Expansion tanks can relieve pressure from the water heater. You will still need to keep an eye on the pressure that occurs within the tank while the heating unit is turned on; the expansion tank can be used for the water to flow to while the heater is working. You should look around when fitting your RV with such a tank as there are sometimes less expensive versions available at home improvement stores. Sometimes these tanks hold a greater volume.
Expansion tanks can sometimes handle higher pressures than the normal water tank. This difference in pressure can allow the tank to fill more quickly. This lets the water pressure during output stay consistent. This can be particularly nice during a shower or if trying to wash dishes. In addition, it can make the water pressure higher, also nice for rinsing soap when cleaning.
The placement of the expansion tank should be considered. Depending on your RV layout, you can choose a location that will not disturb anyone who is sleeping within the vehicle. Often the main water tank is located in a central location. This can wake people sleeping on the living-room beds when someone flushes the toilet in the middle of the night. If you can place your new tank in the far front or rear of the unit, you might be able to eliminate this problem.
