If you're handy with tools and have some basic plumbing knowledge, then installing an expansion tank yourself is certainly possible. However, there are a few things to keep in mind before undertaking this project.
First, be sure to purchase the correct size expansion tank for your home. These tanks are typically classified by the amount of water they can hold - so make sure you know how much water your home's plumbing system can hold before selecting a tank.
Next, you'll need to install the tank in a location where it can properly do its job. Expansion tanks must be installed upstream of the cold water shut-off valve and should never be installed in an attic or crawlspace (since these locations can get very hot or very cold). The ideal location for an expansion tank is on a wall near your home's main water line.
Once you've selected and prepared a location for your expansion tank, installation is relatively straightforward. First, shut off the main water supply to your home. Next, connect one end of a lengths of pipe to the cold water shut-off valve and run it up to the expansion tank location. Secure the piping to the wall using brackets or clamps (be sure not to overtighten!). Finally, connect the expansion tank to the piping and open up the main water supply again.
That's it! With just a little bit of planning and elbow grease, you can easily install an expansion tank in your home without having to call in a professional plumber.