an integral water circulation apparatus supplies instant hot water at hot water faucets remotely located from the building water heater through a convective circulation flow of hot water from the water heater it is therefore simpler in design , less expensive to install , and more reliable than the more complex prior art systems . it has the further advantages of not mixing heated water with cold water being supplied to cold water faucets throughout the building and of preventing cold water from flowing up the return line to the hot water faucet