A cold shower on a January morning is not an invigorating ritual, it is a signal: something is wrong with the water heater. Or it is simply not enough for a family of four.

The problem is deeper than it seems. The market offers dozens of solutions: storage, tankless, indirect heating, heat pumps, solar collectors. Each has its own efficiency, heating speed, and installation cost. A mistake at the selection stage results in years of overpaying.

Below, which types of water heaters actually work in a private home, how they differ by the numbers, and what to install given your inputs.

💡 Quick overview:

• We break down five main types of water heaters: from storage to heat pumps and solar systems.
• We compare them by key parameters: heating speed, energy efficiency, 10-year cost of ownership.
• We provide a selection matrix: "if you have gas, get X; if you only have electricity, take a closer look at Y."

Types of water heaters: operating principle and key differences

To choose a domestic hot water (DHW) system consciously, you need to understand the physics behind each type. Here are the five main options.

Electric storage: cheap upfront, expensive to run

The most common option in the CIS. A tank with a volume of 30 to 200 liters, with a heating element inside that heats water to a set temperature and maintains it. It is inexpensive, and installation is simple: you need an outlet and a cold water supply line.

But there is a nuance. Heating 100 liters from 10 to 60 °C takes about 5.8 kWh. At a tariff of 4.32 UAH/kWh (Ukraine, 2026), that is about 25 UAH per cycle. Multiply by 30 days, and you get 750 UAH per month just for heating. Plus tank heat loss: even with good insulation, 1.5-2 kWh per day is wasted.

Who it suits: an apartment or a vacation home with 1-2 users, where there is no gas.

Gas storage: cheaper to run, more complex to install

The same tank idea, but heated by a gas burner instead of an electric element. The key advantage is the cost of energy. A cubic meter of gas costs about 7.96 UAH; heating 100 liters takes roughly 0.6 m³, around 5 UAH per cycle. The difference with electricity: a factor of 5.

Downsides: you need a chimney or a coaxial wall outlet, a project design, and approval from the gas service. Installation costs several times more than the electric equivalent. But if gas is already connected to the house, this is the most economical option for a family of 3-5 people.

Tankless: compactness at the cost of power

Heats water only when you open the tap. There is no tank; water passes through a heat exchanger and is heated instantly. It takes up minimal space.

But the power requirements are strict. An electric tankless model for a shower, 12-18 kW, needs a dedicated power line from the panel. A gas tankless unit, 24-28 kW, is comparable to a heating boiler. With old wiring or weak gas pressure, a tankless unit will not start.

Plus: hot water never runs out. Minus: with two draw-off points open simultaneously, the temperature jumps without flame modulation.

Heat pump water heater: 300-400% efficiency

A technology that extracts heat from the air in the room and transfers it to the water in the tank. For 1 kWh of electricity consumed, it delivers 3-4 kWh of heat; this is not magic, but the Carnot cycle.

According to ENERGY STAR, a family of four saves about $550 per year with such a water heater compared to a standard electric one. The unit itself costs from $1,500 to $3,000, 4-6 times more than a storage heater. With a service life of 10-15 years, the difference pays for itself.

Limitation: a heat pump needs a room volume of at least 28 m³ and an air temperature no lower than 5 °C. It will not work in an unheated basement or on a balcony.

Solar collector: almost free water in summer

Vacuum tubes or flat panels on the roof collect solar heat and transfer it to water in a storage tank. In summer, they cover up to 90% of hot water demand; in the off-season, 40-60%. According to Solar Heat Europe, by the end of 2023, the global installed capacity of solar water heaters reached 560 GW thermal, equivalent to 800 million m² of collector area.

In Ukraine and CIS countries, a solar collector works in tandem with a backup source (an electric heating element in the tank or a gas boiler): in winter and on cloudy days, there is not enough sun. Initial investments range from budget to premium; payback is 5-8 years. The carbon footprint approaches zero.

Comparison table: five types of water heaters by the numbers

*Calculation for a family of 3, Ukraine, 2025-2026 tariffs. Excluding maintenance.

Smart technologies in DHW: what actually works

A modern water heater is not just a tank with a heating element. Over the past 5 years, three technologies that genuinely save money have entered the mass segment.

Wi-Fi control and scheduling. Via an app (Atlantic Cozytouch, Ariston Net, Thermex), you set a heating schedule. The tank heats water only at night on the cheap tariff or an hour before waking up. You turn off heating during a vacation; the monthly saving is comparable to half a monthly bill.

Adaptive algorithms. The water heater memorizes consumption patterns over 7-14 days and decides for itself when and to what temperature to heat. According to manufacturer Ariston, self-learning algorithms yield up to 30% savings; consumer tests by Which? (2024) record 15-20%.

Integration with solar panels. Excess daytime generation is directed not to the grid under a "feed-in tariff," but to water heating. A controller (e.g., My-PV AC-THOR) monitors the balance and supplies power to the heating element when the house is exporting energy to the grid. With a 5 kW home solar power system, hot water costs zero from April to September.

Installation and maintenance: where you should not cut corners

Water heater installation is not an expense item on which you should save. Incorrect installation of gas equipment is deadly, and a mistake with an electric storage unit risks a leak of 150 liters of boiling water.

Gas models: installation only by a certified gas service specialist. A chimney or coaxial pipe, a dedicated gas supply valve, and automatic shut-off if the flame goes out. The average installation cost is 3,000-6,000 UAH.

Electric models: you can install them yourself if you have a grounded outlet and an RCD, but it is better to call an electrician. A pressure relief valve with a drain to the sewer is mandatory: if it boils over, it will release pressure and prevent the tank from rupturing.

Maintenance: once a year, replace the magnesium anode (protects the tank from corrosion); once every 2-3 years, clean the heating element of scale. Without this, the tank rots out in 5-6 years instead of the rated 10-12.

Specific models and installation tailored to your inputs are selected at https://bt-service.ua/uk/garjachee-vodosnabzhenie.

The difference between water heater types is clearly shown in a video by practicing installers, with real installation examples and energy consumption figures.

⁉️🤔 Frequent questions

Which water heater is more cost-effective, gas or electric?

At current tariffs for gas (7.96 UAH/m³) and electricity (4.32 UAH/kWh), a gas storage unit costs about 5 times less to run than an electric one. But if gas is not connected to the house, running a line can cost 50,000-150,000 UAH; with those inputs, a heat pump or an electric storage unit is more sensible.

Is an 80-liter boiler enough for a family of three?

At a temperature of 60 °C and diluted to 40 °C, you get about 120 liters of washing water. One person uses 30-50 liters for a shower, and dishes take 10-15. For three people, 80 liters is tight: two have showered, the third waits 1.5-2 hours for reheating. The minimum comfortable volume for a family of three is 100 liters, and 120-150 is better.

How long does a magnesium anode last, and what happens if you don't replace it?

The anode's service life is 1-2 years depending on water hardness. Without an anode, corrosion attacks the tank walls: first micro-fistulas, then a leak. Replacing the anode costs 200-500 UAH and 20 minutes of work; replacing the tank costs the price of a new water heater.

Can you install a heat pump in an apartment?

Technically yes, but with limitations. You need a room volume of at least 28 m³ (a 12 m² kitchen with a 2.5 m ceiling works) and ventilation. An outdoor heat pump for DHW is an option for a private home. The compressor noise of 45-55 dB is comparable to a refrigerator.

Is it mandatory to install DHW recirculation in a private home?

If the distance from the water heater to the tap is more than 10 meters, yes. Without recirculation, you drain 5-10 liters of cold water every morning while waiting for hot. A circulation pump with a timer consumes 25-60 W and pays for itself through water savings in 1-2 years.

Which water heater pays off faster: the final breakdown

If you live in a house with mains gas, get a gas storage unit or a combi boiler. The cheapest option to run; it recoups the difference with an electric unit within the first year.

If there is no gas, a heat pump. Yes, it is several times more expensive upfront. But over 10 years, the difference in bills covers the overpayment twice; with a home solar power system, the payback period drops to 3-4 years.

If the budget is minimal, get an electric storage unit with a volume suited to the number of people and definitely with a Wi-Fi module. Scheduling for the night tariff and turning it off during vacation yield savings without increasing the upfront price.

For a seasonally used vacation home, an electric storage unit of 50-80 liters. Drain the water for winter, turn it on in spring.

Tell us in the comments which type you installed and how much you pay per month. Also, check out the breakdown on choosing a heating boiler; in a private home, DHW and heating are often solved together.