Best Water Heater for a Family of 6
At six people you are choosing between a very large tank, very fast recovery, or no tank at all.
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Six people need 90 gallons or more in the peak hour, which is past what a single conventional tank comfortably delivers. The three honest answers are gas tankless (unlimited sequential showers), a 66 gallon heat pump rated at 83 gallons in the first hour, or an 80 gallon electric tank plus a staggered schedule.
At six people the arithmetic stops being about picking the right tank and starts being about choosing a strategy. Five showers plus appliances inside a single hour is roughly 90 to 100 hot gallons, and no residential storage tank delivers that from a cold start without either a very large volume or a very large burner.
The three strategies
Strategy 1: stop storing, start flowing (gas tankless)
The cleanest answer to "we keep running out" is a unit that cannot run out. A 199,000 BTU condensing tankless heater delivers 5.5 GPM at a 70°F rise indefinitely — five sequential showers, or two simultaneous ones, all morning. For a six-person household the usage pattern is almost always sequential, which is exactly what tankless handles best.
What it costs you: a gas line sized for the unit, condensate drainage, an annual descale, and a conversion job rather than a swap. If your gas supply already feeds a large furnace and a range, the line may well be adequate. Best tankless water heaters.
Strategy 2: a big heat pump (66 to 80 gallons)
A 66-gallon heat pump water heater rated at 83 gallons in the first hour serves six people on a normal day, and at a 3.84 UEF it does so at roughly a quarter of the electricity of a resistance tank. For a six-person all-electric household the running-cost saving is the largest of any decision on this site, because the volume of hot water is large.
The conditions are the usual ones and they are not negotiable: air volume, a condensate drain, and somewhere the compressor noise and the cooling effect are welcome rather than a nuisance. Heat pump water heaters in a garage or basement.
Strategy 3: 80 gallons of resistance plus a schedule
An 80-gallon electric tank is rated at about 78 gallons in the first hour. That is short of a six-person peak hour, so this strategy only works with staggered draws. It is the cheapest to buy and the most expensive to run, and it is the right answer when the install space rules out a heat pump and there is no gas.
| Option | Delivery | Running cost | Install burden |
|---|---|---|---|
| Gas tankless, 199,000 BTU | 5.5 GPM at a 70°F rise, unlimited | Low per gallon; gas rates | High — gas line, venting, condensate |
| 66 gal heat pump | 83 gal first hour | Lowest of the three | Medium — space, air volume, condensate |
| 80 gal electric resistance | 78 gal first hour | Highest | Low — like-for-like swap if it fits |
| Two 50 gal tanks in series | Effectively doubles storage | Doubles standby loss | High — space for two units |
Quick picks
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| # | Product | Best for | Price |
|---|---|---|---|
| 1 |  Rheem Prestige RTGH-95DVLNThe condensing gas tankless most houses should start with: 5.5 GPM at a 70°F rise covers two showers in a cold-inlet climate, and the 12-year residential heat exchanger warranty is the longest on this list. | Most whole-house gas jobs | Check price on Amazon No live price feed on this site, so we show none. #ad |
| 2 |  A. O. Smith Voltex MAX, 66 galAn 83-gallon first-hour rating at a 3.84 UEF — the heat pump water heater for a household that runs several showers back to back and still wants the running cost of a heat pump. | Largest first-hour rating | Check price on Amazon No live price feed on this site, so we show none. #ad |
| 3 |  Rheem Professional Classic 80 gal electricThe big resistance tank: 80 gallons of storage and a 78-gallon first-hour rating, which is how you cover a six-person household when gas is not an option and a heat pump will not fit. | Large households on electric only | Check price on Amazon No live price feed on this site, so we show none. #ad |
What we would buy for six people
Pick 1 — Most whole-house gas jobs
Rheem Prestige RTGH-95DVLN
The condensing gas tankless most houses should start with: 5.5 GPM at a 70°F rise covers two showers in a cold-inlet climate, and the 12-year residential heat exchanger warranty is the longest on this list.
| Fuel | Natural gas (LP variant sold separately) |
|---|---|
| Gas input | Up to 199,900 BTU/h |
| Flow at a 70°F rise | 5.5 GPM |
| Maximum flow | 9.5 GPM at a 35°F rise |
| Efficiency | Up to 0.93 UEF, stainless condensing heat exchanger |
| Minimum activation flow | 0.4 GPM |
| Venting | Up to 150 ft of 3-inch PVC; 60 ft of 2-inch PVC |
| Dimensions | 18-1/2 in W x 9-3/4 in D x 27-1/2 in H |
| Warranty | 12-year heat exchanger (residential), 5-year parts, 1-year labor |
What is good
- The 70°F-rise figure is published, so you can size it honestly instead of guessing from the headline number
- Condensing design vents in PVC, which is far cheaper to run than stainless category III pipe
- 0.4 GPM activation means a trickle at a bathroom faucet still fires the burner
- Long PVC vent runs let you put it where the gas line already is
What is not
- Needs a gas line sized for nearly 200,000 BTU/h — many existing 1/2-inch runs are not
- Condensate has to go somewhere, which means a drain or a condensate pump
- Annual descaling is not optional on hard water
Skip it if: Skip it if your gas meter and line cannot carry 199,900 BTU/h. Upsizing the gas line is often the single largest cost in a tankless conversion, and no amount of unit quality fixes a starved burner.
No live price feed on this site, so we show none. #ad
Specifications above from Rheem RTGH series specification sheet (PDF); Pace Supply listing, RTGH-95DVLN, 199 kBtu/hr. We have not tested this unit ourselves.
Pick 2 — Largest first-hour rating
A. O. Smith Voltex MAX, 66 gal
An 83-gallon first-hour rating at a 3.84 UEF — the heat pump water heater for a household that runs several showers back to back and still wants the running cost of a heat pump.
| Capacity | 66 gallons |
|---|---|
| First-hour rating | 83 gallons |
| Efficiency | 3.84 UEF |
| Certification | ENERGY STAR certified |
What is good
- 83 gallons in the first hour beats an 80-gallon resistance tank
- 3.84 UEF is still roughly four times a resistance tank
- 66 gallons of storage plus fast recovery is the combination big households actually need
- ENERGY STAR certified for rebate eligibility
What is not
- Lower UEF than the Voltex AL at the same capacity — you are trading some efficiency for delivery
- Large footprint
- Wholesale distribution
Skip it if: Skip it if two people live in the house. You would be buying 66 gallons and an 83-gallon first-hour rating to serve a demand a 50-gallon unit covers, and paying standby losses on the difference every day for a decade.
No live price feed on this site, so we show none. #ad
Specifications above from First Supply listing, A. O. Smith HPTA-66 Voltex MAX. We have not tested this unit ourselves.
Pick 3 — Large households on electric only
Rheem Professional Classic 80 gal electric
The big resistance tank: 80 gallons of storage and a 78-gallon first-hour rating, which is how you cover a six-person household when gas is not an option and a heat pump will not fit.
| Capacity | 80 gallons |
|---|---|
| First-hour rating | 78 gallons |
| Elements | 4.5 kW, 2 elements |
| Voltage | 240 V |
| Efficiency | 0.93 UEF |
What is good
- Storage volume does the work that electric recovery cannot
- 78 gallons in the first hour genuinely covers four back-to-back showers
- Simple: two elements, two thermostats, parts available everywhere
- Nothing to service annually
What is not
- Physically large — it will not fit where a 50-gallon tank fit
- 80 gallons of standby loss, every hour of every day
- First-hour rating is lower than its own capacity, which tells you how slow the recovery is
Skip it if: Skip it if the space is tall enough for an 80-gallon heat pump model. You are choosing the version of the same tank that costs roughly three times as much to run, for no gain other than a lower sticker price.
No live price feed on this site, so we show none. #ad
Specifications above from Ferguson listing, Rheem Professional Classic 80 gal electric. We have not tested this unit ourselves.
What about two tanks?
Plumbing two tanks in series genuinely works and is common in large households — the first tank preheats, the second finishes. It roughly doubles your first-hour delivery. It also doubles your standby loss, doubles the number of anode rods and drain valves you maintain, and needs the floor space and the fuel supply for both. We would reach for tankless or a large heat pump first, and consider a second tank when the install space rules both out.
The free capacity nobody uses
- Low-flow shower heads. With five or six showers a day this is the highest-leverage change in the house: roughly 30% off every shower's hot-gallon figure.
- Stagger by 30 minutes. With a 21 gallon-per-hour recovery rate, half an hour between showers is about 10 extra gallons of hot water.
- A mixing valve with a higher storage temperature. More usable hot water from the same tank. Fit it properly, because it raises scald risk if you do not.
- Run laundry and the dishwasher outside the peak hour. Those two draws are entirely schedulable and they are competing with your showers.
What goes in with it
A water heater is a system, not a box. These are the parts that go in with it, and the ones people discover they need halfway through the job.
- Expansion tank
Required by code on a closed system, which is most homes with a pressure-reducing valve.
- Drain pan
Cheap insurance anywhere the tank sits above something you care about.
- Anode rod
The part that decides when the tank leaks. Replacing it is the highest-value hour of maintenance there is.