Again - lack of specific details on subject.
1st: Demand systems VS Return Loop systems. My impression is that "demand" type system creates a "cross connection" (however short the time period) thereby introducing the possibility of drinking water from your hot water tank. NOT a good thing! Am I way off base here?
The "loop" systems downside seems to be wasting a lot of resources & money to keep the loop hot. Can this be mitigated enough by using timer, aquastat and TONS of insulation and shortest loop possible to keep heat loss to aminimum?
Right now I would choose loop system because the other seems unsanitary.
Got 5- 6 other questions but I'd like to see input on above first.
Thanks - anyone?

A damand system is one in which water is heated as its used. Where do you get the idea of cross connection?
Loop system does cost more to use but depending on where the hot water heater is located may be required by code. It may save some money on water use, but not on heating it. As you know you waste a lot of H20 wating for the heated water to get to the sink.

Hello,
A hot water recirculating system can give you instant hot water, but you must mind some important safety tips! Follow this guide for proper installation of your recirculating hot water system.
When water is heated, it simply gets lighter. It wants to float to the top of cooler water. Cool water wants to fall. If you have a loop that projects upwards, the cool water wants to fall down the loop while the hot water goes up. Gravity fuels the motion.
It works in this fashion in your house. You already have half of the loop in place. This is your hot water piping distribution system which begins at your hot water heater and ends at the farthest fixture which requires hot water. If you were to install copper piping leading back from the farthest point and from other high points in the existing system, you would have a loop. This return loop connects into the bottom of the hot water heater where the current drain valve is located. It is that simple.
The flow of water through the loop is very slow. However, that doesn't matter. The only thing that is important is that hot water is near each fixture. Without a loop there is no movement, so any movement is better than none!

Hey friends,
Hot water recirculation systems are commercially available nationwide through the manufacturer, distributor, plumbing wholesale supply warehouse or at selected retail home stores. Initial cost may prevent some from using recirculating hot water systems. Energy savings will vary depending on the design of the plumbing system, method of control and operation, and homeowner use.