Start with what you have
Many newer homes came with either a high-efficiency tank or a tankless unit. When one reaches the end of its life, the easiest replacement is usually the same type in the same spot, because the gas line, venting, water connections and electrical are already sized for it.
Switching types is possible, but it is a bigger project. A tankless heater generally needs a larger gas supply than a tank, its own venting and an outlet for its controls. Going the other way means finding floor space and a vent route for a tank, plus seismic strapping.
How the two compare
Tank water heater
- Stores heated water, so many fixtures can draw at once up to its capacity
- Can run out of hot water during heavy use
- Sediment settles in the tank; periodic draining helps
- Must be strapped for earthquakes in California
- Takes floor space in a garage or closet
Tankless water heater
- Heats on demand, so it does not run out while within its flow rating
- Flow rating limits how many fixtures run hot at once
- Scale in hard water calls for regular descaling
- Usually needs a larger gas line and dedicated venting
- Mounts on a wall and frees floor space
What a switch can involve
| Item | Tank to tankless | Tankless to tank |
|---|---|---|
| Gas line | Often upsized from the meter | Existing line usually adequate |
| Venting | New vent suited to the unit | Vent route for a tank appliance |
| Electrical | Outlet for controls | Often none for a standard gas tank |
| Space | Wall mount; floor freed | Floor space and strapping points |
| Water connections | Service valves recommended | Expansion tank may be required |
What drives the cost
- Same type or switch
- A like-for-like swap uses existing gas, vent and water connections.
- Gas line work
- Upsizing gas piping can be a large part of a conversion.
- Venting
- Vent route length and wall or roof penetrations add work.
- Code items
- Strapping, expansion control, drain pans and relief lines may need updating.
- Permits
- Ask whether the permit is included and who schedules the inspection.
Which way to lean
- Ifyour current heater works for the household and only needs replacinga like-for-like replacement is usually the simplest path.
- Ifyou often run out of hot water with a tankask about a larger tank or a tankless unit, and have the gas supply checked.
- Ifseveral showers run at once in the morningcheck the tankless flow rating against that demand before switching.
- Ifyou do not want regular descalinga tank or added water treatment may be easier in Fullerton's hard water.
Questions to ask for a quote
- Is my gas line sized for the heater you are recommending?
- What venting will it need, and where will it exit?
- Will the install include seismic strapping, an expansion tank or a drain pan where required?
- Who pulls the permit, and is the inspection included?
- What maintenance will this heater need in hard water?
Common questions
Is tankless always more efficient?
Tankless units avoid keeping a tank of water hot, but real savings depend on household use. Ask a plumber to compare the specific models being considered.
Can I move the water heater to a new spot?
Often, but relocation adds gas, water and venting work and usually a permit. Ask for the move to be itemized separately.
Do I need a permit for a like-for-like swap?
Many cities require one even for a direct replacement. Check with the City of Fullerton.
General information for Amerige Heights, not a quote or professional advice. In an emergency, call 911.