This product must exist somewhere

Mike T., Swampeast MO

Some alarm system brains have extra contacts that can be operated with certain conditions. They will either provide a small amount of power (generally to operate a relay coil) or be "dry" whereby they either pass or don't pass current. With either pay particular attention to the ratings of the current provided or the switching ability of the contacts.

Shutting down the heating/cooling system if a window or door is open sounds like a rather bold action. You would certainly want a significant delay before actually shutting things down. "Delay on make" and "Delay on break" adjustable electronic relays are both available.

While I think I understand the logic behind such a system I don't believe you would want the system to shut down if it is near or below freezing temperature outside. You wouldn't want the structure to freeze because of a faulty window/door contact! A mechanical outdoor temperature sensor could likely be used to prevent this from occurring.

If you do this I think you should include some form of prominent visual and/or audio indication that the heat/cool system is shut down because of an open door/window situation.

Wilson

This product must exist

I'm looking for some kind of switch that will shut off a boiler or AC when home security alarm system indicates that a window or door is open.

[Deleted User]

X-10

X-10 has lots of gizmmos like that. X-10.com

Aidan (UK)

Done with

This is done with DDC/BMS systems, using magnetic reed switches on windows to disable AC in that particular room. It's not a common requirement, so the system has to be programmed for this particular application. A BMS/DDC solution would be beyond DIY.

It wouldn't be difficult to contrive a DIY system with a reed switch operating a relay, with separate contacts for alarm system inputs or to disable the heating &/or cooling via electric zone valves.

Bob_9

I've got a Honeywell telephone access module with a PC8900 thermostat on my house. The great thing about it is that if the indoor temp goes above or below preset temps the module will dial out to my office, cell phone and my dad to alert of a fault.
If you were to have a window or door open and the equipment shut off what prevents a freeze-up? It seems you'd want a device to alert someone of a problem.
Bob