My new house has an outdoor spigot which is supplied by the same copper pipe as my hot water heater. (There's no cut-off valve for the outdoor faucet individually!) Going backwards, the pipe from the outdoors come in just a couple of feet to a T back to the supply and down to the water heater — just a few more feet.
When it's cold — and this is New England, so it gets cold! — that pipe going down to the hot water heater gets very cold to the touch. Much colder than the water source pipe further back inside . Heat is being drawn to the cold outside tap and water going into the water heater is effectively pre-chilled. This can't be good!
The question is: how bad is it? Is this costing me enough that it's worth having a plumber come out soon to just correct this problem, or should I wait until I have some other bigger things going on to put all together?