The best replacement for expansion tank is pressure tank.

The best alternatives to expansion tank are rated as following:
★★★★★  pressure tank
★★★★  overflow tank
★★★★  compression tank
★  header tank
★  pressure relief valve
★  buffer tank
  pressure reducing valve

Your alternative for expansion tank is not listed? Suggest!
Speaking about expansion tank, one probably shouldn't forget about water heater.

Other search terms related to expansion tank and their ratings are:
★★★★★ water heater
★ hot water heater
backflow preventer
You have in mind a companion for expansion tank and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of expansion tank in all years. Click on graph for more.
expansion tank
pressure tank
overflow tank