A little background:
I have a client who owns a small chain of self-serve car washes in the mid-west. During the winter months, he has to run "floor heat" in each car wash bay to keep ice from forming on the ground. This floor heat consists of hot water flowing through pipes beneath the concrete. He must turn each system, essentially pumps controlled by electronic switches, on and off manually at each of his locations. With the rising natural gas prices, running the floor heat is costing him a fortune. So, to cut down costs, he turns the systems off on milder days, when the temp get above 35 degrees F, but the night-time temp will still drop below freezing so he needs to make another trip out to all his locations to turn the systems back on.
He wants to be able to turn these systems off and on over the web so he doesn't have to spend so much time driving to and from each location.
From what I know I should be able to set up the computers he has at each location with a PC board and software that can control these switches. What I need is a starting point of what to look for. I haven't found much online but I think it's because I'm not sure the proper terminolgy I need for something like this. Once I get the system set up, I can handle setting up access to his systems over the web.
So, I need to know what hardware/software/parts I need to set up a WindowsXP computer to turn small industrial pumps on and off.
Can someone point me in the right direction here?