I've lived with a tankless for 12 years and would never go back. You get an endless supply of hot water. Endless. For folks with ginormous bathtubs, that's a big bonus. I have a smaller unit, as it's just 2 of us, and because the temperature of the groundwater fluctuates, we have to set the flow rate to a bit less in the winter so as to get more heat from it. But, that reduced flow rate is still more than enough to satisfy a 2.5 GPM showerhead, especially if you make the mental adjustment necessary to understand that you're heating the water up to just above what a comfortable shower would be and barely using any cold water to temper it. That's the biggest mistake those folks new to tankless make. They want the water to be the same temperature as a tanked heater, when it's totally not necessary. Traditional water heaters are set at a much higher temperature so that users will temper the hot water with cold water and thus the tanked supply will last longer under use. For new construction, it'd be an no brainer for me. I'd choose tankless all the way. It is a LOT more difficult to retrofit, because the flue size is larger, and needs to be stainless. The gas piping also has to be sized correctly, and that usually involves a dedicated 3/4" line. That's why the folks that are not in love with tankless will raise objections about cost. In a retrofit situation, where someone has to pay for the labor and materials rather than DIY, it's probably going to take a long time to pay for the cost difference. In new construction, where nothing yet exists that has to be modified, I'd be surprised if the additional materials and labor costs approached $500 even. And, many many municipalities are offering tax credits for the installation of tankless, so it may not even cost any additional on the front end. Another big bonus to the tankless is the size of the unit. Ours is about the size of a suitcase hung on a wall. Compared to a 75 gallon water heater, that's a lot of room saved in our laundry room. If you live in a temperate climate, they can even be sited outdoors and still be fairly non obtrusive. The energy savings are real. Although we're a family of just 2, we saved approximately $35 a month over the old water heater. Sometimes, in the summer, our gas bill is only the minimum charge necessary from the utility. That's $9. And, we use a LOT more hot water in the summer than we do the winter because of outdoor activities making us hot and sweaty. I love being able to jump into the shower and not have to worry about leaving enough hot water for hubby and the 3 loads of laundry that I need to do.

There are minerals and traces of other chemicals in your water. When the water is heated, they get together with any exposed metal in your tank and form precipitates. These are solid paricles which fall to the bottom of the heater, where the burner is. As they collect, they form a layer across the bottom. This layer becomes thicker over the years. By the time you start to notice hot water shortages, this layer is probably a good five to ten inches thick. The higher you turn the temperature, the faster the precipitate forms. The anode rod is a sacrificial piece of metal which dissolves more readily than the steel tank. It lasts around three years. Your hw tank is lined with glass. But the seam on the side of the tank is welded after the tank is lined, and so the glass melts. So, to make the heater last a long time, drain it once in a while, change the anode rod once in a while, and keep the temperature low. There are only three manufacturers of residential water heaters in the US: Rheem, State, and A.O.Smith. All others have contracts with these manufacturers. Read the fine print on the label on the water heater. They have all been in business for a long time. If one is worse than another, it won't stay that way for long, because it will lose business. State has a patent on a special fill tube that circulates the water and keeps precipitate in suspension, but big bucks. State has sued other manufacturers for infringement and won. Otherwise, as far as I know, they are all pretty much the same.

If you go with any sort of solar system, make sure it has a gas backup and not electric. My energy costs went up $100/month when I added our solar system down here in San Diego. I am now getting it corrected with the installation of a small gas tankless unit, using the solar storage system as a pre-heater. If you're building the home then many of the traditional drawbacks of tankless don't apply to you. You can build in the correct gas line and venting from the start. If I were in your shoes I'd probably go tankless (30 percent tax credit this year -- see the stimulus law or visit www.energystar.gov). If a single unit won't handle your demand then get two. And plumb it with the small tank system (10 gallon) for recirculation and to overcome any sandwich problems. This approach has been detailed in this forum somewhere.

Richmond water heaters are manufactured by Rheem and labeled Richmond for the hardware chains. However many times such as gas they may be de-rated, fired at 32,000 BTU's instead of 40,000 that are labeled Rheem and sold through plumbing distribution. This difference reduces recovery rate and first hour availability. Regarding the electrics, components are basically the same, but the insulation factors of the tank and perhaps warranties may be less.