Before starting a water heater installation project, whether on your own or by hiring a technician, it's a solid idea to prepare a checklist. Pay attention to these four items as you get ready.
Check the Codes
Even if you've previously dealt with an installation before, it's wise to get up to speed on what the current local, state, and federal codes for water heaters are. Many states have rules regarding local conditions, permit requirements, and licensing. Your municipality, township, or country should have a compliance officer who you can contact for more details about what applies to where you live.
Explore Your Options
It can be tempting, especially if you're replacing an existing system, to just get the closest one-to-one replacement you can find. There are huge opportunities to improve efficiency with a modern setup, though. For example, a tankless system can reduce the amount of water that is idled and has to be reheated. Even if you use a tank-based configuration, there's a good chance you can get something more efficient.
Look at the FHR and EF ratings on the yellow energy label for the tank. Respectively, these will tell you how much heated water is delivered in the first hour of operation and how efficient the system is. In both cases, higher is better.
Many people elect to relocate their heaters when performing an installation. If you want to do that, it's best to look at how the lines will be plumbed and make sure they're where you'll need them.
It's also wise to have the lines professionally inspected. They're going to be out of commission anyhow, and this is a good time to replace any that are old or compromised. Newer, flexible lines can be installed in tricky spots, potentially reducing the use of elbows and T's, too.
Don't assume a professional water heater installer will do all of the plumbing work. Ask in advance, and be prepared to pay extra if they do handle such jobs. If they don't, you should hire a plumber and have them come in at least a week in advance.
Turn Everything Off
The lines going into the heater, usually some combination of water and gas or electric, need to be turned off. You're going to have to do this for removing the old one and draining the water lines, anyhow. If you're not confident messing with those lines, it's best to have a professional deal with them. After that's squared away, you're ready to start the install.
For more information, speak with a water heater installer.