We recently bought a remote freezer thermometer with two senders, and put one in a freezer and the other in a pump house about 20 yards from the main unit.

You can set either channel to chirp an alarm when the temperature rises or falls to a certain point--both could be freezer monitors, for instance, but we let one monitor the pump house and one a freezer. The freezer monitor--with the green background in the pic--is set to alarm if it rises to 10 degrees or so. The pump house monitor is set to alarm if it falls below 36 degrees or so.

The display stays lit if we leave the main unit plugged in, so it's nice to walk by it and see that the pump house is still plenty warm; it's "A Good Feeling to Know" (...reminiscent of a great old Poco song:  https://www.youtube.com/watch?v=sSsphZjV-G4&list=RDsSsphZjV-G4&start_radio=1 )  If running on batteries the display goes dim until you touch the screen.

We've had problems with that pump house freezing at various times over the years (heater died, electrical supply problem, etc.), so having a temp. monitor is comforting. Range on this thing is supposed to be ~300 feet, and I think it would do that with no walls, etc. in the way. Through a couple walls and a bit of snow 100' is more realistic.

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