Picture this: You are out of town, left in a hurry and forgot to change your thermostats before you left. The vision of dollars going up in smoke fills your mind when you think of air-conditioning an empty house.

Now imagine that you can lift the lid on your notebook computer, dial in to the Internet from your hotel room and access your home control system to change the thermostats. Oh, and while you are there, you check the thermostats of your kids’ rooms and adjust them, too. You also turn off a couple of lights and check to see that the pool pump turned off on schedule.

Sound far-fetched? Well, this is actually a true story of my travels last week. And while I’ve had the power of a home automation system for the last two years, its value hit me when I realized that I could control my thermostats and check on the house activity from 1,600 miles away.

For me, the path to home automation started two years ago when I found low-cost home automation software called HomeSeer, located at www.homeseer.com . This software can be set up on one computer but uses separately purchased hardware to connect to power lines, infrared devices, radio transmitters and almost anything else in your house.

This software is surprisingly simple to set up, but has incredible power to control just about everything in a home. Wired or wireless, you can connect to it all over power lines.

It is also some of the best written Windows software that I’ve ever seen. In fact, I’ve jokingly told my friends that Bill Gates ought to hire the program’s author, Richard Helmke, to teach other’s how to program for Windows. Helmke has built infinitely extensible software that doesn’t go off on tangents. It is well behaved and as such takes advantage of speech agents, scripting, and runs on just about any version of Windows without a hitch.

With just a Web browser you can control lights, appliances, a security system — almost anything with a power switch. In my home, the system controls the pool pumps and cleaner, opens and closes drapes, and even tells me when someone is coming up the driveway or if I left the garage door up.

In fact, my house talks. The computer running HomeSeer is hooked up to a whole-house audio system and the system tells me when an exterior door is opened or when someone is walking in the back yard at night. During the day, it checks the weather on the Web and reads the forecast to me. It can also read me the technical and business news whenever I want.

My system can also recognize voice commands, perform tasks according to a schedule or respond to something, like the trigger of a motion detector. As it performs activities, it logs everything to a file so I can see what happened and when. It can even be set up to receive or send e-mail.

The cost to get started is low. The software sells on the Web for $79.95. You need an X10 starter kit from online stores such as X10 Home Solutions, at www.x10.com/products/product_list3.htm , for as little as $49.99. If you don’t like X10, no problem. The software supports a wide range of home automation devices. (See the list following this article.)

Once you get going, watch out. You can get a taste of automating with a few lights or an appliance. If you like the idea, you can join me in hooking up just about every device possible to the system.

I’ve got scripts for night lights, art lights and a host of other automated tasks. There are a few caveats, though, in larger homes. The signals sent to devices fade if traveling too far. But these can be overcome with a willing electrician and patience to debug the system. There’s plenty of support at sites such as www.smarthome.com and through e-zines such as this one who can help give people ideas.

Having a little automation not only saves money but also can provide peace of mind. When I checked my house last week, I found that my son returned home by 11:30 p.m., triggered the driveway sensor, opened and then closed the garage door. Another door to the house didn’t open until 7 the next morning.

HomeSeer supports:

* X10 ActiveHome CM11A X10 serial interface (two way interface)
* X10 CM17A RF serial interface (one way, send only X10 interface)
* All CM11A compatible interfaces such as the IBM Home Director HD11A, the Radio Shack plug’n power interface, and the X10 CM12U.
* Applied Digital Ocelot/CPU-XA (X10/Infrared/Input-output serial interface)
* MR26A RF Receiver
* ACT TI103 X10 interface (X10 only)
* SmartLinc HouseLinc home controller (X10 and infrared)
* NIRVIS Slink-e (infrared, Sony Control-S)
* JDS IRXpander (Infrared) .
* Supports SmarLinc SwitchLinc wall switches and PCS wall switches
* Supports the RCS TX15B bi-directional thermostat for HVAC control