Where the efficiency comes from
A tank water heater keeps tens of gallons hot around the clock, whether or not anyone is using hot water. Some of that heat leaks through the tank walls, which is called standby loss. A tankless unit heats water only when a tap opens, so it has no stored water to keep warm.
That is the whole efficiency argument, and it is a real one. The saving is largest in a home that uses little hot water, because the tank spends most of its day idle. It is smaller in a home that runs hot water nearly all day, since the tank would be working then anyway.
Tank versus tankless: what changes day to day
Efficiency is only one line in the comparison.
Storage tank
- Lower purchase price and simpler installation in most homes.
- Stores a fixed volume, so a big family can run out during back-to-back showers.
- Loses heat all day to standby loss.
Tankless
- Endless hot water as long as the flow stays within the unit rating.
- Higher purchase and installation cost, often with larger gas or electrical needs.
- Needs periodic descaling to keep its heat exchanger working.
Want tankless priced for your house?
Call the 24/7 line to schedule a visit and get a clear price before work starts.
Flow limits: the catch with on-demand hot water
Every tankless unit has a maximum flow rate in gallons per minute at a given temperature rise. If two showers and a dishwasher run together and the total demand passes that rate, the water turns lukewarm. Sizing is therefore the most important decision, and it is based on the fixtures you use at once rather than the number of people in the house.
Very low flows can also cause trouble. Some units will not fire for a tiny trickle, which can leave a short burst of cold water between hot uses. A plumber can check your usage against the unit rating before you buy.
What a switch usually requires
The unit on the wall is only half the project. These are the supporting changes homeowners overlook.
| Part of the system | Gas tankless | Electric tankless |
|---|---|---|
| Fuel supply | Often needs a larger gas line than a tank heater | Needs a large dedicated circuit and breaker |
| Venting | Sealed venting through a wall or roof | None needed |
| Condensate | Condensing models drain acidic condensate to a proper drain | None |
| Water supply | Standard lines plus isolation valves for service | Standard lines plus isolation valves for service |
| Upkeep | Periodic descale, see below | Periodic descale, see below |
Scale and descaling
Mineral scale builds up inside a tankless heat exchanger and cuts its efficiency over time. Manufacturers recommend periodic flushing with a descaling solution, and installing service valves on the unit makes that job quick. A unit that is never flushed loses output and can throw error codes.
If you already own a tankless heater and it needs a flush, our crews handle that service as well. The tankless water heater page explains what a flush involves and when to schedule one.
Coconut Creek note: what is in the water
The City of Coconut Creek buys its water from Broward County, which draws from the Biscayne Aquifer and treats it at the County District 2A plant in Pompano Beach. The treatment includes softening, filtration and disinfection. The utility disinfects with chloramines.
Softened water can still leave scale, and the utility does not publish a hardness figure in its annual report. We do not guess at one. Ask the city utility for its water quality report, or test your own tap, then use that result to decide how often a tankless unit needs flushing. A home that sees heavier scale should flush more often than one that sees little.
Source: City of Coconut Creek water services page and its 2025 Annual Water Quality Report.
Is tankless a good fit for you?
A few questions settle most cases.
- Do you want to free floor space in a garage or closet?
- Is the gas line or electrical panel able to support a larger load, or will the upgrade be costly?
- Do you run several hot water fixtures at once, and does the unit you are considering cover that flow?
- Will you commit to flushing it as the maker advises?
- Is your old tank leaking or failing now? If so, a water heater replacement visit can compare both options on the spot.
Upkeep a tankless heater needs
A tankless unit has less to maintain than a tank, but not nothing. The heat exchanger can collect scale over time, and a scaled exchanger heats slowly and wastes fuel. Most makers call for a periodic flush through the service valves, and the interval depends on the model and on your water.
Keep the intake filter screen clean, keep the vent path clear and have the unit checked if it shows an error code more than once. A unit that cycles between hot and cold is telling you something, and a short visit is cheaper than a failed exchanger.
A note for nearby towns
Homeowners in Coral Springs and Margate ask us the same question, and the answer rarely changes: a tankless unit is more efficient on paper, and the real saving depends on how you use hot water.
Tankless water heater questions
In general yes, because it avoids standby heat loss. The savings depend on how much hot water you use, so a small household sees a bigger relative saving than a large one that runs hot water all day.
Not exactly. It gives continuous hot water within its flow rating. If you ask for more flow than the unit can heat, the water temperature drops.
Sometimes, but gas line size, venting and electrical capacity may need to change. We check those on a site visit before quoting.
Follow the manufacturer schedule and shorten it if your water leaves visible scale on fixtures. Service valves on the unit make the flush straightforward.
Most need power for the controls, including gas models. If you lose power in a storm, expect no hot water from them until it returns unless you have backup power.
The county plant softens the water before it reaches the city, but the utility report does not list a hardness number. Ask the utility for details or test your tap, then set the flush schedule from what you see on your fixtures.