Investor · N.E. Illinois · Member since 2019 · 49 posts · 39 votes
Does anyone have thoughts on tankless electric vs. traditional electric water heaters in the 3 to 5 gallon range. Our use is usually just a single sink in a bathroom, but occasionally tenants want/have a slop sink in the shop/warehouse portion of the unit (multi tenant industrial small bay). We are thinking it would be less electrical usage since there would be no need to keep a tank hot 365 days a year for sporadic and small hot water usage (some tenants are only at the units to load up in the morning and unload in the evening). But we've only had experience with the small volume tank heaters.
Realtor · Willow Grove, PA · Member since 2017 · 979 posts · 643 votes
10mo
Traditional 3–5 gallon tank heaters are simple and cheap, but they keep water hot constantly, which wastes energy if usage is infrequent. Tankless may cost more upfront and could require higher electrical capacity, but for occasional single-sink use in multi-tenant industrial units, it’s likely the more efficient choice.
Realtor · Willow Grove, PA · Member since 2017 · 979 posts · 643 votes
10mo
Traditional 3–5 gallon tank heaters are simple and cheap, but they keep water hot constantly, which wastes energy if usage is infrequent. Tankless may cost more upfront and could require higher electrical capacity, but for occasional single-sink use in multi-tenant industrial units, it’s likely the more efficient choice.
Real Estate Agent · Columbus OH · Member since 2018 · 1k+ posts · 1k+ votes
10mo
cant speak to your specific use but have an on demand heater in my personal home and really love it. if the usage is sporadic I'd think there would be a break even point on the upfront cost of the on demand vs the electric usage on the traditional one.
Investor · Collierville, TN 38017 · Member since 2017 · 635 posts · 458 votes
10mo
For a single sink with sporadic use, electric tankless sounds good on paper but is usually the wrong choice in small-bay industrial units.
A 3–5 gallon traditional electric tank almost always wins for reliability, cost, and tenant behavior.
Here’s why:
1. Tankless electric requires huge amperage nobody talks about
Even the small-point-of-use electric tankless units often need:
40–60 amps on a dedicated breaker
#6 or #8 wire
Panel capacity you may not have in older industrial bays
By the time you upgrade the circuit, wiring, and breaker space, any “energy savings” are gone.
The electrical requirements are usually the deal-breaker.
2. Tankless units hate inconsistent, on/off demand
Your exact use-case, slop sink, occasional washups, random tenant usage, is where electric tankless performs the worst:
Rapid cycling burns out the heating elements
Slop sinks often have low flow, and tankless units won’t even turn on under ~0.5–0.7 GPM
Flow rate varies a lot with industrial faucets, and tenants twist knobs fast
You end up with “lukewarm water” complaints or units that won’t fire consistently.
4. A 3–5 gallon tank heater is cheap, tough, and works every time
The small tanks:
✔ Use very little power
✔ Plug into standard 120v or small 240v
✔ Cost $150–$250
✔ Are easy to replace
✔ Heat water fast
✔ Require no fancy wiring
✔ Don’t care about flow rate swings
Even though they keep water hot all day, the total kWh usage is tiny because the water mass is so small.
For sporadic sink usage, the cost difference on your electric bill is negligible.
