Water heater installation

What a complete installation includes

This is the part worth reading before you compare two prices, because the cheaper quote is usually cheaper for a reason you can name.

Removal and disposal of the old unit. Straightforward on a garage install, considerably less so from an attic or a second-floor closet.

A drain pan piped to a safe termination. Required anywhere a leak would cause damage, which means every attic and every interior closet. The pan is useless without a drain line running to the exterior, and a pan with no outlet is one of the most common defects found on existing installs.

A T&P discharge pipe of the correct diameter, running downhill, with no valve, no threaded end and terminating where a discharge is visible. Not into the pan on many jurisdictions' reading, and never capped.

An expansion tank where the house has a pressure regulator or a check valve at the meter, which is most of them. It has to be sized and charged to the house's static pressure, not simply screwed on.

New flexible or hard connectors, new shut-off valve, new nipples. Reusing twenty-year-old dielectric nipples on a new tank is a false economy that shows up as a weep two years later.

On gas: a sediment trap, an approved flex or hard pipe connection, and a vent connection that actually draws. On electric: correctly sized conductors landed properly, and a disconnect where required.

Permit and inspection where the jurisdiction requires one, which in most Texas cities it does. A permitted install is also the document that protects you at resale.

Sizing without guessing

The default answer is to fit what was there before, and it is right more often than not, but it is worth ten seconds of thought, because the two failure modes are showers that go cold and a tank heating water nobody uses.

First-hour rating, not gallons. The number that matters is how much hot water the unit can deliver in the first hour from a full, heated start. A 40-gallon gas heater with a strong burner frequently out-delivers a 50-gallon electric, because recovery rate is part of the answer.

Count the simultaneous demands. Two showers at once is the usual peak in a family house. A large soaking tub is its own category and is the single most common reason a correctly sized heater feels too small.

Recovery matters more with electric. A standard electric tank reheats slowly. If the household runs back-to-back showers, either size up or accept the wait.

Physical constraints are real. Attic hatch width, closet depth, garage clearance to the car, and vent height all limit what can physically go in. Taller-and-slimmer or shorter-and-wider variants exist in the same capacity, and a good installer measures before ordering.

Do not size up reflexively. A bigger tank in the same space costs more to buy, more to run, and can create clearance problems that turn a two-hour job into a half-day.

The code items that change a quote

Replacement triggers current code for the work being done. These are the items that most often turn a straight swap into something more.

Pan and drain. Adding a drain line from an attic pan to the exterior is real work. It has to fall the whole way and terminate visibly. Frequently the largest single adder on an attic replacement.

Expansion tank. Inexpensive, quick, and required far more often than it is fitted. If your existing install has none and the meter has a regulator, expect one.

Combustion air. A gas heater in a confined space needs adequate air. Closets built tight, or louvred doors replaced with solid ones during a remodel, create a problem the new heater inherits.

Vent sizing and material. Common on older houses that once had two appliances on a shared flue and now have one. An oversized flue on a single appliance does not draw properly, and the fix is a liner or a resize.

Platform and clearance. Garage installs in many jurisdictions require the ignition source elevated or the unit to be a flammable-vapour-ignition-resistant model. Modern tanks generally are, but the platform question still comes up on older garages.

Seismic strapping is not a Texas concern; wind and attic access are. What matters here is that the unit is sitting level, on a sound platform, with room to service it and a route to get it out again.

What the day looks like

Water off, heater drained. Draining a scaled tank is the slowest part of many jobs, and a heater that has never been drained can take a while to give up its contents.

Old unit disconnected and removed. On gas, the gas is isolated and the vent broken down. Getting a full-size tank down a pull-down attic ladder is a two-person operation and the point at which ceilings occasionally get damaged. Ask how it will be brought out.

New unit set, connected, vented. Pan first, then the tank, then water, then gas or electric, then vent.

Fill, purge and light. The tank fills with the hot side open at a fixture to purge air. Firing an electric element in a partly filled tank destroys it instantly, which is why the sequence matters.

Leak check and commissioning. Every joint checked hot and cold, gas connections tested, temperature set, T&P verified, expansion tank charge matched to house pressure.

Typical time: two to three hours for a straightforward garage swap; four to six where an attic is involved or corrective work is needed. Hot water is back the same day in nearly every case.

Choosing what to put back

Same fuel, same type is the cheapest and quickest path, and for most households it is the right one. Gas stays gas, electric stays electric.

Switching electric to gas means a gas line to the location, a vent, and combustion air. Rarely worth it purely on running cost unless a gas line is already close.

Switching to tankless is a genuine upgrade with genuine prerequisites: gas capacity, new venting, condensate handling and, usually, a different location. It is a different job with a different price, and it deserves its own conversation rather than being decided at the moment your old tank fails.

Moving the heater out of the attic is worth asking about while everything is disconnected. If a garage or utility location is feasible, the reduction in downside risk is significant, and this is the only moment the move is cheap.

Warranty. Tank warranties run six to twelve years and largely track the anode rod supplied. The longer-warranty version of the same heater is usually the same tank with a better anode. That is not cynicism; it is a reasonable thing to buy, particularly in hard water.