I have a single story condominium where the hot water supply to the bathroom sink and shower takes a very long time to arrive. I partially solved this problem by installing a 2 1/2 gallon 120 V instant water heater under the bathroom sink. I ran the hot-water supply under the sink to the cold water input on the instant heater and ran the output side of the instant heater to the sink hot water faucet. That works fine, but I still have to run a lot of "hot" water to the adjacent shower until it is warm enough to use.
I have another thought as to how I might increase or hasten the supply of hot water to the shower. Is there a problem if I supply the instant water heater with the cold water line, using a T, that now runs to the sink. Then Install a T on the hot water output from the instant heater and run one line to the sink and the other back to the hot water supply line from the conventional water heater. That way the instant hot water heater would be hooked to the line that also supplies hot water to the shower. Would this create a problem since the hot water piping in the condominium would now be supplied by the conventional water heater and by the instant water heater?
Richard Walton

Hi Richard,
Instead of running all those lines why not simply locate the hot water supply that supplies the entire bathroom and cut the heater into that? Your thoughts? Tom