The Bosch AquaStar 2700ES tankless hot water heater is similar in many respects to the Bosch Pro 715ES tankless hot water heater.
They are both 199,000 BTU tankless water heaters and they both sit in the same chassis or case - the new "World 2" case.
Both have modulating gas valves and have the same .65 GPM minimum activation rate.
There are a few key differences between the two heaters, though.
One key difference is that the Bosch 2700ES comes with built-in freeze protection. This freeze protection is meant to keep the heater from freezing in locatons that experience occasional overnight freezes. The Bosch Pro 715ES does not come with this freeze protection -- but it is an optional accessory that you can pay extra for.
Another difference between these two heaters is the water filter.
In the Bosch 2700ES tankless hot water heater the water filter comes with the heater and is very easily accessible without having to even remove the cover. As you can see from this image, (1) is the water filter.
Bosch recommends that you inspect and clean the water filter once per year as part of your annual maintenance of the heater.
With the Bosch Pro 715ES, the water filter is an optional accessory - albeit a highly recommended accessory!
The Bosch Pro 715ES is a wholesale product that is meant to be sold directly to an installer. It is designed to be professionally installed. As such, it comes with a 15 year warranty. The Bosch 2700ES is a retail product that is meant to be sold directly to home owners and it comes with a 12 year warranty.