I have ranch style house with hardwood floors...
1. If I open the basement registers, does it help with heating the main floor? (Concept of heat rises). Or is it better to close some/all of them to force more heat upstairs.
2. If I close all of them does that put my water pipes in jeporady? (I live in Michigan) 3. The bedrooms on either side of mine are not used most of the time and the other two walls are outside walls. If I close the registers in the two bedrooms adjacent to mine-does the fact they are colder rooms in winter months affect the ability to maintain a comfortable temperature in my room? Thank you so much.

I'll try to answer your questions as presented.

#1 If you are not using a room, you can close back the register-note I did not say CLOSE the register. Your HVAC system functions in a loop. Air is pushed out of the supply register and returned by the return grills. Interrupting any of them disrupts the flow and causes more or less air to circulate depending on the room layout. If you heat an unused basement, you are wasting money. However, not having some air circulation, particularly in a basement, allows humidity to build up causing mildew, so some air flow should continue. Hot air rises but it will be tempered by outflow through the walls and windows.

#2. Pipis-Possibly, depending on ambient temps. We don't know where the pipes are located or how cold it will get. As far as cold rooms and heated rooms. There is really no such thing as cold, it is lack of heat. Heat flows to cold, that's why insulation is put into outside walls and ceilings. If you do not heat rooms opposite yours, the same possibility of mildew and poor air flow will exist, and the heat from you walls will flow to the unheated walls as the heat tries to reach equilibrium. So you will feel cold as your body radiates heat to the colder walls, and interior walls are not usually insulated.

The best solution for energy cost control and comfort is to insulate well, use a high energy furnace, thermopane windows and turn the heat down a couple of degrees and wear heavier clothing. Use small space heaters when appropriate.

Hope this helps.