How to Buy a Replacement Water Heater
Water Heater Installation
Water Heater Replacement Basics
Before you go shopping take a careful look at your existing water heater and make careful notes about what you see. You would not believe how hard it is to remember exactly what pipe sizes and fittings you are dealing with as you stand in the store looking at all the choices.
In our case we know the water heater probably failed so quickly because of our extremely hard water and failure to drain the sediment regularly. That being the case we though we should check into the idea of adding a water softener to our system. That would more than double the cost, but would probably be worth it long term. Unfortunately, when I looked at the pipes closely I realized the water supply coming in to the water heater is after the cold water T's off to the rest of the house. In other words, there is no way to put a water softener into the room with the water heater and soften the cold water side. There has been a lot of really strange work done to this house (prior to our arrival) and I have no idea where the water lines divide. A water softener will have to wait for another time.
The picture shows my old water heater top after I had taken off the supply lines. You can see they are the metal clad flex lines. They are not corroded or coated with lime and were not stiff. The blue plastic at the base of the right nipple tells you this is where the cold water supply enters. The red on the left indicates the hot water outflow side. The black pipe on the left is the propane supply line. (Anytime you see black pipe you are dealing with a gas line.) The brass fitting on the lower right is the pressure relief valve. The shutoffs were part of the attachment of some other unit from before I owned the house.
Both flex connectors have a female fitting that goes onto the male nipple.
In your house are the supply lines from the wall into the water heater still flexible or not corroded? Are they old enough their gaskets and/or seals will be brittle and crack when reconnected? Exactly what kind of connector is on each end of each supply line?
If it's a gas water heater, is the gas supply line in good condition? What size and type (male-Female) connectors are on each end of the gas supply line. Are there adapters on either end that change the size of the required fittings?
This is the gas supply for my old water heater. (You can click on the picture to see a MUCH larger image.) At the top left you see the red shutoff valve. Valves always have the handle going the same way as the interior parts. Since the handle is at right angles to the gas line you know the gas has been turned off at the valve. If you look closely you will see there is a reduction fitting which sizes down the black pipe so it fits onto the flexible gas line. The same is true on the other end of the gas flex line; there is an adapter to make the line fit into the gas valve.
There is no reason for using the adaptors; it would make more sense to use a line with the right size fittings. That would be two fewer places for a leak. It probably means whoever installed this didn't have the right size flex line, but did have a couple of adaptors. Hey, it saved a trip to the store.
Gas comes in two flavors. Natural gas and propane. Propane is more dense than natural gas, so the gas controller valve has a different size opening. You want to be sure you get the right one. In my house I needed one set up for propane.
If you live in a mobile or manufactured home you must buy a water heater specifically designed for that. It will be labeled "Mobile Home use" on the carton. Mobile homes have smaller water heater compartments so the sides of the water heater are very close to the walls. Manufactured home water heaters are called zero clearance water heaters and are designed to run cooler to eliminate the risk of fire. If you try to save a few bucks and install a standard house water heater, the first inspector who sees it will red tag it immediately!
Both Home Depot and Lowe's (the two choices available where I live) have displays that show Good, Better, Best water heater lines. The more expensive, the longer the warranty. Unfortunately, for the propane kind I needed, they had exactly one choice. I'm sure I could have special ordered a different one, but that didn't seem like a great idea given the serious leaks I already had.
If you have an electric water heater draw a sketch of the outlet it plugs into. You will need to make sure the plug on your replacement water heater will fit.
Replacement time is an opportunity to change the size of your water heater. They come in 30, 40, and 50 gallon sizes. If you have been frequently running out of hot water, consider buying a larger size. On the other hand, heating a larger unit will increase your costs, so don't change unless you need to. You will also need to make sure a larger unit will actually fit into your space. If you are buying a larger electric unit you will want to make sure your existing wiring can handle the current load. I don't believe capacity is ever an issue with gas supply lines.
Once you have picked out your new water heater you have to get it home. Water heaters don't like to lie on their sides! The carton will have specific warnings not to transport them any way except upright. That's a problem if you or a friend don't have a truck. I suspect that if you drive carefully, avoid speed bumps, and pad the carton well, you can probably get a water heater home in your trunk. I don't think you will have much luck with a return if there is a big crease in the carton though.
Removing your old water heater