Pond deicers or commonly referred to as pond heaters are either floating or sinking pond deicers that de-ice or keep an area from freezing in your pond. They are thermostatically set by the manufacturer to turn on at a given temperature just above freezing and keep heating an area until temperatures exceed that temperature when the unit will shut off.
There are floating pond deicers and sinking deicers. The floating deicers usually float in a small area to keep an area on the top of the pond from freezing over solid. This is to allow toxic gases that are within the pond an exit hole to escape while, at the same time, allowing that same hole an entrance for fresh oxygen to enter. This hole in the ice can be created from a floating deicer or even a properly placed and size of pond aerator - which you can operate year-round.
The sinking pond deicers are placed at the bottom of the pond to keep water temperatures around the deicer from freezing. This can provide a little warmth to a few fish that may huddle around it.
The big misnomer is that a pond deicer is a pond heater and that is not correct. Pond deicers like those below are for very small backyard ponds. They will NOT heat the entire body of water - like an actual heater would - but only deice it and keep a very small area from freezing solid. Pond heaters, on the other hand, are actual heaters that heat the entire body of water. They run into the hundreds or thousands of dollars and can be very expensive to operate. We do not currently offer those.