Watch this video from This Old House to learn how to install a towel warmer.
1. Drain hot-water heating system; turn off water supply to the old radiator.
2. Use reciprocating saw to cut hot-water supply and return lines from old radiator; remove radiator.
3. Cut open floor for relocating new hot-water supply and return lines.
4. Hold towel warmer against wall and mark its location.
5. Cut and dry-assemble copper pipe and fittings to extend the hot-water supply and return lines to new locations.
6. Solder together the copper pipe and fittings.
7. Sweat a threaded copper adapter onto the end of each hot-water line.
8. Replace the plywood subfloor.
9. Thread chrome nipple with shut-off valve into each copper adapter; tighten with adjustable wrench.
10. Mark the positions of the hanger bases on the wall.
11. Use toggle bolts—or wood screws if you hit studs—to attach the bases to the wall.
12. Attach the towel warmer to the hanger bases.
13. Use adjustable wrench and pliers to connect the chrome shut-off valves to bottom of towel warmer.
14. Turn on water and check for leaks.