I need to replace my old 40 gal. propane water heater and would like to know if anyone has any exper. with the tankless type. I have a duplex and will be running 2 households on 1 system [ 2 showers, 2 sinks, 1 washer, and 1 dishwasher] I'm looking at the aqua star 170 and would like to know if it lowered water press. or took a long time to heat, and how it was to install thanks for any reply tom in minn.