Roof covering and solar technician selection - Decision?

Hello everyone,

I am about to decide whether to hire a solar installer. I am building a turnkey single-family house with a pitched roof, 25° roof pitch, oriented north/south, in 84xxx with a general contractor (GU). There are no skylights, chimneys, etc. on the roof, so conditions are optimal.

I am having some difficulty in obtaining quotes at all and now have at least 2 offers. I would appreciate it if someone could help me evaluate and choose (both which company and north yes/no). I have not requested a storage system; I might retrofit one later if it becomes cheaper.

So, first of all, I am facing the question of north yes/no. I can fit about 25 modules on each side, so about 10 kWp each. PVGIS outputs around 10,000 kWh for south and about 7,000 kWh for north.

Offer 1 is from a solar installer with many years of experience, who not only does single-family houses but also installs large systems in the multi-megawatt range. My general contractor, who is building the house turnkey for me, also has many years of experience with this installer and recommends him.

Offer 1 looks like this:
- 20.5 kWp
- 50 x Q-Cells Q-Peak ML G10 410 heat pump
- 50 x SolarEdge power optimizers, S440 WorldWide (v1)
- SolarEdge StorEdge three-phase inverters: SE10K-RWS-EU-APAC/AUS (v1) and SE7K-RWS-EU-APAC (v1)
- SolarEdge Smart Meter for self-consumption display
- All other materials, installation and commissioning services are included
- Cost: €31,980 net, thus €1,560 net --> seems relatively okay nowadays, not really cheap, but not super expensive either

And now to Offer 2. The offer is from a very small and new electrical company that I was able to inquire about through a neighbor’s recommendation. The company does not even have a finished website because it is very new, but it has already done electrical work in the construction area (I do not know about photovoltaics). However, two different neighbors have already told me that the company is supposed to be good.

Offer 2 looks like this:
- 20.9 kWp
- 51 x JinkoSolar solar module Tiger NE HC N-Type sw JKM410N-54HL4-B
- 2 x SMA inverters STP10.0-3SE-40
- 1 x SMA Sunny Home Manager HM-20
- I will leave out the other materials, but mounting, planning and commissioning services are also included here
- Cost: €25,570 net, thus €1,223

Now my questions:
- What do you generally think about the materials used?
- The SolarEdge power optimizers in Offer 1 are not really necessary, right? Given the location, I am expecting absolutely no shading from trees, chimneys, or anything else
- Company 2 is probably somewhat risky, but the price is really very attractive. Is it worth taking the risk here?
- Is the north installation worthwhile at all in the case of Offer 1? If I calculate north and south, south is obviously worthwhile in both cases anyway. North is (according to my calculation) only worthwhile with Offer 2... with Offer 1 I would be making a loss.

I would be very grateful for a brief assessment!

Best regards

- What do you generally think about the materials used?

Both do what they are supposed to.

- The SolarEdge power optimizers in offer 1 aren’t really necessary, right?

No, you can skip them.

- Company 2 is probably somewhat risky, but the price is really more than hot. Is it worth taking the risk here?

What risk? Every photovoltaic system I have installed so far was only paid after delivery of materials, installation, and final commissioning. Not a single € paid in advance.

- Is the north orientation worth it at all in the case of offer 1? When I calculate north and south, south is of course worthwhile in both cases anyway. North is only worthwhile (according to my calculation) in offer 2... with offer 1 I would make a loss.

Financing or equity? How is the self-consumption (e-car)?
I would take both sides. Only south certainly costs €15k net, so north additionally only €10k.

Both do what they are supposed to.

No, you can save yourself that.

What risk? Every photovoltaic system I have installed so far was only paid after material delivery, installation, and final commissioning. Not a single € in advance.

Financing or equity? What is the self-consumption (e-car)?
I would take both sides. Only south certainly costs €15k net, so north additionally only €10k.

Thank you very much for your helpful answer! True, you are right about the risk. Self-consumption is about 10,000 kWh (including air-to-water heat pump), no e-car yet (but that could come at some point).

Regarding SolarEdge: the solar installer probably included it because it is little effort for him and a good profit, right? According to Google, they cost between €60-100. So the whole thing should make up something in the range of €3,000 - 5,000 on the offer.

Would tend towards offer 2 (but definitely "roof full") since SE is totally unnecessary. In addition, the SMA components are supposed to be quite good. I only wonder with offer No 2 why 2 inverters? But it could be that what is deliverable at the moment has to be taken. PVGIS is conservative, usually a bit more comes from the roof than shown there. What do both say about delivery times?

Self-consumption is about 10,000 kWh (including air-water heat pump), no electric car yet (but could come at some point).

I doubt that. How do you want to arrive at this self-consumption? I have a 10 kW PV system including electric car (hybrid and home office, thus partly charging 10 kWh 2-3 times daily) as well as an air-water heat pump and would be happy with such a self-consumption rate.

I doubt that. How do you come to this self-consumption? I have a 10 kW PV system including an electric car (hybrid and home office, so partly charging 2-3 times daily with 10 kWh) as well as an air-to-water heat pump and would be happy with such a self-consumption rate.

Oh damn, sorry. I actually meant the total annual consumption of our household. So 10,000 in total. I estimate the self-consumption at about 2,000 kWh