Tankless water heater - Has anyone had a GOOD experience?

Question

I have researched them and found most users are dissapointed with their performance (esp during low-flow applications) and that when they stop working (often) it is difficult to impossible to get any service.

The only advice I got was to get an expensive Japanese brand (ie Takagi) and spend the $$ up front rather than on the back end with repairs and replacements.

Surely there are some tankless users out there that have had positive experiences...??

I don't have gas or propane, only electric

Answer 1

See the very bottom for the EDIT on electric
I install these units and have for years. YES, there are some really good ones, as well as the crappy ones. Answer up front, spend the money, it's worth it. Takagi is a good one, i install Rinnai, also very good. The japanese invented and perfected this technology, so it makes sense to get a japanese model.
The smartest thing to do with tankless water heaters is to get someone who knows them well to install them. You can get a list of local plumbers who are Rinnai certified at their website, www.foreverhotwater.com or www.Rinnai.com, I dont know if Takagi has this same feature on their website, but they problably do. There are more technical factors that go into a tankless water heater than any other type of heater/plumbing fixture, so it's wise to have a trained professional do the layout. In some cases i have not been able to install these units in a customers home who wanted one because it would be too cost prohibitive. Below i will address some technical aspects if you're interested in those.
To address the specific concerns you mentioned in your post; some models will not activate (turn on to heat the water) without a minimum flow rate of half a gallon a minute ( .5 GPM, notice that is POINT 5). That's actually a GOOD thing because if the unit activates to start heating the water, and there is very little water in the heat exchanger ( small copper box the water travels through that gets heated externally by gas-fed flames ) it will damage the heat exchanger causing leaking (a very bad thing). Just imagine how a radiator in your car works, run low on coolant and what happens? Overheating, and engine damage. Another factor that can lead to disappointing performance is the type of water feeding the house. (i.e. city/municipal, or well water) with well water, you will only have so much water pressure, ( about 40-60 psi). Municipal water can vary greatly, but if it's coming in too low, say around 25-50 psi (pound per square inch) the desired output of hot water will not typically be realized because there isnt enough coming in to supply the demand. The pressure can also be too high (most codes set the limit @ 80psi) I'd say anything over 100psi can be damaging to the tankless unit, and all plumbing fixtures for that matter.
Besides incoming pressure, the type/size of water pipe is important. MOST homes are sized correctly when built, some are not. But if you have 60yr old rusty, galvanized steel water pipes, youre in for trouble, as that junk can flow up into your tankless unit, and other fixtures and cause problems.
The other big factor is gas supply, there needs to be a certain amount of gas pressure going to the unit to feed it properly. Some homes are 2pound gas systems others are half pound, (natural gas, propane is a bit different). But no matter which gas system you have, the pipes have to be sized sufficienttly if that unit is gonna work right. For example if you have a furnace (or two) a fireplace, a gas stove, a gas dryer and a pool heater on the same gas system, chances are good that a tankless water heater will starve itself (or the other units) when it activates to heat the water. (this can also cause low hot water output as well as damage to the unit) All this is calculated with chart, using BTU comsumtion, pipe size, poundage of the system and distance to the different units. Although its not overly complicated, it's not exactly simple.
THE PROBLEM:
The problem I see in most cases is that the technician (or do-it-yourselfer) who installs a tankless system has not calculated these factors properly (if at all). He/She sees a gas line, an electrical outlet and two water pipes (usually where the old water heater sat) and figures "hey!, im good to go" and starts hookin stuff up. Big mistake. This stuff isn't rocket science, but its not for the untrained person either. As the popularity of these units grows, so does the demand. The labor force however, is woe-fully behind on training to keep up with that demand, thus many improperly installed, malfunctioning units are floating around out there ruining the good reputation of a really great product. Half of my own crew is unfamiliar with how to install them (and consequently they DONT).
Now as for satisfied users, All of my customers have been satisfied with their units, HUNDREDS of them. IF it is installed correctly, it WILL do everything it claims to do. But up front cost for retrofitting (replacing from tank-type heater) is not cheap. In most cases it runs around 4000 dollars (check your local contractors bids of course as prices vary greatly with location) Just avoid hiring someone who doesn't know how to calculate all these factors and you will be fine, and satisified.
Hope this helps
V.C.

EDIT: electric units typically are not well suited for heating whole house water demand. Most brands are great for one MAYBE two fixtures at a time (i.e. one faucet and one shower). There do exist a few electric tankless that are supposed to supply whole house demand but in my years of experience they usually suck. What you have to look at is the demand (how many showers in the home, kitchens etc.) and compare it with the supply. If a tankless water heater, electric, can only give 4.5GPM your outta luck, cuz four and a half gallons of hot water a minute is only gonna supply two faucets at once. In fact most faucets are rated at 2.5 GPMs so not even that (since 2.5 + 2.5 = 5) <-- see my higher math skills ;) So unless you like waiting for your spouse to get out of the shower before you can do dishes, id go with gas. In many cases if you have a natural gas supply in your municipality, the gas company will come hook up a meter to your house for FREE!! Its the ONLY way they get new customers in pre-existing homes. Gas is def. the way to go. You can also do propane.

Answer 2

A tankless heater if performed effectively will paintings simply quality. We truthfully lived in a condo in New Orleans within the 1940's and 1950's that had one and it served us very good. They have turn out to be a lot larger now.