I also have a Bosch 250sx tankless
I agree with edumacated on his facts and opinions. I set the temp on exactly what I need at the shower, and leave it there. About 114-118 is what I need at the shower, and I rarely change it. I do not have the remote option, but it seemed interesting. I think Bosch does offer the remote, and other brands (Takagi etc.) do.
Mine has been in operation for about 4 months, and I have seen a noticable decline in costs so far, but with the variable weather factors it is hard to pinpoint the exact cause: sufice to say that my heating bill from Dec-March has gone from $16 per day down to $8-10 per day. I figure I am saving $50-80 a month, vs. the 75 gallon RO Smith tank HWH I had before.
That said, purchase/install cost was about $400 more than a comparible propane/ng tank heater, but the installation was much more involved, since I had to go from a standard vent to a dual intake/exhaust vent. I did the reroute of the gas supply, plumbing etc. myself, and it took me about 2 weeks to complete, doing a 1-2 hours a day (I am slow and methodical). However, i did do the install while the old one was still working (it was leaking), so the plumbing was a bit more involved. Also, I had to bore two holes in the brick wall, another pain I was not prepared for, but easier than expected. That cost about $100 in rental fees for a bore hammer/drill, so I figure my DIY install job at about $200 total.
The cost savings is two fold: the obvious is that you dont have heat loss from the tanks to the surrounding air and up the chimmny. The second is that normal house heat is also going up the chimmny, but I dont know how to quantify that. My savings also might be higher than most, as I have a large house (6000 sqr. feet), and I had a large tank at 75 gals. Although I feel I am saving more than $50 a month, I think $20-30 might be more realistic. My initial calcs at payback were 3 years vs. tank, but I might be ahead of schedule.
Re: I also have a Bosch 250sx tankless
Your calculations are legitimate IF the instanteous heater lasts. The ones I have run across haven't lasted, their service life is less than a conventional hot water heater. Time will tell I suppose.
Originally posted by dogturd
.......Although I feel I am saving more than $50 a month, I think $20-30 might be more realistic. My initial calcs at payback were 3 years vs. tank, but I might be ahead of schedule.