What size should heating pipes be?

The radiator circuits in most modern wet central heating systems are made from standard 15mm copper pipe, while the pipes that link the boiler, pump and points where the circuits split off will be 22mm or 28mm in diameter.

How do you size a hot water pipe?

Pipe sizing is determined by the flow rate of each fixture in gallons per minute (gpm) and the maximum acceptable velocity (in feet per second) of the pipe used to serve it. Note that velocity increases as pipe diameter decreases.

What size pipe should run to water heater?





Most of the water heater inlet size comes with ¾” or ½” diameter. ½” is a common measurement for old households. These days most water heater supply lines require ¾” diameter inlet size. For a tankless water heater, the size mostly varies from ¾ inch to 1 inch.