Expansion Tank Sizing Calculator

Why does the expansion tank depend on temperature?

Water expands as it heats, and that expansion volume is what the tank must absorb. The tool uses the density of water at your cold-fill temperature versus your hot operating temperature, so a larger temperature swing produces a larger acceptance volume and a bigger required tank. This is why baseboard systems at 180 F need more tank than radiant systems at 140 F.

Related questions

• How do I size an expansion tank for a closed hydronic heating system?
• Does the expansion tank replace the relief valve?