In my effort to help keep beating this dead horse, here is a chart comparing different types of water heaters and estimate costs.
Do the installed costs line up?
"Dude, we can fix that. My old man is a TV repairman, he's got the ultimate set of tools!" --Jeff Spicoli
I've done some reading and my guess is that the installed cost is for new construction. Changing out a tank heater for a tankless can get much more costly for some. I was looking at the Rinnai tankless to see what it needs for an install. The fact that it is a direct vent is problem for me since it cannot use my existing flue and I cannot change out my existing flue since it is used by my furnace. This means that I would have to find a way add a new vent for this heater. This is where it gets ugly and would probably get expensive. The desired location of the heater puts it in a location where there are too many other things in the way to install a vent for the tankless. If I go with a different manufacturer that has a b-vent tankless, I run into a different problem. My current vent is inadequate and probably half the size that is required to run my furnace and a tankless. Then the question is whether or not I have room in the existing cavities for a larger vent. Also, a b-vent tankless is less efficient at a .70 EF.
I've been keeping my eye on the comments regarding tankless heaters and until now did not look too deep into what it would take for me to convert to a tankless. I now think that a tankless would not be a good fit for me. I should also add that my water is moderately hard at 130ppm and scale build up might be a problem for me that would require more frequent cleaning than once a year.
I'm all for being green, especially when it helps keep the green in my wallet. Converting to a tankless would not be cost effective for me though.
You have to install a new vent if you go with what they recommend for a tank type of water heater. Same type of vent problem as the tankless heaters.
Storage Water Heaters
These are by far the most common type of water heater in the U.S. today. Ranging in size from 20 to 80 gallons (or larger) and fueled by electricity, natural gas, propane, or oil, storage water heaters transfer heat from a burner or coil to water in an insulated tank. Because heat is lost through the flue (except in electric models) and through the walls of the storage tank, energy is consumed even when no hot water is being used.
New energy-efficient gas-fired storage water heaters are a good, cost-effective replacement option for your current water heater if you have a gas line in your house. They have higher levels of insulation around the tank and one-way valves where pipes connect to the tank, substantially reducing standby heat loss. Keep an eye out for the price to come down for newer super-efficient "condensing" and "near-condensing" gas water heaters, which save much more energy compared to traditional models but are currently niche products. For safety as well as energy efficiency, fuel-burning water heaters should be installed with sealed combustion ("direct-vented" or "power-vented). Sealed combustion means that outside air is brought in directly to the water heater and exhaust gases are vented directly outside, keeping combustion totally separate from the house air.
Good all around summary of various water heating methods. Note that they did not consider actual lifespan in their calculations.
4. Currently, there is too little data to accurately estimate life expectancy for tankless water heaters, but priliminary data shows that tankless water heaters could last up to 20 years. For all water heaters, life expectancy will depend on local variables suck as water chemistry and homeowner maintenance.
I think it would be great if a tankless were a more viable option, but it is not an economical option for me. It would have been nice to get a bit more space and lower gas bills.
I don't see anything in the newer models to suggest that they will last any longer than the Aquastar and Paloma Pak units. Most of them made it around 10 years.
... market survey???
I know of two E.L.M. Aquastar (pre-Bosch takeover) that are still in service with 15+ years on 'em. Don't know of any that out & out died or needed a heat exchanger swap, but it's a pretty small sample size (and only one can I claim the installation on.) They're somewhat finicky PITA units with mechanical feedback that doesn't really modulate well, with a propensity for overheating then self-extinguishing at low flow, but they just won't die (as much as the current owner of one wishes it would. :-) ) I think of them as "reliably finicky". :-) Maybe I live/work in an area with fewer water-harness issues or something(?).
But the newer versions have both much higher efficiency and higher complexity. Their true track record is still being made, but the Rinnais & Takagis I've encounterd over the past 5 years all seem to be in good shape and running without problems. (I understand that some people have run into issues with Takagi flame-detectors, but I've yet to see it in person- perhaps I will some day...) Again- a relatively small sample-size.
I've yet to encounter anybody who replaced their tankless with a tank (except a few of instances where they were upgrading heating system boilers and went with an indirect-fired tank, which is the best of both worlds IMHO.) Have you?
I've read of people who had been using them as hydronic boilers trading up for mod-cons though.
They may not be for everyone, may not be cost-effective in low-cost fuel markets, but people don't seem to trade 'em in, and live with 'em despite their quirks. Hard-core greenies seem enamored of the operational efficiency, but that wouldn't describe the average tankless owner in my neck of the woods.
Market survey? He don't need to do no stinkin market survey.
I have the second build of the ELM Aquastar 125 VP. The mechanical feedback modulates well if you calibrate it properly and set the water temperature to about 125 degrees. You have to make sure that low BTU is indeed low. My unit was calibrated a bit on the high side.
All the important parts are still available on line for repair purposes, so who knows how long it will last. Then again, I am not sure if a plumber can handle a simple repair job without a song and a dance about something!
I guess I base it on the pile of dead ones that I keep upstairs in the shop so we can rob parts off them for the few that did make it past 10 years. I spose I could take a walk up there and count but I know it's better than 25 and if I add in Paloma Paks its probably in the 35 to 40 range.
Do you think we just make this stuff up for the fun of it.? we are in business to SELL products and make money. If a product is viable and we can make money on it then we gladly sell it.
I hate to say ...... I told you so....
Anything that has more than a 3-5 year payback on a house is not worth it! Going green may be a good idea but until it becomes affordable, it doesn't make sense. Thanks for proving what I've been trying to tell people all this time!
It's not "new" though...it's over a year old.