I have seen underfloor heating ---electric and those with water pipes...

1. Is there a disadvantage to underfloor heating?
2. Since it will be placed underneath ceramic tiles or hardwood which is permanent, will future repair be a problem?
3. Since there is heat, will growth of bacteria of molds be faster?
4. What is the brand/model is the best underfloor heating?

Those with water pipes (hydronic) can get expensive, especially if it's not new construction, being that it's considered a primary heat system, and would have to come off your furnace.

The electtrical systems are only to warm the floor, and for that, they work very well. Some of the better systems are Nuheat, Suntouch, Warmly Yours, and Laticrete's FarenHeat system. All of those are made to be used with tile, but as far as I know, the only one I know for sure makes a system for any other flooring is Warmly Yours, which can be used with engineered wood, Laminates, and carpet. none of them can be used with conventional nail down hardwood, due to the fact that all it would take is one nail or staple thru one of the wires, and the system is trash.

As for the worry about mold, heat isn't what makes mold feel cozy. Moisture is, so that's not a problem.

If repairs are ever necessary (they shouldn't be, once the floor is down, but just in case--), it's usually not that big of a deal to find the problem BEFORE doing anything to the floor, and then keeping the repair localized.

I installed 2 Suntouch Warmwire systems in master bathrooms. They are electric and have programmable thermostats and are very luxurious. The second installation had a problem where the thermostat went bad and kept clicking. We replaced it and it worked fine since. After 3-4 months the customer called and complained that the tiles and grout have hairline cracks in a few places. I'm baffled as to what caused this. I'm trying to get an "expert" from the Tile Warehouse that sold us most of the materials to diagnose the cause and remedy.
The floor is supported by 2X10 joists with 3/4" plywood glued and screwed on top. I added 1/4" Denshield and glued and screwed that down to the subfloor before adding the wire and then Latex modified thinset and travertine tiles. If it weren't for this second installation I'd have highly recommended the warm wire system.

I have to say I love my Warmwire almost 2 years later. I'm near the coast and mold and mildew are huge problems. The warmwire has totally eliminated the mildew issue for me. It's fabulous. I hope I never have to repair it, because, wow, that will suck, but so far it's great.

I had a floor heating system put in my bathroom from Warmly Yours. It is a great system and it actually got to the point that I closed the heat vent in the bathroom because of the heat it gave off. They offer a blueprint of how the heat grate should be laid on the floor and some other stuff. Try out their website at www.warmlyyours.com

Handy Rob,
The problem with your second installation is not the radiant heating system. The issue stems from your installation method. Cracks through the tile indicate an insufficient subfloor. Sistering in a few joists or adding a second layer of ply would have probably protected against this sort of failure.
Another mistake which can cause floor failure, with regards to radiant heating systems, is that the system is energized too soon after the tile is installed and the heat compromises the curing of the thinset. How soon after the stone was installed was the floor "test driven"?
Herbolaryo,
Radiant heating systems require patience when being installed and they are expensive, on the front end. But after they've been installed correctly they are protected from being damaged . I always install a second floor sensor in my heating systems as added insurance though. The redundant sensor is left unconnected when the thermostat is installed. In the event of a floor sensor failure, the primary can be discarded and the redundant hooked up in it's place. Follow the manufacturer's installation instructions, including resistance testing during installation, and you shouldn't have any issues.
Best of luck,
Shaughnn

I am building a new home and would like to use the hydronic heat system. There weren't many comments about the disadvantages of this type of system or brands that are considereded the best in the industry. We want to heat the entire first floor with it and there will be a basement below. What are the potential problems for failure in this type of system. I would like to install natural stone over it, possibly some hardwood, not engineered wood, in some areas. Also want to consider solar power to heat the water. Is this possible? What type of heat will I need for basement and second floor? Does anyone have any history, 20-30 years with this type of system? Thank you for any insight that you can provide. I would like to head off any potential problems with installation that could affect us down the road.

Are you talking about hot water baseboard, or radiant water system?

I have seen hot water radiant heat systems in homes over 60 years old. The disadvantage of these systems are few.
Future renovations ofetn are difficult as pipe layouts may interfere with punching holes in floors or walls.
Leaks caused by contractors nailing into floor not knowing this type of system is in home.
Termites often do not go dormant in winter if slab in basement is heated. Be sure to treat before backfill.

Installing this type of system although simple, can be difficult to those who never worked on it before. If the builder does not have experiance be sure he or she understands what is involved.
System must be pressurized while cement pour goes in and stay pressurized until it is fully cured.
If your going to install wood be sure that the contractor properly nails to sleepers set into floor. One goof and your tearing up the floor.

As far as brands. All new systems use PEX tubing. Much better then the old copper used years ago. Other then that the manifolds used should be name brand. Something a local plumbing supply carries parts for. Not big box stores. Real plumbing supply company. The valves and temp controls for the zones are the expensive parts. You want to be sure you can get parts without chasing down the installer who does this for you should the need arise 10 years down the line.

As far as solar to heat the water, Sure why not. Remember you do not have to heat the water as hot as a baseboard system would require. If fact it would cause all types of issues with overheating rooms and discomfort if you did. So Solar would be fine. You would need a large holding storage tank to offset the loss during the night. But with proper wall insulation, and good construction methods the cost of operation will be very litle as compared to baseboard heat.

Real good synopsis, Home Care Club. Can't emphasize enough that this is NOT the place to cut corners and save a few pennies. Buy top-shelf controls and hardware because these weak links can't be repaired cheaply or easily if they fail.
In cold climates I've heard also that it's very important to protect against freezing, though I'm not familiar enough with hydronic heating systems to know the full answer. Can you shed some light on that Home Care?
Shaughnn

The only disadvantage of radiant floor heat that I can think of is thermostat response time. It is not quick, it takes a few hours to move a few degrees. I can think of many advantages that outweigh this disadvantage. We install quite a few of them and in fact, we try to convince people to use them because aside from that one disadvantage, it is a far superior heating system. We just built a 56 x 80 shop and the entire floor is heated with radiant floor heat, the boiler is only about the size of a small suitcase.

Edit: I have priced this system with the solar panel option for a customer once but it was quickly dismissed once we learned the cost. The payback simply wasn't there, and these are very environmentally conscience people. I believe it added something like $25,000 to the pricetag, for 320 square feet of solar panels...ouch.