WattCost

Data through April 2026

Running cost · Water Heaters (Electric) · ENERGY STAR certified

Lennox WHHP040T45MD240S

Heating a typical household's hot water, the Lennox WHHP040T45MD240S is certified at 915 kWh a year — about $172 at the U.S. average electricity rate, or $14.36 a month. That's 15% less than the median certified electric water heater, placing it comfortably in the efficient third of the field (198 of 566). The same unit costs $113 a year in North Dakota but $427 in Hawaii — electricity rates, not the appliance, make the difference.

Estimated annual running cost · U.S. average rate 18.8¢/kWh

$172/yr

$121 · cheapest certified water heaters (electric)$328 · priciest
Per month
$14.36
Per day
47¢
Certified use
915 kWh/yr
Type
Hybrid/Electric Heat Pump
Heat pump type
240 Volt Integrated HPWH
Storage volume
37 gal
First-hour rating
65 gal
UEF
3.55
643 kWh1,741 kWh
Where the Lennox WHHP040T45MD240S (▮) sits among all 566 certified water heaters (electric), by annual kWh

What it costs in every state

Lennox WHHP040T45MD240S: 915 kWh/yr × each state's average residential rate (EIA)
StateRate ¢/kWhThis model $/yrRelative cost
Alabama17.4¢$159
Alaska27.4¢$250
Arizona15.5¢$142
Arkansas14.2¢$130
California35.3¢$323
Colorado16.5¢$151
Connecticut32.2¢$295
Delaware18.8¢$172
District of Columbia25.4¢$233
Florida15.4¢$141
Georgia15.4¢$141
Hawaiipriciest46.6¢$427
Idaho12.7¢$116
Illinois20.5¢$187
Indiana17.9¢$164
Iowa13.9¢$127
Kansas15.8¢$144
Kentucky15.0¢$137
Louisiana14.4¢$132
Maine28.4¢$260
Maryland22.1¢$202
Massachusetts29.4¢$269
Michigan21.4¢$196
Minnesota16.4¢$150
Mississippi16.8¢$153
Missouri14.0¢$128
Montana13.9¢$127
Nebraska13.3¢$122
Nevada14.3¢$131
New Hampshire27.2¢$249
New Jersey23.5¢$215
New Mexico15.2¢$139
New York29.4¢$269
North Carolina16.3¢$149
North Dakotacheapest12.3¢$113
Ohio19.5¢$178
Oklahoma13.3¢$122
Oregon15.8¢$144
Pennsylvania21.5¢$196
Rhode Island28.3¢$259
South Carolina17.1¢$156
South Dakota14.5¢$133
Tennessee14.9¢$137
Texas17.0¢$155
Utah13.3¢$122
Vermont24.6¢$225
Virginia17.4¢$159
Washington14.4¢$131
West Virginia16.1¢$147
Wisconsin19.2¢$176
Wyoming14.7¢$134

Certified models closest in efficiency

electric water heaters within reach of 915 kWh/yr
ModelkWh/yr$/yr (US avg)
A. O. Smith HPACO-45 1**+AXST-50LBTTP 1915$172
A. O. Smith HPACO-45C 1**+AXST-50LBCTTP 1915$172
American MHPCO-45 1**+MXST-50LBTTP 1915$172
Ariston ARIHPWH-40-T915$172
Friedrich PROH50 T2 FD310BM915$172
Friedrich PROH50 T2 FD310UM915$172

Run your own numbers

Your rate, your numbers

Per day
47¢
Per month
$14.36
Per year
$172

915 kWh/yr × 18.8¢/kWh = $172/yr

Prefilled with this model's certified 915 kWh/yr — adjust if your usage differs from the DOE test basis. The certified annual kWh comes from the DOE Uniform Energy Factor test, which simulates a typical household's daily hot-water draw pattern. Only electric models (including heat-pump units) are listed — gas models burn gas, not kWh.

Questions, answered with the data

How much electricity does the Lennox WHHP040T45MD240S use?
ENERGY STAR certifies the Lennox WHHP040T45MD240S at 915 kWh per year. The certified annual kWh comes from the DOE Uniform Energy Factor test, which simulates a typical household's daily hot-water draw pattern. Only electric models (including heat-pump units) are listed — gas models burn gas, not kWh.
How much does the Lennox WHHP040T45MD240S cost to run per month?
About $14.36 a month at the U.S. average residential rate (18.8¢/kWh) — 47¢ a day, or $172 a year. Your state's rate moves this up or down; see the table above.
Is the Lennox WHHP040T45MD240S energy efficient?
It uses 15% less electricity than the median certified electric water heater, placing it in the efficient third of certified models.
What does the Lennox WHHP040T45MD240S cost to run in the cheapest vs. priciest state?
At current residential rates it costs about $113 a year in North Dakota (12.3¢/kWh) and $427 in Hawaii (46.6¢/kWh).

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