Bird Bath Heater Guide: Wattage, Solar, Safety

Birds need drinking water every day of the year, and in a hard freeze the open water in a yard disappears long before the food does. A bird bath heater keeps one small patch of water liquid so birds can drink without burning energy hunting for it. Here is how to pick the right one, what wattage actually buys you, and where solar fits.

How many watts do you need?

Wattage is about how cold it gets and how much water you are keeping open, not about how warm the water becomes. A de-icer is not there to make a warm bath. It is there to stop ice forming.

• 40W to 60W: small dishes and mild winters. Fine where the temperature dips below freezing overnight and recovers during the day.
• 70W to 80W: the common middle. Suits a standard 16 to 20 inch basin through a normal northern winter.
• 150W and up: large basins, exposed sites, and places where it stays below freezing for days at a time.

Going bigger than you need mostly costs you electricity. Going smaller than you need means the surface skins over on the coldest nights, which is exactly when the birds need it. If you are between sizes, size up.

Solar bird bath heaters: what to expect

Solar is the most requested option and the one most likely to disappoint in deep winter, for a reason worth understanding before you buy.

A solar panel produces power only while sunlight is hitting it. Winter is when you need a de-icer most, and winter is also when the sun sits lowest, the days are shortest, and overcast stretches are longest. A solar unit with no battery stops the moment the light goes, which means it stops every night, and the coldest hours are at night.

Solar still has real uses. A solar bubbler or fountain keeps water moving in spring and fall, and moving water resists freezing a little longer than still water. If your goal is open water at 15 degrees at 3am, a plug-in de-icer on a thermostat is the tool that does that job. If your goal is a good looking moving water feature from March to November, solar is a fine choice.

Submersible de-icer or a heated bath?

There are two ways to buy into this.

• A de-icer you drop into the bath you already own. Cheapest route, and it keeps the bath you like. Most sit flat on the bottom or float. Check that the shape suits your basin, since a tall unit in a shallow dish will sit proud of the water.
• A heated bath with the element built in. Tidier, no visible unit in the water, usually more expensive. Worth it if you are buying a bath anyway.

If you already own a bath you like, the de-icer is the obvious pick. Look for a thermostat, so the element only draws power when the water is near freezing rather than running around the clock.

Deck mount, pedestal, or ground level

Height is about which birds you want and how close you want to watch them. A deck mounted bath puts the action at window height and keeps it within reach of an outdoor outlet, which matters more than people expect once there is a cord involved. A pedestal bath in the open gives birds a clear view of approaching cats. Ground level baths attract the widest range of species, including ones that rarely use a raised bath, but they also put birds at their most vulnerable, so keep them well away from dense cover a cat could hide in.

Whichever you choose, the outlet distance decides the layout. Measure before you buy.

Safety and setup

• Use a GFCI protected outdoor outlet. This is water and mains electricity in the same place. If your outdoor outlet is not GFCI protected, have that sorted before anything else.
• Never run a de-icer dry. Most units are designed to sit in water and can be damaged when the basin empties. Check the level, especially during a dry cold snap when evaporation is faster than you would guess.
• Keep the water shallow, around two inches. In hard cold you want birds drinking, not fully submerging and then flying off wet. Shallow water and a rough surface to stand on handles both.
• Keep connections off the ground. Loop the cord so meltwater runs away from the join rather than into it, and keep the connection clear of standing water and snow.
• Use an outdoor rated extension cord if you need one, not an indoor cord run out through a window.

Keeping it working through the season

Open water attracts more visitors than a feeder does, which means it gets dirty faster. Plan to rinse and scrub the basin regularly through the winter, more often than you would in summer, because the water is not being flushed by rain as often. Unplug before you clean it. If ice forms at the edges on a very cold night, that is normal. What matters is that the centre stays open.

One thing worth knowing: once you start, the birds come to rely on it. If you are going away for a stretch in January, that is worth planning around.

Bottom line

Match the wattage to your winter rather than to the biggest number on the shelf, put it on a GFCI outlet, keep the water shallow and clean, and treat solar as a three season water feature rather than a deep winter de-icer. Our 70W bird bath heater sits in the middle tier with a thermostat and automatic shutdown, and drops into a bath you already own. See it alongside the rest of the Backyard Birding range, including a squirrel proof feeder for the seed side of winter feeding.