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.
Bierwächter schrieb:
Registered for 2 people, you also don't exceed the limit values.Are there also 2 meter numbers for that?
Hi,
For pure self-consumption, this is simply way too much. Splitting could be interesting—operate the south side as a full feed-in system while the north side still provides more than enough. But haven’t the feed-in conditions significantly worsened? If the original poster can get the system for a good price, then go for it. But I guess it needs to be below 1,000 €/kWp (about $1,100/kWp) to really be worthwhile.
Best regards,
Andreas
nordanney schrieb:
Why? You could even make two systems with different purposes: full feed-in versus self-consumption system. Especially at this size, the system becomes extremely cheap (calculated per kWp).
For pure self-consumption, this is simply way too much. Splitting could be interesting—operate the south side as a full feed-in system while the north side still provides more than enough. But haven’t the feed-in conditions significantly worsened? If the original poster can get the system for a good price, then go for it. But I guess it needs to be below 1,000 €/kWp (about $1,100/kWp) to really be worthwhile.
Best regards,
Andreas
N
nordanney2 Jun 2025 21:07andimann schrieb:
If the original poster gets the system for a good price, then go for it. But I guess it has to be below €1,000 per kWp to really be worth it.€500 including storage should be attractive enough.Ok, if that's the case:
Then that sounds like a lot of fun! But to do it for 20,000€ (about $22,000), you'll really have to shop very economically!
Good luck!
Andreas
Bierwächter schrieb:
I think I could get everything done for under 20,000€ (about $22,000). High-quality panels, mounting materials, storage, inverter, and the electrician for the inspection.
Then that sounds like a lot of fun! But to do it for 20,000€ (about $22,000), you'll really have to shop very economically!
Good luck!
Andreas
Hi,
Most of them should easily handle that. They are usually designed for it. It’s just better if they don’t get rained on directly.
Best regards,
Andreas
tomtom79 schrieb:
The wr brand sma from the neighbor has been hanging under the carport for 3 years. Back then I would have worried more about thieves, but in the tata there are some that are allowed to be outside.
Most of them should easily handle that. They are usually designed for it. It’s just better if they don’t get rained on directly.
Best regards,
Andreas
N
nordanney2 Jun 2025 22:06andimann schrieb:
But for €20,000 (around $22,000), you really need to shop very cheaply! Well, the 450-watt modules (that’s 36 pieces) start at about €1,800 (around $2,000). Inverters aren’t expensive either. Two units together roughly cost €3,500 (around $3,900) (one hybrid, one standard). Then you add a 20–30 kWh (around 22–33 kWh) battery starting at €5,000 (about $5,600). Some mounting, wiring, etc., and the budget fits comfortably.
DIY and no installer’s warranty.