anyone have a tankless hot water heater? "pressure" vs. "temperature"...
Yes, we have an electric one by Titan. I'm not sure if you got the right capacity for your needs, and if the ability of a gas-fired demand heater is as responsive as electric, as it cycles on & off.
Here's our experience: we have a fairly high capacity one, perhaps more than our ordinary daily requirements. It claims to support 2 showers, plus a dishwasher, clothes washer, and in our case, 3 sinks. Not that we'd have everything going at once, but the 2 showers, or a shower simultaneously with an appliance or sink certainly happens. And that's one way they rate these things, so homeowners can get a rough idea of what heating capacity they need.
So we always have lots of hot water for as long as we want, even at fairly high flow rates, like filling a tub. In fact, it's better than a typical 40-gallon water heater tank, which as you know can run out hot water after a while.
But what can happen is an opposite problem -- too slow a flow rate making the unit turn off, and getting cold water. Tankless units must be able to do that, sensing the flow rate through them and turning off below a certain amount. Otherwise if the water going through them slows down too much there's a risk of scalding, and even explosive steam pressure build-up.
It happens to me (but not my partner) because I like to use a minimum amount of water flow in the shower, and also take a fairly cool shower, so the hot water blend I'm using at the tap is very low. Everything will be fine when suddenly -- ICE WATER! I've learned to keep a certain water rate setting, and then I'm OK. The other thing I've noticed for showers is the temperature tends to "hunt" around a little bit at first before it stabilizes, and then it's fine.
Other than we like it, and it does save us money.