If you mean tankless being a coil installed in your boiler, then you can go that route, and it should be the cheapest of your choices.

I have used tankless for over 30 years and have never, ever, run out of hot water for a family of 5.

I used 250 gallons of oil per year, consistantly for 30 years for my hot water.

Your hard water might cause a problem with lime build-up in the coil. You might want to add a softener.

Planning on 15 to 30 years in the same house?

No question - Go solar

I installed a 4 X 10 solar collector on my roof about 18 months ago connected to two high efficiency 55 gallon tanks and it provides 100% of our hot water for about 10 months of the year and probably 50 to 75% of it during the other 2 months

Our annual water heating costs are probably down by about 90%

Don

Don, out of curiosity: How much was the cost of the total solar installation and how much were your heating costs before that?

I installed it all and plumbed it myself - Not a really difficult job . . . . maybe 3 on a scale of 5

The collector panel was $1K, the tanks were $600 for the pair, the circulator pump was $100, the differential controller was $200 and about another $300 for copper piping, valves, flowmeter and an analog temp guage. $2200 for the total system, give or take $100. We had no hot water heater to begin with, so we would have had to spend $300 anyway, so take away the $300 and the $400 in Tax rebates and the system actually cost us $1500 - I got $300 off my federal income tax and another $100 from the state

My 'break even point' is about 3 to 4 years - It would be higher if I had paid another $1500 to $2K for a professional installation

We're remodeling an old farmhouse, so we've never lived here with anything but the solar heat but the tag on the side of one of the water heaters says it costs $400 per year to run - It's a very high efficiency unit with 3 inches of polyfoam insulation, so a lesser water heater would cost more to operate. $500 to $600 per year is probably an average cost for domestic water heating per year for a family of four

I REALLY don't understand why there isn't a larger push from the government on solar water heating. Unlike solar electric, or hybrid cars, this technology is pretty well perfected right now and the payback is much shorter than for just about any other 'green' energy source. It can be used in most places in the United States. The outside temp isn't a big factor in how well it works . . . . it depends more on how many sunny days you have

If more houses had solar domestic hot water systems, we could make a huge dent in the total energy use of the country and just think of how much less fossil fuel we would consume

Don

Is your electrical panel up to going tankless electric?

Those things can take a LOT of juice.

Don, that is really a bargain for what you did. I must have been thinking of solar electricity and it's high cost and forever payback time.

I live in PA with a perfect southern exposure but a short "hot" season. What state do you live in?

My choice would be to go with the SuperStor indirect water heater. We install stainless indirects for customers with well water, and stone lined tanks for customers with municipal water.

"I have used tankless for over 30 years and have never, ever, run out of hot water for a family of 5."

baymee, you must have better luck with tankless than most of our fuel customers. We replace countless tankless coils per year since they either don't provide enough hot water, the customer is burning too much fuel or the coils are plugged. Once the tightly wound coil loads up the efficiency drops like a rock.(not that it was good to begin with) People won't flush them with acid anymore due to liability, so they end up replacing them which isn't a cheap job these days with the cost of materials and labor. Some of the older tankless coils with larger coils on tube type boilers used to last quite a while in comparison to the smaller tighter coils in vertical pin style boilers.

95% of all the boilers we sell have tankless coils and that's all the people use. I might pull a coil for an indirect set-up less than 5% of the time. The acid cleaning liability issue must not be in this area, because it's common practice.

THANK YOU so much for everyone's quick responses.

baymee/krame: good point about whether our electrical panel could handle an electric tankless. We just moved into our house in May, and one of the things we have to do in the next few years is to upgrade the electric, so no, our current electric system could not handle an electric tankless.

Since we just moved in (moving/closing costs), and we just spent ~$10K on paving/re-routing our driveway (we're on corner lot, we took some trees down and re-routed to the slower street), we don't have the money to convert to gas.

don: that's a great idea. but we have LOTS of trees shading our house, so I'm not sure solar would work for us. In the next few years, we have to cut down about 7 more trees, but the driveway took priority (safety for my 2 babies).

markjames: thanks for your input which helped reinforced our decision to go w/ the SuperStor indirect water heater.
We're in MA. Is $1700 INSTALLED a good quote for a SuperStor 45gal tank? Apparently the ?flow rate is like 140gal/1st hour? or something like that. I'm concerned about 10years down the road when my 2 babies are now hogging the bathroom and we run out of hot water.
- can you also help with what to do about HARD well water? We have a Culligan unit (I think it's a filter and not a softener). We never had well before, so all this is new and the learning curve is steep.

thanks so much.