They're not good for larger homes. You need 2-3 of them and by then the cost savings is eaten up.
Huh? How big is your house, 10000 square feet?
Consumer tankless water heaters go up to 199000 BTU, which is fine for a pretty big house. In Florida it'd handle 3 showers simultaneously probably, or at least 2 plus extra. In Indiana, 2 showers in the winter max.
For a medium or large sized house in Indiana, I'd recommend a 199000 BTU model.
I hate the things. It's always inconsistent heat. For a bath it's fine. But trying to adjust the water flow up or down or turn it on and off they constantly are all over the place with the temperature. Or if someone else does something at the same time, or something else is running. It drives me nuts. And don't say it's the model. They all do it. It's the nature of them trying to adjust and catch up constantly. Maybe most people won't notice as much and think about it but I definitely can tell and it's very bothersome. Plus they are loud as hell. Every time you turn on the water it's Wooooo AHhHHHH WOOOOOOO Ahhhhh Ahhhhh WOOOOOOO. So annoying.
It sounds like you have lower end plumbing fixtures. A good mid-end shower fixture will keep temp constant, even when hot water volume decreases.
With my modern fixtures and my modern 199000 BTU tankless, I never have the above issue.
Regular tank heating is very consistent and quiet. If you have a very big family and use lots of hot water you can daisy chain regular water tank heaters. I doubt you save much money either on energy with tankless. My regular water tank heaters are always electric and in the summer my electric bill is like $20, which means the water heater can't barely be any of that.
Tankless won't save you money. The primary reason to go tankless is to get endless hot water, or else to save space.
In my case I had a 50 gallon tank, but it wouldn't fill up my Kohler 2-person tub. Due to the layout of my utility rooms, I couldn't install a 75 gallon tank, but it was a moot point, since 75-gallon tank heaters with motorized venting cost as much as tankless water heaters anyway.
So, I went tankless. Now I never run out of hot water, for obvious reasons.
That is not to say I wholeheartedly recommend tankless. There are still advantages to tanks:
1) Faster filling (until it runs out).
2) Still have hot water in a power outage. (However, I have my tankless on a battery backup. Mine needs about 40 Watts when running.)
3) Only need to change the anode rod after a few years. No yearly or biyearly chemical flush required like tankless.
4) No
cold water sandwich effect. (However, I don't have that either, because I installed a 6 gallon tank to eliminate the cold water sandwich.)
5) Water reaches fixtures faster by about 10 seconds or so. (However, my 6 gallon tank eliminates this tankless delay.)
6) Probably cheaper than tankless overall, esp. if you can install a non-power-vented model.
Your knowledge seems outdated, or tied to a specific model. If I set my tankless to 120 or 112 degrees, that is exactly what comes out of the tap, regardless of flow or incoming water temp.
Indeed. I've measured mine. I set mine at 125, and it's always about 124 according to my meat thermometer, regardless of the flow rate. I'd say that's within an acceptable margin of error.
In the dead of winter the flow is slower, but it's still fine to have a shower and a dishwasher working at the same time. I'm not sure what the incoming water temp is for the other posters in this thread, but in many areas even in temperate zones, even in winter the water isn't
that cold, because it's ground water. In Toronto where I live the temperature is more of an issue, because the water comes from Lake Ontario, which gets a lot colder in the winter.
But even then, for my big house, the volume is fine in the dead of winter. We don't have 3 showers running though. Two shower works, but at the coldest times of the year I notice there is small decrease in the shower water volume for each shower when two are running simultaneously.
I might decrease the temp to 120 though, because we have a young kid in the house. 120 F is the usual recommended temp for homes, because it takes minutes to scald.