Home / fothermo News / 2,000 watt balcony power plant for hot water and electricity production
2.000 Watt Balkonkraftwerk für die Warmwasser- und Stromproduktion

2,000 watt balcony power plant for hot water and electricity production

Use the photovoltaic electricity generated in the balcony power plant to reduce not only your electricity costs but also your hot water costs.

Save up to €450 on electricity costs per year.

Maximize the benefits of your balcony power plant

The most important rule for balcony power plants or plug-in solar systems is: maximize your own consumption. Only the electricity you use saves you money.

The problem – low self-consumption:
A commercially available balcony power plant with 2 photovoltaic modules produces around 800 kWh of electricity per year when well aligned to the south. The problem: You can only use the electricity that you use directly in your household. Excess electricity is fed into the public power grid without compensation.

For this reason, it is desirable to operate electrical consumers as evenly as possible throughout the day. However, this is often not possible because, for example, no one is home during the day or the electrical devices draw an uneven amount of power.

Increase the share of your balcony power plant’s own consumption

The solution:
You must increase your own consumption share of the photovoltaic electricity generated. This means you can use more photovoltaic electricity and therefore have to draw less energy from the power grid. You can essentially increase your own consumption in two ways:

1. Switch on electrical devices, especially during the day.
2. Store energy.

If you are not at home during the day, the first option is usually not feasible. Then there’s energy storage. This in turn offers two options:

1. Energy storage in the battery.
2. Energy storage in hot water.

The problem with storing energy in batteries is that they are very expensive to purchase. A 1 kWh battery that can last up to 3,000 full cycles (completely charged and discharged 3,000 times) can save a maximum of €1,000 at an electricity price of €0.33/kWh. (3,000 kWh x 0.33 €/kWh = 1,000 €). So if the battery costs €1,000 to purchase, it would have needed a maximum of €1,000 in savings at the end of its life. The battery for the balcony power plant is therefore NOT economical.

Solution: Energy storage in hot water:

However, things look much better when it comes to energy storage in the form of hot water. Providing hot water is very energy intensive. Heating an 80 liter boiler from 15 °C to 65 °C requires 4.6 kWh.

An average household requires around 4 kWh per day to heat water. At €0.33/kWh electricity costs, that's around €1.33 per day or €480 per year. Only for hot water provision!

If you shower in the evening or the next morning anyway, then it makes sense to store all the photovoltaically generated energy in hot water. This enables you to use, or better yet store, large amounts of energy during the day.

Advantages of photovoltaic boilers and heating elements from fothermo

So that you can generate as much hot water as possible using photovoltaic energy, you need a photovoltaic heating element or a photovoltaic boiler. This can continuously regulate its heating output.

For example, if the photovoltaic modules generate 375 watts, the photovoltaic boiler will limit its heating output to 375 watts. As soon as the performance of the photovoltaic modules changes, the performance of the boiler also adapts. A classic electric boiler, for example, can only be operated “on” or “off” or with 0 watts or 3,000 watts of heating power.

Conclusion after one year 2,000 watt balcony power plant

Great feeling - CO2 free hot water

Showering becomes more enjoyable when you know that all the energy has been provided for free by the sun.

Hot water costs reduced by €300 and electricity costs by €125

You also become less dependent on rising electricity prices. You produce your own hot water.

3 - 4 year payback period

After a few years, your investment will have been paid off and you can produce your own free hot water.

When the boiler/heating element is fully heated, excess energy is fed into the power grid.

Especially in the summer months, the photovoltaic boiler is fully heated up by mid-morning.

So what happens to the excess photovoltaic energy? This can be fed into a standard 600 W / 800 W micro PV inverter via the fothermo switching device.

This enables you to significantly reduce both your hot water and your electricity costs. So you save twice.

Advantages of the 2,000 watt balcony power plant

The main advantage is that the entire system counts as a simple balcony power plant. You do not need to make any changes in the meter cabinet. You can put the entire system together without an electrician, as it only works in safety extra-low voltage.

You pay around 80% less than for a standard photovoltaic roof system. At the same time, you can use almost as much energy in your own home. The only difference is that you feed less excess energy into the public grid.

And because you use the direct current directly, the entire system is much more efficient and does not require any programming knowledge or complex communication protocols. The entire system is simply plugged together. Complete.

Short payback period of around 4 years

The aim is for the boiler to absorb the photovoltaic energy generated throughout the day.

In this way, your own consumption and thus also your economic efficiency can be maximized.

The initial investment is usually paid back after 4 years. From now on you can enjoy your own free hot water and have also become even less dependent on rising energy prices.

80 liter photovoltaic hybrid boiler

  • 2,050 W heating output

    550 W photovoltaic and 1,500 W as intelligent post-heating via 230 V mains power.

  • easy installation

    No electrician is necessary for installation as the entire system works in safety extra-low voltage.

  • Registration free - island complex

    Since no electricity is fed into the grid, the photovoltaic system does not need to be registered.

  • 200 liters of 34 degree shower water

    At a maximum boiler temperature of 65 °C, you can mix around 200 liters of 34 degree shower water.

Don't lose any more power! - Surplus feed into the house network.

When the photovoltaic boiler is fully heated, excess energy can be fed into your own home network. A classic micro PV inverter or a balcony power inverter is used for this.

The inverter is simply plugged into the socket.

In addition to your hot water costs, you also reduce your electricity costs. And since the entire system is “just” a balcony power plant, registration is very easy.

More information about excess feed-in via the fothermo switching device: