Solar Water Heater vs Electric Water Heater: Which to Buy?

At a campsite at dusk, with no outlet in sight, the question of solar water heater vs electric water heater comes down to sun or a plug. Pick a solar kettle when you have sun and no outlet, and pick an electric heater when you need hot water on demand indoors. We compared solar kettles and electric heaters on the capacity, power, weight, size and warranty terms the listings state. The Chefman electric kettle states hot water in 3 minutes, while the Rockcub solar kettle states hot water in under an hour, and the Rheem tankless unit is the only unit here with water connections stated.

SolarKitHQ earns a commission when you buy through links on this page, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Affiliate disclosure.

Solar vs electric: side by side

All numbers here are manufacturer claims from the listings, not our measurements (13 November 2026).

How the sides heat water

The solar kettles heat water with sunlight and no electricity or fuel: the Rockcub listings state to place the kettle in direct sunlight for hot water in under an hour. The electric side uses stated power instead: the Chefman kettle states 1500W and hot water in 3 minutes, and the Rheem tankless unit states 18kW at 240V with a flow rate up to 4.4 GPM. The sides solve different jobs: the solar kettles carry water to the sun, while the electric heaters need a supply and, for the Rheem, a licensed electrician should install it.

Capacity and size

Capacity is where the listings spread widest. The Rockcub solar kettles state 16.9 Fl Oz and 33.8 Fl Oz, the Chefman states 1.8L, and the Rheem states no tank capacity, only a flow rate up to 4.4 GPM. Size follows the same split: the Rockcub kettles state 4.5 by 4.5 by 21.6 inches at 2.6 pounds, the Chefman states 8.75 by 6.24 by 9.45 inches at 2.3 pounds, and the Rheem states 18.5 by 14.5 by 3.5 inches at 14.78 pounds. Match the capacity to the job: the kettles state a fixed capacity, while the Rheem heats water as it flows.

What the listings leave unclear

The Rockcub 33.8 Fl Oz kettle lists the same model, weight and size as the 16.9 Fl Oz kettle: RC500, 2.6 pounds and 4.5 by 4.5 by 21.6 inches appear on the 16.9 Fl Oz listing and on the 33.8 Fl Oz listing, which cannot describe a 16.9 Fl Oz kettle and a 33.8 Fl Oz kettle at once, so use the title capacity of 33.8 Fl Oz when you compare. The Chefman title states 1.8L while the spec table states 1.9 Quarts, the same capacity in different units. None of the listings states a water temperature figure, and only the Chefman states a warranty term, a 1-year assurance. The Rheem states a 99.8% energy efficiency class and a flow rate up to 4.4 GPM, but states no safety certification.

The kits we chose

#	Product	Solar Score	Buy
1	Chefman Electric Kettle 1.8L	9.7/10	Buy on Amazon
2	Rockcub Solar Kettle 16.9 Oz	9.6/10	Buy on Amazon
3	Rheem Tankless Electric 18kW	9.5/10	Buy on Amazon
4	Rockcub Solar Kettle 33.8 Oz	9.4/10	Buy on Amazon

1

Chefman Electric Kettle 1.8L

Chefman·9.7/10 Solar Score

i

The Solar Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A 1.8L electric kettle with 1500W power, automatic shutoff, boil-dry protection and a cETL listing, with a 1-year assurance.

Check price on Amazon

Pros

• 1500W with hot water in 3 minutes stated
• Automatic shutoff and boil-dry protection stated
• cETL listed with a 1-year assurance stated
• Cordless serving on a 360-degree swivel base with a lift-out lid

Cons

• 1.8L capacity heats a kettle at a time
• Needs a 1500W outlet, so no use without power
• Only a 1-year assurance stated
• No temperature setting is stated

Detailed Review

The listing states a 1.8L electric kettle at 1500W with hot water in 3 minutes, automatic shutoff, boil-dry protection, a cordless design on a 360-degree swivel base, blue LED lights, a lift-out lid, a stainless steel filter and a cool-touch handle. The kettle is borosilicate glass with stainless steel accents, and the listing states cETL with a 1-year assurance. It weighs 2.3 pounds and measures 8.75 by 6.24 by 9.45 inches. The title states 1.8L while the spec table states 1.9 Quarts, the same capacity in different units.

Who it's for: homes that want hot water in 3 minutes with shutoff and boil-dry protection stated. Who should skip it: anyone without a 1500W outlet or anyone who needs more than 1.8L at a time.

Its Solar Score of 9.7/10 comes from performance 30/35, build 21/25, value 21/25, safety 8/10 and warranty 3/5: 83 of 100 points, placed on our 9.2 to 9.8 scale.

Key Specifications

Capacity	1.8L
Power	1500W
Boil time	3 minutes
Weight	2.3 lb

Taken from the seller's listing on 13 November 2026. Capacity and output figures are rated by the manufacturer.

Safety and Warranty

What this listing states. Automatic shutoff, boil-dry protection and cETL stated, so safety scores 8 of 10. 1-year assurance stated. It does not say everything a buyer needs, such as who pays return shipping, so warranty scores 3 of 5. See How We Pick.

Follow the manual. Connect and use the product as the maker describes, stay within every stated rating, and read the manual before first use.

This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.

2

Rockcub Solar Kettle 16.9 Oz

ROCKCUB·9.6/10 Solar Score

i

The Solar Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A 16.9 Fl Oz solar kettle that heats water in direct sunlight with no electricity or fuel, in BPA-free materials and Vycor glass.

Check price on Amazon

Pros

• Heats water in direct sunlight with no electricity or fuel needed
• BPA-free materials and Vycor glass with 95% silica stated
• Hot water in under an hour stated
• 2.6 pounds and 4.5 by 4.5 by 21.6 inches, sized for a backpack

Cons

• Heating needs direct sunlight, so it does not work without sun
• Only 16.9 Fl Oz per fill
• No warranty term is stated
• No water temperature figure is stated

Detailed Review

The listing states a 16.9 Fl Oz solar kettle that heats water in direct sunlight with no electricity or fuel, with hot water in under an hour. The kettle uses BPA-free materials and Vycor glass containing 95% silica, stated as resistant to thermal shock and extreme temperatures. It weighs 2.6 pounds and measures 4.5 by 4.5 by 21.6 inches, and the listing names camping, hiking, power outages, tea and hot drinks as uses.

Who it's for: campers and hikers who have direct sun and no outlet. Who should skip it: anyone who needs hot water without sun or more than 16.9 Fl Oz at a time.

Its Solar Score of 9.6/10 comes from performance 28/35, build 21/25, value 20/25, safety 7/10 and warranty 0/5: 76 of 100 points, placed on our 9.2 to 9.8 scale.

Key Specifications

Capacity	16.9 Fl Oz
Weight	2.6 lb
Size	4.5 x 4.5 x 21.6 in
Glass	Vycor, 95% silica

Taken from the seller's listing on 13 November 2026. Capacity and output figures are rated by the manufacturer.

Safety and Warranty

What this listing states. BPA-free materials and Vycor glass with 95% silica, resistant to thermal shock stated, so safety scores 7 of 10. No warranty term, so warranty scores zero. See How We Pick.

Follow the manual. Connect and use the product as the maker describes, stay within every stated rating, and read the manual before first use.

This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.

3

Rheem Tankless Electric 18kW

Rheem·9.5/10 Solar Score

i

The Solar Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

An 18kW 240V tankless electric water heater with digital thermostatic control, copper immersion heating elements and a flow rate up to 4.4 GPM.

Check price on Amazon

Pros

• 18kW at 240V with a flow rate up to 4.4 GPM stated
• Digital thermostatic control with LED display and +/1 degree accuracy stated
• Two copper immersion heating elements, field serviceable, stated
• 99.8% energy efficiency class stated

Cons

• Needs 240V and 18kW, so a licensed electrician should install it
• No warranty term is stated
• No safety certification is stated
• No tank capacity is stated, only a flow rate up to 4.4 GPM

Detailed Review

The listing states an 18kW 240V tankless electric water heater with external digital thermostatic control, an LED display with +/1 degree accuracy, self-modulation that adjusts power to meet hot water demand, durable copper immersion heating elements that are field serviceable, and a flow rate up to 4.4 GPM. It states bottom 3/4 inch NPT water connections, a 99.8% energy efficiency class, 14.78 pounds and 18.5 by 14.5 by 3.5 inches. The listing states no warranty term and no safety certification, and it connects to home wiring, so a licensed electrician should install it.

Who it's for: homes that need hot water on tap at a stated flow rate and have 240V supply. Who should skip it: anyone without 240V supply or anyone who wants a portable kettle.

Its Solar Score of 9.5/10 comes from performance 32/35, build 22/25, value 20/25, safety 0/10 and warranty 0/5: 74 of 100 points, placed on our 9.2 to 9.8 scale.

Key Specifications

Power	18kW, 240V
Flow rate	Up to 4.4 GPM
Efficiency class	99.8%
Weight	14.78 lb

Taken from the seller's listing on 13 November 2026. Capacity and output figures are rated by the manufacturer.

Safety and Warranty

What this listing states. No safety listing, protection or rating is stated, so safety scores zero. No warranty term, so warranty scores zero. See How We Pick.

Follow the manual. Connect and use the product as the maker describes, stay within every stated rating, and read the manual before first use.

This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.

4

Rockcub Solar Kettle 33.8 Oz

ROCKCUB·9.4/10 Solar Score

i

The Solar Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A 33.8 Fl Oz solar kettle that heats water in direct sunlight with no electricity or fuel, listed at the same weight and size as the 16.9 Fl Oz version.

Check price on Amazon

Pros

• Heats water in direct sunlight with no electricity or fuel needed
• 33.8 Fl Oz capacity stated
• 2.6 pounds stated
• Hot water in under an hour stated

Cons

• Same 2.6 pound weight and 4.5 by 4.5 by 21.6 inch size as the 16.9 Fl Oz version, which cannot describe a 16.9 Fl Oz kettle and a 33.8 Fl Oz kettle at once
• Only the solar heating bullet is given, with no material or glass details stated
• No warranty term is stated
• No safety certification is stated

Detailed Review

The listing states a 33.8 Fl Oz solar kettle that heats water in direct sunlight with no electricity or fuel, with hot water in under an hour. It lists the same model, weight and size as the 16.9 Fl Oz kettle: RC500, 2.6 pounds and 4.5 by 4.5 by 21.6 inches. The 33.8 Fl Oz capacity comes from the title, while the weight and size figures cannot describe a 16.9 Fl Oz kettle and a 33.8 Fl Oz kettle at once, so use the title capacity when you compare. The listing gives no material, glass or warranty details.

Who it's for: campers who want the larger solar capacity and have direct sun. Who should skip it: anyone who wants stated materials or a warranty term.

Its Solar Score of 9.4/10 comes from performance 26/35, build 20/25, value 19/25, safety 0/10 and warranty 0/5: 65 of 100 points, placed on our 9.2 to 9.8 scale.

Key Specifications

Capacity	33.8 Fl Oz
Weight	2.6 lb
Size	4.5 x 4.5 x 21.6 in
Model	RC500

Taken from the seller's listing on 13 November 2026. Capacity and output figures are rated by the manufacturer.

Safety and Warranty

What this listing states. No safety listing, protection or rating is stated, so safety scores zero. No warranty term, so warranty scores zero. See How We Pick.

Follow the manual. Connect and use the product as the maker describes, stay within every stated rating, and read the manual before first use.

This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.

As an Amazon Associate I earn from qualifying purchases.

Where the points went

The Solar Score weighs performance, build, value, safety and warranty. For water heaters, safety means stated shutoff or boil-dry protection, a stated safety certification, or stated BPA-free materials; the Chefman states automatic shutoff, boil-dry protection and cETL, and the Rockcub 16.9 Fl Oz kettle states BPA-free materials. Only the Chefman states a warranty term, a 1-year assurance. How we pick explains the weights.

Scores start at 9.2 for the lowest totals and top out at 9.8. In between, a kit’s position follows its weighted points one to one in order.

Solar water heater vs electric water heater: which should you choose?

Choose a solar kettle if you have direct sun and no outlet: the Rockcub kettles state no electricity or fuel is needed, and the 16.9 Fl Oz version states BPA-free materials and Vycor glass with 95% silica. Choose the Chefman electric kettle if you need hot water in 3 minutes at home, with automatic shutoff and boil-dry protection stated. Choose the Rheem tankless unit if you need hot water on tap at a flow rate up to 4.4 GPM, and have a licensed electrician install it: the listing states 18kW at 240V with bottom 3/4 inch NPT water connections. For a shower setup at camp, see the best portable hot water heater for camping and the solar shower vs portable hot water heater guides.

Sizing Notes

• Match the capacity to the job: the Rockcub kettles state 16.9 Fl Oz and 33.8 Fl Oz, the Chefman states 1.8L, and the Rheem states a flow rate up to 4.4 GPM with no tank capacity stated.
• Match the power to the supply: the Chefman states 1500W, and the Rheem states 18kW at 240V, so a licensed electrician should install it.
• Match the size and weight to the carry: the Rockcub kettles state 2.6 pounds and 4.5 by 4.5 by 21.6 inches, the Chefman states 2.3 pounds and 8.75 by 6.24 by 9.45 inches, and the Rheem states 14.78 pounds and 18.5 by 14.5 by 3.5 inches.
• Check the stated heat time against the job: the Rockcub kettles state hot water in under an hour in direct sunlight, and the Chefman states hot water in 3 minutes.

FAQ: power away from the grid

Can a solar kettle heat water without electricity?

Yes. The Rockcub listings state no electricity or fuel is needed, just direct sunlight, with hot water in under an hour stated.

How fast does the Chefman electric kettle boil water?

The listing states hot water in 3 minutes at 1500W.

Which of these water heaters states a warranty?

Only the Chefman, with a 1-year assurance stated. The Rockcub kettles and the Rheem state no warranty term.

Do the Rockcub kettles state the same weight?

Yes. The listings state 2.6 pounds and 4.5 by 4.5 by 21.6 inches for the 16.9 Fl Oz kettle and for the 33.8 Fl Oz kettle, which cannot describe a 16.9 Fl Oz kettle and a 33.8 Fl Oz kettle at once.

Does the Rheem tankless heater need an electrician?

Yes. The listing states 18kW at 240V, so a licensed electrician should install it. The listing gives no wiring steps.

Still deciding? Our top pickChefman Electric Kettle 1.8L

Check price on Amazon

Related solar guides

See every Solar Lights, Cameras and Fans guide. For camping water, see the best solar shower for camping and the best RV hot water heater for solar. Also see our how long does electric water heater last.

More picks: portable camping shower with water heater, solar shower, gas camping shower.