Tankless water heaters?

Any suggestions on tankless water heaters? are they more efficient? do they last? of course all of the information on the net says so so it must be true Seriously, anyone have any experience with these?

I'm looking at the Aquastar 125HX for use with LP gas to replace a 40 gallon hot water heater.

Is it hard to install? I have relplace basic hot water heaters before and would feal pretty good about replacing my existing on my own but the venting on the tankless seems different. Is it all that difficult to install the venting required?

Brian

Not sure about the LP model, but the Aquastar 125NG requires (a) a 3/4" gas supply line and (b) a 5" flue pipe all the way through the roof. These make it a more difficult process than installing a conventional replacement. They are of course more energy efficient; but with the added install costs, the payback will be many years. The 125 has a rating of 2.5 gallon per minute at 90 degree rise. That is enough for a shower or wasing machine or dishwasher, but never 2 of these at the same time. You may want to evaluate you usage and see if you need to step up to the model 240. If you have hard water, you may have to delime the heat exchanger periodically.

Rinnai

I had a Rinnai 2532FFU installed several months ago. It is rated 8.5 gpm, enough to handle several usages simultaneously. Mine is LP gas. Although its capacity is enough to supply whole-house usage, mine is installed to serve the three bathrooms which are so far from the main water heater that it takes forever for the water to get hot! The Rinnai works flawlessly, but it is more expensive than others I have seen on the market. Nevertheless, I went with this one and I am happy I did so.