[Hakkaboy]

OK since I've had mine for almost 6 months now, I'll comment:

Ours was a gas condensing unit and required new venting outside to our roof, which required strata approval for our townhouse.

It(Rinnai RUR199in) has all the bells and whistles including a re-circulation pump that I could schedule (on my phone) when I want the pump to work and pre-heat the water, sort to speak.

When I use hot water during the pump schedule, it comes on almost in the same time as regular hot water tank. When it is outside the schedule, it will be slower and noticeably so. It is even slower than units without a re-circulation feature. Sometimes, it does not even come on at all. I think this is due to some of my faucets being "green", so it does not meet the minimum flow rate for turning on the tankless unit.

In times like that, I have to reach into my phone and press the "recirculation" button on the app. Or I turn on a faucet that I know that will turn it on instantly (i.e. my bathroom faucet that's closest to unit). Some people recommend scheduling the hours you will be at home, but we just keep it on in the mornings for when we know we will be taking a shower.

As for efficiency, I can not speak to it as we installed it before moving in. From looking at my hydro bill, it does seem lower than "comparable homes nearby", but unfortunately it does not list the historical records of the previous owner. I'm not sure if the efficiency will ever justify an extra ~$5K of costs amortized over a 15 year period, so I wouldn't do it for only that reason. My unit has a warranty for 15 years and expected life up to 20, I think. My costs also include some repairs and additional plumbing to our stupid tiny air handler that uses hot water to heat the coils, so your installed cost will probably be less.

We are fortunate to negotiate the cost of the tankless into our offer when we found out the normal tank was leaking during the home inspection, so we essentially got this tankless for free.

Now, the main and only benefit is that I NEVER again have to worry about taking extra long showers, or taking a shower immediately after someone else takes a nice long hot shower. Only YOU can figure out if that's worth the price or not.

Well I guess not having to worry about leaking tanks again is another benefit...