Tankless vs Tank Water Heater
Which is right for your home? An honest breakdown from Terry Foster Jr., MD Master Plumber #98433 — including when tankless is not worth the extra cost.
Terry's Verdict
"Tankless makes sense for households of 3+ people with natural gas who run out of hot water. For a single person or couple with a working gas line, a quality tank replacement is often the better value."
Side-by-Side Comparison
| Factor | Tank Water Heater | Tankless Water Heater |
|---|---|---|
| Upfront cost | Lower upfront cost | Higher upfront cost |
| Lifespan | 10–12 years | 20+ years |
| Hot water supply | Limited by tank size | Unlimited (on demand) |
| Energy efficiency | Lower (standby heat loss) | Higher (no standby loss) |
| Space required | Large (40–80 gallon tank) | Small (wall-mounted) |
| Gas line requirement | Standard 1/2 inch | 3/4 inch minimum |
| Installation complexity | Simple | Complex (gas line upgrade often needed) |
| Best for | 1–2 person households, budget-conscious | 3+ person households, long-term investment |
Tank Water Heaters — The Full Picture
A tank water heater stores 40–80 gallons of hot water, keeping it ready at all times. The main disadvantage is standby heat loss — the heater must continuously reheat the stored water, even when no one is using it. Quality brands (Bradford White, Rheem) last 10–12 years with proper maintenance (anode rod replacement at year 6).
Installation is straightforward — same gas line, same venting, same footprint as the old unit. For a single person or couple who does not run out of hot water, a tank replacement is excellent value.
Tankless Water Heaters — The Full Picture
A tankless (on-demand) water heater heats water only when needed — no standby heat loss. They last 20+ years, take up far less space, and provide unlimited hot water. The catch: they require a 3/4-inch gas line (most homes have 1/2-inch), a dedicated venting system (concentric PVC or stainless), and a condensate drain for condensing models.
The gas line upgrade can add significantly to the installation cost. For a household of 3+ people who regularly run out of hot water, the investment pays off over time.
Decision Guide
Choose Tank If…
- 1–2 person household
- Budget is primary concern
- Existing tank is under 8 years old and repairable
- No space constraints
Choose Tankless If…
- 3+ person household
- Running out of hot water regularly
- Natural gas available
- Doing a full renovation
- Want 20+ year lifespan
Frequently Asked Questions
How much does a tankless water heater cost to install in Maryland?
A tankless water heater installation in Southern Maryland varies depending on whether a gas line upgrade is needed, the venting configuration, and the unit size. We provide upfront pricing before any work begins.
Do tankless water heaters work with well water?
Yes, but well water with high iron, hardness, or sediment can clog the heat exchanger in a tankless unit. We recommend a sediment pre-filter and, for hard water, a water softener upstream of the tankless heater. This is especially important in Southern Maryland where well water quality varies significantly.
What brands of water heaters do you install?
We install Bradford White and Rheem for tank water heaters — both are manufactured to higher standards than big-box store brands and carry better warranties. For tankless, we install Rinnai and Navien, which are the most reliable brands for residential natural gas applications.
Can I convert from a tank to tankless water heater?
Yes, but it requires a gas line upgrade (from 1/2 inch to 3/4 inch minimum), new venting, and possibly a condensate drain. We assess the existing infrastructure before recommending the conversion and provide a complete cost estimate including all required upgrades.
How long does a tankless water heater last?
A properly maintained tankless water heater lasts 20+ years — roughly twice the lifespan of a tank heater. Annual descaling (especially important with hard well water) and filter cleaning are the main maintenance requirements.
Not Sure Which Is Right for You?
Terry will assess your home's gas line, household size, and budget — and give you an honest recommendation with upfront pricing.