Best Compact Water Heaters in 2025

CONTINOUS FLOW – Hot showers will never be interrupted again. Enjoy continuous, on-demand hot water with an unlimited supply, when you want it without wasting any energy when not needed

SPACE & ENERGY SAVER – Its small, sleek white design saves space yet still provides endless hot water for your whole house, and no venting is required. Eco friendly unit saves energy with auto-modulation

SILENT OPERATION – One electronic switch will activate the hot water heater and it’s noise free while in use. Digital temperature display is easy to read, while the interior solid copper heating system does all the power work

Original Design: Tankless hot water heater only heats when necessary to conserve energy; For the latest in non-condensing technology and a cleaner layout that speeds up service and installation, check out our new RE160iP model

Never Run Out of Hot Water with this Compact Propane Water Heater: Non-condensing tankless hot water heater from Rinnai is only the size of a small suitcase and fits in a wide variety of spaces, but provides up to 6.5 GPM (5 fixtures at once)

Smart, Durable Design: Enhanced scale detection helps prevent serious, long-term damage to unit; Includes 15-, 5-, and 1-year residential guarantee for heat exchanger, labor, and parts, respectively; See Controlr module for WiFi control (not included)

POWERFUL PERFORMANCE — At 42,000 BTUs, this continuous hot water heater provides optimal performance for RV plumbing. The quiet, brushless motor runs on 12V power that operates at less than three amps for a nearly noiseless operation

CONSISTENT TEMP — The onboard microprocessor monitors incoming cold water temperature, flow rate and outgoing hot water temperature to maintain a steady water flow. It also regulates the burner to maintain a consistent temperature, preventing cold spots and scalding water

HIGHLY EFFICIENT — The Girard RV tankless water heater consumes half the LP gas that a six-gallon tank water heater would consume for the same amount of hot water

Compact design; wall or floor mounted (wall bracket included)

Provide immediate hot water at the point of use; install as booster or standalone

Easy installation; installs right at the point of use with water connection and standard 110/120 Volt outlet

Superior Safety and Enriched Ambiance: The fish tank heater is constructed with high-quality shatterproof glass and BPA-free plastic, ensuring a safe habitat for your fish. Aquarium heater 50W, power cord 4.75ft, designed for most fish tanks, recommended for aquariums up to 100 Gallons.

Precision in Temperature Control: This aquarium heater excels in providing a customizable temperature range of 68°F-93°F, catering to various aquatic species. Suitable for freshwater and saltwater tanks, it creates a natural environment for your finned friends.

Compact, Versatile, and Efficient: Whether you have a small aquarium heater 5-gallon tank or an aquarium heater 55-gallon setup, this compact heater can be placed horizontally or vertically. Position near a filter or pump for even heat distribution.

【Super Mini Size, 50Watt for 3-10 Gallons】 YukiHalu 50W aquarium heater is designed for 3-10 gallons mini fish tank. Compact design, take less space in the fish tank, easy to hide in the tank. Temperature can be accurately adjusted from 64 to 93°F. This heater suitable for both saltwater and freshwater. The rated voltage is 100-130V.

【Automatic Constant Temperature with 1℉Accuracy】Thanks to advanced Intelligent Frequency Conversion Technology, the water temperature can be kept constant with an accuracy of 1℉. The heater's working frequency will be changed according to temperature variation, and the heating is automatically stopped when the set temperature is reached. Compare to traditional heater, this new technology will cut down 49% electricity bill for you.

【Overheating Protection, Out of Water Protection】The power will be cut off and stop heating automatically if the heater out of water or overheating. Protect your fish. Never cook your fish. 30days full refund, 12-months warranty.

Saving Energy & Money- Under sink water heater built-in insulation foam, reduce heat loss

High-Quality - Small water heater has a glass-lined tank, anti-scaling, has a long service life, and is easy to maintain

Safety - UL certification, high-temperature power-off protection (Max. water pressure is 150 PSI, T& P relief valve included)

Original Design: Tankless hot water heater only heats when necessary to conserve energy; For the latest in non-condensing technology and a cleaner layout that speeds up service and installation, check out our new RE180iP model

Never Run Out of Hot Water with this Compact Propane Water Heater: Non-condensing tankless hot water heater from Rinnai is only the size of a small suitcase and fits in a wide variety of spaces, but provides up to 7.5 GPM (5 fixtures at once)

Smart, Durable Design: Enhanced scale detection helps prevent serious, long-term damage to unit; Includes 15-, 5-, and 1-year residential guarantee for heat exchanger, labor, and parts, respectively; See Controlr module for WiFi control (not included)

Lightweight, Compact & Portable Design: The 10 pounds lightweight portable water heater's folding handle keeps it out of the way and enables easy setup outside.

Flow Rate & Temperature Specification: The temperature raise is 114.8℉ (46℃) at its highest point and 46.4℉ (8℃) is at its lowest point of 1.32 GPM. Also, 1.32 gallons of hot water can be produced per minute at the flow rate of 1.32 GPM.

Versatile Applications: The lowest water pressure at beginning for the water heater is 3.0 PSI. For off-grid and rural areas, this hot water generator powered by two size D batteries is ideal. No more chilly outdoor shower anymore.

Original Design: Tankless hot water heater's Circ-Logic technology offers recirculation patterns that match your habits; For the latest in non-condensing technology that speeds up service and installation, check out our new RE160iP model

Never Run Out of Hot Water with this Compact Propane Water Heater: Non-condensing tankless hot water heater from Rinnai is only the size of a small suitcase and fits in a wide variety of spaces, but provides up to 7.5 GPM (5 fixtures at once)

Smart, Durable Design: Includes 12-, 5-, and 1-year residential guarantee and 5-, 5-, and 1-year commercial factory warranty for heat exchanger, labor, and parts, respectively; See Controlr module for WiFi control (not included)

Tank less water heaters provide a continuous Supply of hot water and only heats the water you need, when you need it

Instant, consistent and endless hot water

The most advanced, self-modulating technology available, meaning the unit will adjust how much energy needs to be input based on how much hot water is needed

Preset temperature has been set to 77°F, appropriate for most tropical fish, shrimp and aquatic plants requiring stable conditions

With accuracy of ±2°F and overheat protection, protect your tank from extreme temperature

LED indicator light will turn to red when the heater is actively heating

Endless Hot Water: Enjoy unlimited hot water flow throughout the house; compact, durable, and easy to install; professional installation recommended

Energy and Space Efficient: Space-saving design conserves energy as it heats only when necessary

Optimal Water Pressure: High-performance up to 5.3 GPM hot water flow rate for a powerful, constant stream

【ETL & UL CERTIFIED SPACE HEATER】This portable space heater is made from flame-retardant materials. With ETL and UL certification, this space heater is safe and reliable. The ceramic heater has OVERHEAT and TIP-OVER protection, it will automatically shut off if the temperature exceeds the limit value or is knocked over accidentally and back to work once it gets to a safe temperature inside or stands safely again.

【2 SECONDS WARM-UP】With PTC ceramic heating technology, 1500W output, and high-speed fan, this electric heater put out tons of heater to heat up 108 sq. ft. in seconds and produces no red light or flame. Angled legs make heat distribution wider and allow air to blow upwards. It's quiet enough to use in a bedroom while sleeping. Your ideal personal heater to keep your room cozy and get good sleep through the harsh winter.

【ADJUSTABLE THERMOSTAT】This small space heater features an adjustable thermostat control dial, easily preset the thermostat within the range of 41°F - 95°F. Always keep your room temperature at the most optimal level and reduce your power consumption. The electric heater is perfect for living rooms, bedrooms, studies, offices, garages, etc.

HEATS FAST + SIMPLE TO USE: You’ll have warm water in seconds, boiling water in just minutes. Fill your container, place the immersion heater in the liquid, then turn on the immersion heater. It’s that simple.

MAXIMUM SAFETY: Durable burn guard protects your coffee mug, cups, and bowls ensuring the coils never touch the sides of your dishes or containers. Safely heat coffee, tea, soup, hot chocolate, and more.

TRAVEL ADAPTER: Powered with a dual voltage system, (120 V for North America, and 240 V for Europe and other regions), and includes a European adapter and travel pouch; perfect for all your domestic and international travel needs

CSA Safety Standard -CSA safety standard approved portable tankless water heater,flame failure device, anti-freezing protection, over heating protection to ensure the family safety. Automatically decrease water pressure between 3.0-110 PSI. The anti-freezing drain plug can discharge the residual water to avoid freezing in cold areas or in case of long time no use. The water heater will shut off automatically when high water temperature protection over 176 °F.

Lightweight Portable Design-Compact size weights 10 lbs with portable handle for easily carry. Hang it using the mounting bracket on the top/back of the gas water heater. It only takes you a 15 minutes to install the propane water heater.

Instant Hot Water- Maximum power output 28,000btu/hour, you can get 1.32 gallons instant endless hot water easily wherever you are. No need to preheat before operating the tankless water heater. As soon as you turn on the tap, the water flows with your desired temperature.

🐟HITOP Compact size aquarium heater 200W with controller, suitable for seawater and freshwater heating, betta fish and turtle tanks and other small fish tanks 25-50 gallon.

🐟Easy to operate: This fish tank heater is easy to use, 6Ft long cable wire and the external controller can easily set the temperature, and the temperature adjustment range is 68-93℉.

🐟Easy to read temperature: The controller of this heater has Digital LED temperature display, which can display the real-time water temp and set temp, so that you can know the temperature changes in the fish tank easily. There is also a clear heating indicator on it.

SAFETY - Designed for safe guarding both heater and your aquarium.

DETACHABLE - Multi-section detachable design, you can adjust the length at will.

COMPACT SIZE - With three suction cups which are quite convenient for you to install in tank.

1.58 GPM Hot Water Heater -Rated at 1.58 GPM, this on demand water heater provides endless hot water on demand, it’s more efficient and energy-saving, saving up to 98.95 % on water heating costs

Versatile Applications: The lowest water pressure at beginning for the water heater is 3.0 PSI. For off-grid and rural areas, this hot water generator powered by two size D batteries is ideal. No more chilly outdoor shower anymore

Easy & Safety Installation- Camplux BW158G heater comes with 1-year guarantee, 5 feet premium on/off shower head, 5 feet gas regulator, 1 set US-standard garden hose, and 1 installation hardware pack. Setting up this propane water heater simply takes 10 minutes

【Wider Heating & Advanced Heating Tec】Our infrared heater indoor outdoor is 42 inches high, and its heating tube is about two-thirds of its high, which can warm you and your family up from the feet to the whole body. This 1500-watt outdoor heater for patio features high-efficiency carbon fiber heating wire and offers instant & focused sunshine-like heat, directly transfers heat to the body so you can feel comfortably warm instantly, no need to wait in the cold for a long time.

【9 Optional Heat Levels】This electric indoor outdoor heater for patio is available in 9 heat modes, from 620W to 1500W, perfectly customized to meet your desired temperature that makes you feel nice and warm in the cold environment. The outdoor patio heater electric boasts a compact, space-saving design, making it ideal for outdoor or indoor use.

【1-9 Hours Timer】The timer function of Haimmy outdoor electric heater allows you to set a duration you need from 1-9 hours before going to sleep to prevent potential safety hazards and save energy. In winter, infrared patio heaters will be good company in a quiet way. The infrared space heater works silently since they don't use a fan - they just heat light! They're great for noise-sensitive environments to accompany you to sweet sleep and better work. Set the timer on the remote or press & hold the knob for 2s to enter/exit the timer setting.

Portable, Lightweight Design: This portable water heater weights only 10 pounds and comes with folding handle keeps it out of the way and enables easy setup outside

Simple, Easy Hot Showers: The camplux portable hot water heater is easy to set-up. All you need is the water heater, gas bottle away you go! Adjust your temp is as just as easy. Find your perfect flow with the easy to use temperature dials.Setting up this propane water heater simply takes 10 minutes

More Showers with Less Water: Once you have your ideal temperature you can simply control your shower by switching the shower rose on / off. Giving you time to soap up while saving water.Turn on your shower head again and take off where you left

【INSTANT & SUFFICIENT HOT WATER】 With real powerful 14kW smart heating system, the tankless hot water heater electric ECO140B supplies sufficient instant and endless hot water of 120℉ or higher in seconds, no waiting for preheating nor terrible temp fluctuation during shower time any more and no worry of running out of it. Perfect companion for small apartment use, including shower, sink faucets, dishwasher, washing machine, etc.

【SELF MODULATION INSTANT WATER HEATER】The electric on demand tankless hot water heater ECO140B adjusts exact power input based on current flow rate and temp setting. For example, less power will be consumed by the smart water heater when you reduce water flow, thus, you get ideal temperature instead of scalding hot, which ensures comfortable experience and excellent energy efficiency. Also, optimal energy efficiency of 98% saves considerable electric charge for you.

【CONVENIENT USE】The electric tankless water heater 14kW comes with digital display & touch control panel so temp setting is easy job. Best of all, useful information on the screen helps you get full understanding of the working status of the 240V water heater tankless, you needn’t go through hard lesson of setting. Now turn on the faucet and let the smart instant hot water heater do the rest.

[No Wait for Hot Water] - Point of use 1.3 gallons mini tank water heater provides instant hot water where you need it with fast recovery, reducing standby loss. Thermal efficiency up to 99%

[Small Compact for Sink] - The hot water heater is compact designed for your sink with dimensions 11.42" x 11.42" x 9.65", can be wall or floor mounted under sink / counter, plug into a standard 120V outlet. Nominal current 12amps

[Adjustable Temperature] - Thermostat with 3 temperature level settings, range from 77°F to 140°F with high temperature limit protection, also a freeze mode to prevent tank from freezing

𝐂𝐨𝐦𝐩𝐚𝐜𝐭, 𝐋𝐢𝐠𝐡𝐭 𝐖𝐞𝐢𝐠𝐡𝐭 𝐏𝐨𝐫𝐭𝐚𝐛𝐥𝐞 𝐃𝐞𝐬𝐢𝐠𝐧 - 12.8 (L)*6.1(W)*21.65(H) inches, weight-18 lbs. Compact and portable design perfect for barns, cabins, outdoor instant hot shower and road trips

𝐄𝐚𝐬𝐲 𝐈𝐧𝐬𝐭𝐚𝐥𝐥𝐚𝐭𝐢𝐨𝐧 & 𝐔𝐬𝐞 - Simply connect the inlet and outlet pipes and gas regulator that come with this portable water heater, insert 2 D-cell batteries, then you are ready to use. Low water pressure start of 3.6 PSI allows you to enjoy 2.64 gallons of water in just a few minutes

𝐏𝐨𝐰𝐞𝐫 𝐄𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐭 & 𝐄𝐧𝐞𝐫𝐠𝐲 𝐒𝐚𝐯𝐢𝐧𝐠 - Maximum power output 68,000btu/hour with 11.5% energy saving technology, you will get instant endless hot water easily wherever you are. The propane water heater exchanger and main burner are designed with advanced combustion technology to decrease gas consumption and burning noise

🐠【50W Compact Fish Heater】110-120V/60HZ square shape design small aquarium heater, fast heating for small fish tank. 50W tank heater is for 3-10gallon, 100W tank heater is for 10-20 gallon. The power cord is 5ft, long enough for use indoors. With 2 strong suction cups at the back side of the betta heater, it's easy to install it on to glass, acrylic or plastic tank

🐠【Shut off When Out of Water】BOEESPAT aquarium heater adopt newest technology, it is a fully submersible aquarium heater for fresh water and saltwater tank, when the top part of betta fish heater is out of water it will be forcibly stopped. After putting it in the water again, the fault disappears and normal operation resumes.It is a safe and reliable water heater tank

🐠【Small Aquarium Heater with External Controller】You can set the temperature outside the fish tank through the external controller, and the fish tank accessories of temperature sensing built in will cyclic heating the tank water automatically .Temp range from 65℉ to 93℉. Every time you set your betta fish heater, just press the button over and over until it reaches to your desired temp, then stop and wait the digit flashing for 3 times, then setting is done

【INSTANT & SUFFICIENT HOT WATER】Applied with 5.5KW heating system, the on demand electric water heater supplies instant, consistent and endless hot water of 116℉or higher temp shortly, no waiting for preheat nor terrible temp up & down, perfect companion for sinks. Time to get rid of those "lukewarm" toys.

【SMART SELF ADJUSTMENT】The electric hot water heater ECO55 adjusts power input based on flow rate and temp setting in real time. For example, less power will be applied by the system of smart instant hot water heater when waterflow reduced, thus you still get ideal temperature instead of scalding hot water, which means comfortable experience. Optimal energy efficiency of 98% saves considerable electric charge.

【CONVENIENT USE】The tankless water heater electric comes with digital display & touch control panel so temp setting is easy job, you needn’t go through hard lesson of getting full understanding of working status of the 240v water heater tankless. Now turn on the tap and let the smart unit do the rest, just enjoy the instant hot water.

Endless Hot Water: Enjoy unlimited hot water flow throughout the house; compact, durable, and easy to install; professional installation recommended

Energy and Space Efficient: Space-saving design conserves energy as it heats only when necessary

Optimal Water Pressure: Up to 7 GPM hot water flow rate for a powerful, constant stream

Easy To Install -It only takes you 5 minutes to set up and it comes with all necessary accesories.To avoid gas leakage caused by improper sealing of the water heater, DO NOT TWINE TEFLON TAPE between gas regulator and gas inlet pipe. The tankless water heater will "caught on fire "with improper operation. Always check gas leakage before operation.

4.22 Instant Hot Water-It only takes you a few minutes to get 4.22 gallons per minute of instant hot water. The camplux portable water heater lights when water pressure between 4.0-110 PSI, low water pressure is perfect for campings and remote cabins.

6-in-1 Protection Ensure Your Safety-Flame failure device, anti-freezing protection, over heating protection to ensure the family safety. The anti-freezing drain plug discharges the residual water to avoid freezing in cold areas for long-time maintenance. Gas supply automatically shut off when high water temperature protection over 167 °F.

Original Design: Tankless hot water heater only heats when necessary to conserve energy; For the latest in non-condensing technology and a cleaner layout that speeds up service and installation, check out our new RE199iN model

Never Run Out of Hot Water with this Compact Tankless Gas Water Heater: Non-condensing tankless hot water heater from Rinnai is only the size of a small suitcase and fits in a wide variety of spaces, but provides up to 9.8 GPM (6 fixtures at once)

Smart, Durable Design: Enhanced scale detection helps prevent serious, long-term damage to unit; Includes 15-, 5-, and 1-year residential guarantee for heat exchanger, labor, and parts, respectively; See Controlr module for WiFi control (not included)

[Fully Submersible Aquarium Heater] This 100W 110V Strong Quartz Glass Aquarium Fish Tank Heater is suitable for aquariums from 10-30 gallons; includes 150-200cm (5-6.5 feet) cable for easy use. The heater should be submersible fully under the water before turn on

[Explosion-proof Shatterproof Shield-proof Design] Thanks to its high quality Quartz Glass material and its Protective Sleeve, aquarium heater is shatter resistant & more durable than conventional glass heaters

[Provides Accurate Thermal Control] Set and adjust the desired temperature with the use of the Temperature Controller on the top. This allows accurate thermal control via the easy set thermostat for precise