Out of those 3 brands, I would suggest Noritz. You may also want to consider a hybrid water heater. Here is a link that might be useful: Our Site

The next question is what kind of tile? If the water heater is installed in an attic or over a wood floor you are required to have a pan with a 3/4" diameter drain line to an approved indirect waste receptor or outdoors in a conspicuous place. If it is installed over a floor that is not subject to water damage, such as concrete or ceramic tile it does not require a pan. All water heaters are also required to have a TPRV (Temperature & pressure relief valve) with a full bore drain line to an approved indirect waste receptor or outdoors EXCEPT: in instances where a gravity flow drain line cannot be achieved, such as below grade in a basement, the TPRV may be removed and if it is a gas water heater a "Watts 210 gas valve" is installed, then the gas supply line is run to the Waats 210 gas valve, then to the water heater gas control. In this manner if the temperature in the tank exceeds 210degF or if the pressure exceeds 150psi the Watts 210 gas valve closes and shuts off the gas supply to the burner. When a Watts 210 gas valve is installed you must also go to any convenient location in the structure and install a Pressure Relief Valve on the hot water system where the Pressure Relief Valve can be drained to an approved indirect waste receptor or outdoors. In the case of an electric water heater you only need the pressure relief valve because the upper thermostat in an electric water heater has the required thermal shutdown function.

Tankless are quite a bit more expensive to buy, so my guess is that they are still not popular for mid-priced homes. Most folks are stretched thin when buying a new house, and visible improvements (bigger rooms, nice kitchens and baths, etc.) usually take priority over highly efficient plumbing and heating systems. With a new home they should be able to design the house to work well with a tankless, and it should work better than most retrofits. However, tankless still requires a lot of gas or electric power when running (requires bigger gas line or high amp panel), and the entire household has to adjust water use habits (turn on full to activate, and wait for slug of cold water to clear, etc.). Some folks just like the traditional solution better. Bruce

I understand. People who have had this problem - esp when the heater is on the main floor (rather than the basement) -- are often very paranoid about a recurrence. I've installed Rheem tankless units in my last couple of homes and have been very happy with the brand. You should understand that a gas tankless heater will be expensive to retrofit. They may have to run larger gas line and will have to install a new flue (as well as an electrical outlet.) Again, keep in mind the Rheem Marathon fiberglass tank water heaters. They only come in standard electric - but could be an alternative to a gas tankless. To answer your question about the drain - a condensing gas tankless requires a drain. It is my understanding of code that a water heater T&P valve must be able to discharge without causing significant damage - and thus a drain is always required, regardless of the type of heater. I assume you are grandfathered or have some way around this provision - so I won't argue that point.