I used mine all last year and it only froze when temps were below 10 degrees. But, last year I used a 25 watt bulb and hadn't put any insulation inside the tin. This year I bought the felt insulation you can nail around drafty windows and some tin tape (think of sticky tinfoil) and used them to insulate the inside of the tin. First, I wound the felt all around the sides and then cut strips of felt to cover the bottom. After the felt was in place I completely covered every inch of it with the tin tape to make everything fireproof.
I then tried out a 40 watt bulb but removed it because after less than 5 minutes the top of the tin was scorching hot. Back to a 25 watt bulb...you want the water above freezing but not warm as that will encourage bacterial growth. (I scrub the waterer with bleach once a month to help with this.)
Put the tin out in the coop with my large 3 gallon metal waterer sitting on it and it's doing great. Water isn't freezing and also isn't warm to the touch. I do turn it off during the day both to conserve energy and to reduce temp of the water. I'll leave it on all the time if outside temps stay below freezing.
To answer a previous question--you want the bulb mounted so that it sits in the middle of the tin, not touching the bottom, sides, or top. And, I bought the entire bulb-and-cord unit at my local hardware store in the section for rewiring lamps for about 5 bucks.
Note: if you're worried about fire, first be very careful how you mount the cord. Chickens will do crazy things, so don't make it possible they could jiggle the cord. Second, add duct tape around the outside of the tin where the socket emerges so any splashed water could not drip down inside the tin.
I've also seen totally different methods where people place lightbulbs inside hollow cement blocks or inside overturned terra cotta pots. You might feel safer with those options, but there's always the fact that you have water and electricity in close proximity that needs to be considered.
I then tried out a 40 watt bulb but removed it because after less than 5 minutes the top of the tin was scorching hot. Back to a 25 watt bulb...you want the water above freezing but not warm as that will encourage bacterial growth. (I scrub the waterer with bleach once a month to help with this.)
Put the tin out in the coop with my large 3 gallon metal waterer sitting on it and it's doing great. Water isn't freezing and also isn't warm to the touch. I do turn it off during the day both to conserve energy and to reduce temp of the water. I'll leave it on all the time if outside temps stay below freezing.
To answer a previous question--you want the bulb mounted so that it sits in the middle of the tin, not touching the bottom, sides, or top. And, I bought the entire bulb-and-cord unit at my local hardware store in the section for rewiring lamps for about 5 bucks.
Note: if you're worried about fire, first be very careful how you mount the cord. Chickens will do crazy things, so don't make it possible they could jiggle the cord. Second, add duct tape around the outside of the tin where the socket emerges so any splashed water could not drip down inside the tin.
I've also seen totally different methods where people place lightbulbs inside hollow cement blocks or inside overturned terra cotta pots. You might feel safer with those options, but there's always the fact that you have water and electricity in close proximity that needs to be considered.
