- Water Heaters
- Water heaters
- Sizing
- 6-minute read
The tankless vs tank water heater decision looks different in January than on the showroom floor. Cold Lake Michigan inlet water, hard well water and older gas lines all change the math for Racine County homes.
In a Wisconsin winter a tankless unit must raise incoming water from roughly 40°F to 110°F — a 70°F rise — which cuts its rated flow by about half: a unit sold as 7 gallons per minute delivers closer to 3.5–4 gpm in January. Size it for the winter rise, or keep a well-sized tank.
- ★ 4.8 · 51 Google reviews
- WI Master Plumber License #225457
- Two Master Plumbers on staff
- Free estimates
Key takeaways
- Flow ratings on the box assume warm inlet water; southeastern Wisconsin inlet water is far colder from December through March.
- A tank does not care about inlet temperature for capacity — it stores hot water and recovers between uses.
- Hard water is the other Wisconsin variable: a tankless heat exchanger on well water needs descaling on a schedule, or a softener ahead of it.
- Gas supply, venting and the permit are where a tankless conversion adds cost; a like-for-like tank swap avoids all three.
How does winter change the tankless vs tank water heater comparison?
A tankless unit heats water on the fly, so the bigger the temperature rise it has to deliver, the lower its flow rate. A tank heats slowly and stores the result, so inlet temperature only affects recovery time.
Lake Michigan water arriving at a Racine home in January can be near 40°F. Well water in the county runs a little warmer but still far below the 60–70°F many manufacturers use for headline ratings.
| Inlet water | Rise to 110°F | What a “7 gpm” tankless actually delivers |
|---|---|---|
| 70°F (rating condition) | 40°F | About 7 gpm |
| 55°F (Racine, spring/fall) | 55°F | About 5 gpm |
| 40°F (Racine, deep winter) | 70°F | About 3.5–4 gpm |
Those figures come from the flow-versus-rise curve every manufacturer publishes for its units; check the exact curve for the model you are quoted rather than the number on the front of the box.
What does 3.5 gpm mean for a real household?
A standard showerhead uses about 2 gpm and a kitchen faucet 1.5–2 gpm. In winter, one unit sized off the summer rating supports one shower and not much else.
One or two people
A correctly sized single tankless works well. Endless hot water for one shower at a time is exactly what it is good at.
Family of four or five
Either a larger tankless sized for the 70°F rise, two units in parallel as in the photo above, or a 50-gallon tank that handles back-to-back showers without thinking about flow.
Soaking tub or multi-head shower
A tank, or a tankless plus a small buffer tank. Filling a 60-gallon tub at 3.5 gpm takes 17 minutes of continuous burn.
Which one handles Racine County hard water better?
Neither loves it, but they fail differently. Racine city water tested at 140 ppm (about 8 grains per gallon) in the 2025 Water Quality Report. Private wells in Caledonia, Franksville, Waterford and Burlington are commonly much harder. Brookfield's municipal wells and Burlington's deep-sandstone supply run harder still, which is why tankless installs in Brookfield and water heater replacements in Burlington both get a softener first.
In a tank, minerals settle on the bottom and cause the popping covered in the water heater noise guide. In a tankless unit they coat the narrow heat exchanger passages, which raises the exhaust temperature and eventually throws an error code.
- Tank on city water: flush yearly. On a well, every six months.
- Tankless on city water: vinegar descale yearly through the isolation valves installed at the unit.
- Tankless on a well: install a softener or scale-inhibitor ahead of the unit, as PM did on the twin installation pictured above, or plan on descaling twice a year. That is the Waterford water heater conversation on nearly every lake-parcel install.
Why is converting to tankless more than the unit price?
A tankless burner is three to four times larger than a tank's. That drives three changes to the house that a like-for-like tank swap never touches.
Gas line sizing
A 40-gallon tank burns around 40,000 BTU/hr; a whole-house tankless can burn 150,000–199,000. Many Racine homes need the gas line upsized from the meter.
Venting
Tankless units vent through PVC or stainless, usually out a side wall. The old metal flue is abandoned and the chimney may need a liner for the furnace it was sharing.
Condensate and electrical
Condensing units drain acidic condensate to a neutralizer and a drain, and need a 120-volt outlet. Tanks need neither.
Permit and inspection
Both types need a City of Racine plumbing permit; the tankless inspection has more items on it. See the Racine water heater permit guide.
Deciding on tankless vs tank water heater options for a Racine home? PM sizes off the winter inlet temperature and your fixture count, not the box rating. Free estimates.
Call (262) 770-0039Request serviceWhen does a tank still win outright?
Emergency replacement
A leaking tank on a Friday gets replaced by a tank. Tankless conversions are planned jobs with gas, vent and electrical work.
Tight budget, short horizon
If you expect to sell within a few years, the lower installed cost of a tank recovers faster than tankless fuel savings.
Big simultaneous demand
Two teenagers, a soaking tub and a dishwasher running at once is what a 50- or 75-gallon tank is built for.
A tankless unit wins on floor space, on a long service life when it is descaled, and on standby losses. Whichever way the tankless vs tank water heater question lands for your house, PM's water heater service in Racine installs and services both.
Questions Racine homeowners ask about tankless vs tank water heater choices
Does a tankless water heater work in a power outage?
No. Gas tankless units need electricity for the controls and fan. A gas tank with a standing pilot keeps heating during an outage, which matters in a Wisconsin ice storm.
Can I put a tankless water heater where my tank is now?
Usually, provided a vent can reach an outside wall within the manufacturer's length limit and the gas line can be upsized. Basement corners far from an exterior wall are the awkward ones.
How long does each side of the tankless vs tank water heater question last?
Tanks commonly run 8–12 years in this area, less on hard well water without flushing. Tankless units are built for a longer service life, but only when they are descaled on schedule.
Are tank water heaters being phased out?
No. Federal efficiency rules push larger electric tanks toward heat-pump designs, but gas and electric tanks stay on the market. The downsides of tankless — winter flow loss, gas-line and venting work, no hot water in an outage — are why many plumbers still recommend a tank for the right house.
Further reading on sizing and replacement
The lifespan guide covers whether your current tank is due; the permit guide covers what the city will inspect on either type.
Tank or tankless, sized for a Wisconsin January. Free estimates, city permit included, two Master Plumbers on staff. Searching "plumbers near me Racine" from anywhere in the county lands on the same two names.
Call (262) 770-0039Request service- City of Racine, 2025 Water Quality Report (hardness 140 ppm): media.cityofracinewi.gov