How
to save money with two
water heaters
Applies to gas and electric water heaters
Series connection
purpose: twice as much hot water
Be sure to insulate pipes
Be sure to insulate pipes
Water heaters in series:
Hot water from #1 water heater feeds into #2
Purpose: Twice as much hot water available.
Heater #1 works more and will not last as long.
Heater #2 works less because it is used as storage heater.
How to control cost:
1) Turn off heater #1 and save $40 per month
2) Use heater #1 as tempering tank to passive raise temperature to ambient room temperature Read more
3) Install timer on heater #1 or both heaters Compare timers
4) More ideas: Insulate pipes, Insulate water heaters, Turn down thermostats, etc Read 9 ways to save
How much does it cost to operate water heaters
Electric:
See electric wiring options for adding second tank without adding second wire and circuit breaker
Gas:
When adding second gas water heater, total BTU of both heaters must be calculated. Call local gas company Read label on side of each tank for BTU rating. For example both heaters together 100,000 BTU, and gas pipe length is 80 feet, then 3/4" pipe is needed. Chart
How to install gas water heater
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Correct plumbing saves money
Applies to gas and electric water heaters
Insulate pipes
Heat traps slow convection loss. Minimum 6" drop.
Jumper ground wire stops stray current corrosion
Di-electric connections to protect water heater and pipes
Read 9 ways to save
Parallel water heaters supply hot water to different usage points
Be sure to insulate pipes
Be sure to insulate pipes
Cold water feeds into both water heaters
Purpose: Different areas of house served by different water heater
Heaters #1 and #2 last as long as each other.
How to control cost:
1) Identify which faucets receive hot water from each water heater.
2) See if pipes can be connected to one water heater shown in illustration below.
3) Use countertop pot heater. Use under-counter water heater at local sink.
How to install under-counter water heater
4) Install timer on less-used water heater.
Compare timers
5) Reduce thermostat on less-used water heater
See how to adjust temperature
6) Insulate pipes, Insulate water heaters, Turn down thermostats, etc
Read 9 ways to save
 Pot heater |  Under-counter heater |
Pot heater
Under-counter heater can reduce need for larger water heater.
How to install under-counter water heater
Convert parallel to series means one water heater can be turned off
Be sure to insulate pipes
Be sure to insulate pipes
Advantage:
Turn off heater #1 and save $40 per month
Use heater #1 as tempering tank Read more
Install timer on heater #1 Compare timers
Tempering tank, or staging tank can pre-heat cold incoming water in winter
Tempering tank located in naturally warm location can preheat water before it flows into cold water side of water heater.
Buy scratch-n-dent water heater
Use old water heater as tempering tank
Flush with water and 2 pints hydrogen peroxide.
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How to wire thermostats and elements
How to troubleshoot electric water heater
Ready for peak electric prices?
How-to-wire-water-heater-with-switches-and-timers
How to wire off-peak water heater thermostats
Timer
for two electric water
heaters
 |
 FM1 timer with 15 minute intervals or 7-day timer with 2 hour intervals |
Works for two 4500 watt water heaters
Compare more timers
Intermatic timers and manuals
120V 208-240V 277V
Skip-a-day
WHQ series sell sheet
24-hour timer
WHQ4 sell sheet
7-day timer
WHQ7 sell sheet
Many ways to control two electric water heaters
This is not a two-channel timer, so each water heater will operate on same time schedule
Look at water heater label for tank wattage: Label shows total connected wattage
Use 40 amp circuit breaker and 8 gauge wire from breaker box
Use 8 gauge wire between timer terminals
Use 8 gauge or smaller 10 gauge wire to each water heater
Do not mix different gauge wires under same screw terminal or smaller gauge wire can come loose and become fire hazard.
When heater #1 is ON, heater #2 is OFF
Control
each water heater
with different schedule
Compare Box-type water heater timers
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Each water heater can have different 7-day schedule
10 gauge wire and 30 amp breaker run cooler.
30 amp circuit breaker and 10 gauge wire for water heater runs cooler with less energy loss. Breaker box lasts longer.
Different wiring:
For two 4500 watt water heaters, you can use one 40 amp breaker and 8 gauge wire to bring power from breaker box to the first timer.
For two 5500 watt water heaters, you can use 50 amp breaker and 8 gauge wire
Water heater timers
EH40 water heater timer
Things you can do to increase amount of hot water
9 ways to save with water heater
How to increase amount of water:
Adjust thermostat to higher temperature. How to adjust thermostat
Install shower timer so more people can shower before hot runs out.
Install low flow shower heads and areators so hot lasts longer.
Take showers instead of bath. Shower uses 5-9 gallons hot water, bath uses 12-15 gallons
Take showers in quick succession so hot water located at top of tank does not cool when incoming cold water arrives.
Install larger water heater tank.
Install two tanks. Two water heaters
Install under-counter water heater at sinks.
Install insta-hot faucet in kitchen.
Use pot boiler at kitchen sink.
Leave gallon jugs of water in sun during day for hot water needed at lunch or dinner.
Install solar water heater in addition to other sources. Solar water heater
Install tempering tank next to regular tank to passively preheat incoming cold water in winter. Tempering tank
Electric: convert elements from non-simultaneous to simultaneous operation. requires additional circuit breaker and wire to heater, and rewire of heater. Simultaneous wiring
Install mixing valve so some usage points receive warm water while others receive hotter water.
Do not turn on hot water when using cold water. Single handled faucet lifted straight up will cause cold water to immediately enter tank. Crossover
Turn off hot water to washing machine.
Wash dishes by hand.
Install dishwasher on cold water line instead of hot.
Reduce water pressure in house using pressure reducing valve. Turn down water well pressure. Hot water lasts longer. Plumbing pipes and fixtures last longer.
Clean restrictions in pipes. Low hot water pressure
Shorten distance from hot water tank to usage point. Distance hot water travels in 30 seconds
Gas water heater: install external air intake so ambient room temperature is not lowered in winter when combustion draws cold air through cracks and doors.
Install water heater with higher recovery rating, and higher first-hour delivery.
Clean sediment out of tank to increase efficiency. How to remove sediment/ efficiency numbers
Insulate water pipes throughout house. Insulate water heater .Read 9-ways to save with water heater
Water heater safety precautions
