There’s nothing worse, especially in cold weather, than a shower that’s only lukewarm. If your water heater is disappointing you, it’s probably time to look for a new one (manufacturers recommend a life of between 8 and 12 years for most models). Since the water heater is an appliance we rarely see, it’s common to be intimidated by it, but don’t let that stop you!Choose a New ModelBefore you go shopping, gather some information from your old unit. There should be a nameplate on the appliance with information such as capacity, wattage and voltage, pressure, insulation R-value, and obviously the brand and model. Additionally, take careful measurements of the space your heater is stored in: height, width, and depth.There are many different choices that you will face when choosing a new water heater. You may want to learn more about the different fuel sources available to you, as heaters are available in electric, natural gas, propane, oil, solar, and heat pump varieties. Tankless heaters are also an option you may be interested in. Each of these options have their own pros and cons, so we recommend learning as much as you can before committing to a new type of water heater. If you do decide to switch fuel types, you may do best to seek a professional for your installation. Laying or removing gas lines, for example, is not a job for amateurs.Whether you stick with the type of heater you had before or choose a new one, your next decision will be about size. There are two important points in sizing: the actual amount of water it holds and the recovery rate, which is the amount of water it will be able to heat in one hour. The recovery rate is also known as First Hour Rating (FHR) on the Energy Guide sticker. Generally, if you live in a two-person household, you will be looking at a 30 to 40 gallon heater. Three to four people require a 40 to 50 gallon tank, and five or more should go with a 50 to 80 gallon model. (Be sure to think about potential growth in your family over the next several years, as well!) If you are considering a larger model, make sure that it will fit in the space you have for it!Your final selection, after choosing type and size, will probably come down to brand and price, but don’t ignore the Energy Star sticker. Choosing a more efficient model, even at a slightly higher initial cost, will pay dividends for you in savings on your energy bill throughout the life of the appliance.Remove the Old Water HeaterFirst step first: if you’re working with an electric water heater, turn off the breaker, and lock the box so it can’t be turned on again while you’re working. Disconnect the wiring from the old unit, and mark them or make notes so that you can reconnect them easily. Likewise, with a gas unit, turn off the gas and disconnect the inlet valve.Turn off the water supply to the heater, and turn on all the hot water faucets in the house. Connect a garden hose to the drain valve to remove all the water from the tank. Disconnect the cold water inlet pipe, and remove the unit. (They are heavy and bulky even when empty so you may want some help.)Install the New UnitInstallation is basically the reverse of removal! Position the new unit in the space. Reconnect the water inlet and hot water outlet pipes (soldering if necessary).All your hot water faucets should still be open – leave them that way until water begins to flow from all of them, to clear all air from the lines. Let them flow for one minute.Reconnect the fuel source. Double check to make sure that it is safely installed before proceeding to turn on the fuel. After about an hour, run your faucets again to make sure that the water is heating properly.Installation of a water heater can be an intimidating task, and with some reason: it does involve plumbing skills as well as requiring you to work directly with electricity or gas. If you’ve got the skills, though, you should be able to replace yours in a day, and be back to your life in no time.