's the problem I see. I have NuHeat mats in my house, albeit concrete floors. I have mats in my bathroom and kitchen. I just checked, and both of my mats are sized (from NuHeat) for 12Watts/SF.

From what you've said, you have (2) 90 Watt mats. Now, you've said a couple of different things in regards to size. First, for an 8'x8' bathroom (64 SF), you should have 768 Watts, not 180 Watts. Second, you stated you had a 3'x5' and 2'x4' mat (23 SF). For this you should have 276 Watts. Then you stated you had (2) 40" x 27" (15 SF). This matches the 180 Watts. To me, it looks like your mats are WAY smaller than they should be to heat the amount of area in your bathroom.

Not an expert, just my opinions.

HTH,
Shane

countryboyok1 nailed it.

Your wattage is lower than you might have wanted to install, if you had given this more thought in advance.
Some people have more watts in their light bulbs than you have in your floor heat.

If you cook something at a low temperature, it will take a long time, and it will feel lukewarm.

Your floor is lukewarm.

Putting your hand on the floor "it definitely feels warmer than a non-heated tile".
This is normal.
It shows you that you do feel some warmth.

Behind the toilet are non-heated tiles, and they feel cold.
Their real temperature is room temperature, but the feel is cold, and this is a normal thing.

There is nothing inexplicable happening.
You have a certain amount of power (watts) and not more.

All the posts from all the other people have been helpful too.
They all explained the same thing.

Hth.

I want to thank everyone for all of your help, I think you are all correct. I was expecting way too much out of these floor mats. The reason they are sized the way they are is because that was the only open area we had in the bathroom. One side is all cabinets/sink and the other side is a small walk in shower and a toilet. The area in between is where we put the mats in. I guess "lukewarm" is better than "ice cold"!! Thanks again for setting me straight..... Jim