Replacing a shower head is the simplest renovation you can do to upgrade your bathroom.
There are a few reason why you might consider changer a shower head.
Your old shower head did not age well. Limescale is created by heating hard water. If you - or the previous owner/renter - did not clean it regularly, it accumulates over time and looks dirty.
You want to dramatically reduce your water consumption. Most recent shower head use a low-flow technology that reduce the amount of water running per minute.
Since your are working after the valve, you do not need to shut the entire water supply. You are not taking too much of a risk by attempting this operation either. Your are essentially just plugging a hose on a tap. As long as the valve is shut you can work freely; if you see leaking when the valve is opened just turn it back off while you fix it.
Most of the time you do not need tools at all.
If you do need some assistance (old shower head tied too strongly for instance) here are the tools you can use:
The same instruction applies wether your are dealing with a fixed mounted shower head or a hand-held showerhead.
1. Remove old shower head
Grip the shower head with your hand and turn counter-clockwise to remove it. It should come off easily.
If it was too tightened and you are unable to remove it by hand, wrap the towel around the piece. Now adjust your crescent wrench around it and unscrew. This should give you the extra strength necessary.
The towel improves traction while also avoiding scratches, in case you want to re-use the old piece.
Clean the dirt or any excess material on the pipe before moving to the next step.
2. Wrap with the teflon tape
The teflon tape seals the installation so it does not leak.
Cut a section a teflon tape and wrap it clockwise around the thread three times. When the tape is in place, press with your finger to smooth it in.
3. Install the replacement
Take your new kit and screw it onto the arm. Do not force too much, a careful hand-tightening is enough.
Even if you had to use a crescent wrench when removing the old one, stick to hand-tightening.
4. Check your installation
Open the valve and check for leaks. If you find any, start by tightening the head a bit more. If it persists, remove the shower head, improve the sealing with the teflon tape, place it back on and check again.
If there is no leak, congratulations you have succeeded!