Hi,
my photovoltaic system planning is likely going to end up at around 38 kWp (kilowatt-peak). The pitched roof will be fully covered on the south and north sides.
My main concern is that I was told (in the relevant forum) that the inverters get quite warm and that I shouldn’t install them in the utility room. We don’t have a basement, and our utility room is about 8.3 m² (90 sq ft). It will be a KfW 40 energy-efficient house. The garage is on the opposite side of the property and is planned to be built later, not directly connected to the house. A carport is planned directly adjacent to the utility room. Currently, I would probably try to install the inverters there. We will have two inverters because of the system size and string configuration. However, our house manufacturer uses a very light plaster, and the inverters are too heavy to mount directly on it. So I would need to mention this during the final selections and have wooden beams installed under the plaster, which would be expensive. Alternatively, I could somehow mount them on the carport itself, but I don’t want to significantly reduce the driveway width since it’s already quite narrow. I could also take the risk and install the inverters in the utility room after all. However, I have heard of cases where temperatures of 40°C (104°F) were reached there. Some people use fans to get rid of the heat. In our KfW 40 house, that probably wouldn’t even be allowed.
I can hardly find any information about this online. Some people report no problems even with 2 m² (22 sq ft) utility rooms; others have temperatures around 30°C (86°F). There is never information about the type of houses, and some posts are up to 10 years old. We are building a 103 m² (1,109 sq ft) bungalow for two people, with an Alpha Innotec Hybrox 5 (70 m² to 150 m²) air-to-water heat pump and a decentralized ventilation system.
Has anyone here had experience with inverter heat? How would you approach this issue? The battery storage obviously has to go in the utility room; it can’t be installed elsewhere.
my photovoltaic system planning is likely going to end up at around 38 kWp (kilowatt-peak). The pitched roof will be fully covered on the south and north sides.
My main concern is that I was told (in the relevant forum) that the inverters get quite warm and that I shouldn’t install them in the utility room. We don’t have a basement, and our utility room is about 8.3 m² (90 sq ft). It will be a KfW 40 energy-efficient house. The garage is on the opposite side of the property and is planned to be built later, not directly connected to the house. A carport is planned directly adjacent to the utility room. Currently, I would probably try to install the inverters there. We will have two inverters because of the system size and string configuration. However, our house manufacturer uses a very light plaster, and the inverters are too heavy to mount directly on it. So I would need to mention this during the final selections and have wooden beams installed under the plaster, which would be expensive. Alternatively, I could somehow mount them on the carport itself, but I don’t want to significantly reduce the driveway width since it’s already quite narrow. I could also take the risk and install the inverters in the utility room after all. However, I have heard of cases where temperatures of 40°C (104°F) were reached there. Some people use fans to get rid of the heat. In our KfW 40 house, that probably wouldn’t even be allowed.
I can hardly find any information about this online. Some people report no problems even with 2 m² (22 sq ft) utility rooms; others have temperatures around 30°C (86°F). There is never information about the type of houses, and some posts are up to 10 years old. We are building a 103 m² (1,109 sq ft) bungalow for two people, with an Alpha Innotec Hybrox 5 (70 m² to 150 m²) air-to-water heat pump and a decentralized ventilation system.
Has anyone here had experience with inverter heat? How would you approach this issue? The battery storage obviously has to go in the utility room; it can’t be installed elsewhere.
O
Oberhäslich2 Jun 2025 22:10From 30 kWh onwards, you have to pay income tax, meaning income tax declaration and so on.
N
nordanney2 Jun 2025 22:27Oberhäslich schrieb:
From 30kWh you have to pay income tax, meaning income tax declaration, etc.That’s why there are two systems. Everything can be optimized (although I see the tax as a minor issue since, at the initial cost, such a system is a no-brainer. It either performs exceptionally well or at least very well).
This year, we have newly installed a photovoltaic system and received a 10kW inverter.
When the sun is shining and the inverter is working hard, the utility room becomes noticeably warmer. Since we do not have a basement and the utility room was previously the coolest place, we used to store potatoes and onions there, but that no longer works.
When the sun is shining and the inverter is working hard, the utility room becomes noticeably warmer. Since we do not have a basement and the utility room was previously the coolest place, we used to store potatoes and onions there, but that no longer works.
Hello,
as mentioned before, inverters always have power losses that are converted into heat. Depending on the quality and power range, this is typically between 1-5%. Realistically, expect around 2-3% of the output to be generated as heat. For large systems, this can quickly amount to 1 kW or more.
Best regards,
Andreas
as mentioned before, inverters always have power losses that are converted into heat. Depending on the quality and power range, this is typically between 1-5%. Realistically, expect around 2-3% of the output to be generated as heat. For large systems, this can quickly amount to 1 kW or more.
Best regards,
Andreas
B
Bierwächter3 Jun 2025 17:54The compensation has unfortunately become significantly worse, yes. Still, from what I’ve heard, it’s recommended to fully equip the roof. If I weren’t installing it myself, I might reconsider or at least run the numbers very carefully again.
The Sungrow inverters I currently have in mind are specified with a 2% power loss. I think around 800W could be generated by that.
For the battery, I initially thought of maybe 5–7 kWh. After a year, I would check our consumption and expand if necessary.
For the roughly €20,000 (about $22,000), I even calculated with the expensive Aiko panels. At 80 panels around €8,000 (about $8,800) roughly. But each with 475 Wp and great aesthetics.
The Sungrow inverters I currently have in mind are specified with a 2% power loss. I think around 800W could be generated by that.
filosof schrieb:Could you share a bit more about that? Room size? Ventilation system? KfW40 (energy-efficient building standard)? Domestic hot water heat pump installed? Those extract heat from the room.
From my own experience: I have just under 28 kWp on the roof and a 25 kW inverter from Solaredge in the utility room. I can’t say it gets excessively hot there. At the same time, of course, I don’t know how it would be with two of those devices...
For the battery, I initially thought of maybe 5–7 kWh. After a year, I would check our consumption and expand if necessary.
For the roughly €20,000 (about $22,000), I even calculated with the expensive Aiko panels. At 80 panels around €8,000 (about $8,800) roughly. But each with 475 Wp and great aesthetics.
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