Originally Posted by Nestor_Kelebay
Where would be the disadvantage in putting a hole right through the exterior wall of your house so that the water supply line from the heater in the garage to the dish washer would be much shorter?
Also, putting pipe insulation on the water supply pipe between the heater and the dish washer will help tremendously in preventing the hot water from cooling down during the wash cycle.
There would be no advantage to running another line outside the kitchen wall since the dishwasher and heater are at opposite ends of the house. The dishwasher is near the northeast corner of the house and the heater is near the southwest corner of the house. Straight-shot the run is about 120'.
As another alternative, one of the guys at HD suggested the WATTS Hot Water Recirculating Pump. (I would link to it, but the rules forbid it. You can find it by searching "Recirculating" on the Home Depot website.) I'm torn on this product. Cons: it's nearly the price of the small water heaters. It looks cheaply built. Pros: I can install it myself. It has a timer, unlike the water heater. It's cheaper than a new high-end dishwasher.
Any thoughts on the semi-recirculating pump? I guess I should also mention, we nearly don't use cold water, so the delay in cold water wouldn't be an issue.