Water changes with water that closely matches what is in the tank cannot hurt. As long as you use dechlor. So of you are using your tap water in the tank, just make sure the changing water is withing about 6 degrees +/- to what the tank temp is. A 50% water change means even 6 degrees one way or the other can only change the tank water temp by 3 degrees.
Make sure your heater will be submerged when you take out 1/2 the water. I usually place heaters horizontally near the bottom of the tank on the back glass. This helps to hide it. Plus heat rises, so when the heater is on it will move heated water from the bottom towards the top of the tank. It also means you do not need to remember to unplug it during water changes and then to plug it back in.
If you have to place it vertically, it is only the nottom half that does the heating so if you can insure that half always is well submerged during a water change that will work. But in such cases it is best to get some new water back in fairly soon so you know the heating element is safely under the surface. In cases like this I am usually staring the refill almost as soon as the emptying is done. Media has been rinsed etc, before the last of the water comes out.
Make sure your heater will be submerged when you take out 1/2 the water. I usually place heaters horizontally near the bottom of the tank on the back glass. This helps to hide it. Plus heat rises, so when the heater is on it will move heated water from the bottom towards the top of the tank. It also means you do not need to remember to unplug it during water changes and then to plug it back in.
If you have to place it vertically, it is only the nottom half that does the heating so if you can insure that half always is well submerged during a water change that will work. But in such cases it is best to get some new water back in fairly soon so you know the heating element is safely under the surface. In cases like this I am usually staring the refill almost as soon as the emptying is done. Media has been rinsed etc, before the last of the water comes out.