Gas Tank Water Heater Recommendations

[Christian Latimer]

Any recommendations for which to get. There are a ton of options when I looked at Home Depot. 

Looking to stay with gas tank type. 

3 bed/3 full bath 1600 sq ft house.

I need to replace the current gas tank water heater that is in a closet. 

[Matt R.]

Disclaimer: I am not a professional plumber.  I have installed and reworked the installation of water heaters before.

I don't know, but I am told that the typical 6, 9, and 12 year models at the hardware store either 1) don't differ mechanically at all- they're just building an extended warranty into the price or 2) differ only in the anode rod, which keeps the tank from corroding - the longer-warranty models have a thicker or longer anode rod.

If you never ran out of hot water with the one that's there now, then get one the same gallon size.  If you did run out of hot water, consider going up one size, if it will fit in the closet.

In each size, the most common configuration is probably the tall and skinny one.  You can also get a "lowboy" version of most sizes that is short and fat.  These may not be on the shelf at HD, Lowe's, etc but they can order one.

Even if you're replacing with one the same gallon size, measure the closet with your tape measure, and compare that to the dimensions in the new heater's manual, before you buy - they aren't all exactly the same.  Also check to make sure you have enough room around the water heater - a lot of them specify 0" clearance around the sides, but require clearance in front (for the gas valve) and on top (for the flue).

Some of the higher-efficiency models have a vent blower on the exhaust (similar to high-efficiency furnaces).  The blower usually needs 120 V AC.  I think it's only a couple of amps, so it doesn't need its own circuit or anything, but you need to have an outlet or junction box reasonably near the water heater.

Does the closet currently have a louvered door, or vent louvers in the walls, or maybe a pipe coming down from the attic or in from outside (not the flue pipe - a separate one, just for air) to provide air for the water heater?  If it doesn't, you need to install one.  The water heater manual will tell you how many square inches of vent area you need.

Is the closet in a garage or basement?  If so, is the water heater currently sitting on the floor?  In some locations, you are now required to have the new water heater raised up off the floor - they are worried about flammable gases along the floor being set on fire by the water heater.  The hardware store sells a steel "chair" to set the water heater on, that will meet this requirement.

Always get a new temperature and pressure relief valve; don't re-use the one from the old heater.  It's OK to re-use the drain pipe for that valve, if the existing one is in good shape.

If the existing heater has flexible water hoses on the input and output, replace them as well.  The hoses come in different lengths; get the shortest one you can that can make gradual bends to attach at both ends.  There's a chance you might have to put a 90 degree elbow on one of the pipes to get the flexible hose to route how you want.

If the existing heater has a flexible gas connector, consider replacing that.  MAKE ABSOLUTELY SURE YOU UNDERSTAND WHICH PARTS OF THE FLEXIBLE GAS PIPE GET PIPE DOPE OR THREAD TAPE, AND WHICH PARTS DO NOT.  The house you don't blow up may be your own.

If the water heater is inside the "finished" area of the house, and if you have a way to run a pipe to a floor drain or other open drain, consider installing a drain pan under the new water heater.  It will do absolutely nothing unless the water heater springs a leak, but then it will probably limit the amount of flooding in the house.