ELWA in double pack in Denmark

Reference project Denmark

2 ELWAs completely replace gas the heating system for 8 months – for hot water and for heating.



Client/owner/planner: Thomas Storgaard

Location: Skive, Denmark
Construction type: Single-family house, well insulated, 230 m².
Low-energy house with some modern insulation techniques 
Construction year: Newly built in 2009
PV-power and orientation:

12 PV-modules with 425 W each, facing south, 30 degrees inclined

Heat storage size: New 750 l buffer storage with hot water circulation
my-PV product in use: 2 ELWAs are operated independently, 6 PV modules are assigned to each ELWA
System control by/with:

Not necessary, monitoring is carried out via the Modbus interface using the ELWA communication protocols/APIs as part of the Smart Home integration.


Customer declaration

How did you come to my-PV?

I found the Austrian manufacturer of photovoltaic heating solutions via Google. A lot of DIY applications can be found on the internet, which often have the flaw that the systems do not work together or can only be used together partially or even interfere with each other. This is not the case with the my-PV system, as it continuously adjusts the variable power and regulates it accordingly. This is not an on/off logic, but much higher than that – and this system has convinced me.


Obstacles/specialities during the installation

Installation is really simple. The piping of the new tank was a big task compared to the commissioning of the ELWA.


Brief explanation of the system – what should be mentioned?

Until now, the heating was provided by natural gas. Since the installation of the photovoltaic system together with the two ELWAs from my-PV, the natural gas has been turned off, because the PV power is sufficient to cover the demand from March to September.

The homeowner has installed an intelligent valve system that enables efficient use of hot water. In summer, the gas is turned off completely and there is no water supply through the gas stove for hot water heating - this is possible solely with ELWA, even in Denmark! The target temperature on ELWA is set at 60 °C, and the hot water is used primarily for sanitary purposes, in the kitchen and then for space heating, as the owner has water-based space heating. If the temperature of the hot water (space heating) is above 35 °C, it mixes with cold water and is then used for space heating to keep the system safe.


Persons in the household – hot water demand etc.?

5 people live in the 230 m² single-family house, 3 of them are adults. On average, 12 kW per day are used for hot water.


Is hot water backup with mains power used?

In this case, no hot water backup via mains electricity is activated, as only electricity from the sun is sufficient.


Any cost changes/ROI?

The system runs from March to October. The investment required for this is roughly equivalent to the gas bill for one year. The expected gas price for 2022 is €4,500, normally €1,600 has been paid so far, but in 2022 the price will more than double. It is estimated that there will be an amortization of the investment in 4-5 years. The EU is also pushing to reduce gas consumption in Denmark by 2030.


Personal customer opinion and resume:

ELWA from my-PV is easy to operate, you don’t have to think about anything. It is very effective, even on cloudy days, every day, the desired temperature of the hot water was reached.


my-PV GmbH
Betriebsstraße 12
A-4523 Neuzeug

+43 7259 39328

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About us


We at my-PV get more out of photovoltaics than just electricity, we move your building technology into the future. Use your solar power yourself instead of feeding it into the public grid: Electricity, hot water, heating and charging options for your e-car. With our products, you can use your self-generated photovoltaic electricity for your own needs without any detours. This way, you save costs in the long term and act environmentally friendly!



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