cold weather controlled outlet

Thread Starter


Joined Dec 12, 2011
Hi, I'm new to your forum and need some help. I'm fairly handy and I'm looking to build a simple thermal switch that I can control a light bulb with to keep my swimming pool pump from freezing. the pump is covered in a plywood box, so I'm thinking I can plug in a utility light that is comes on when the temperature drops to freezing, then shuts off when it warms up. I have an exterior outlet I can plug into, but not sure how to build a switch, or if I can buy one somewhere.

Any help would is appreciated.


Joined Feb 19, 2009
Most pumps around here a 75-100W bulb is just left on all the time, rather than controlled to keep the enclosure at borderline freezing.

An extra kWH/day over a switched solution, so call it 12 cents/day. I think the theory is it's easier to keep something at a temperature than it is to warm it up to that temp.


Joined Sep 9, 2010
That's a pretty cool little device.

It'll be tough for any DIY solution to beat an off-the-shelf thermostat for this application. You might be able to repurpose the thermostat from an old electric blanket. Or search this forum for egg incubator solutions.