Large 24kw residential system, need advice

[mab45]

Hello! My wife and I live in Pittsburgh and we're entertaining bids for our rather large solar project. We designed our large south-facing roof with solar panels in mind.

We've had 2 proposals put in front of us by highly recommended installers. We're on the fence and considering all options still. We currently use <gulp> about 31kw of electric annually. We are in the process of looking into ways to decrease this as well.

Proposal 1 is using SolarWorld 280W all-black panels, 3 inverters, total size 18,400 kW. Cost per watt is about $3.48. Estimated output 19,700 kW/year.

Proposal 2 is using LG 300W (all black) with SolarEdge inverters, 21,300 kW. Cost per watt is $3.19. Estimated output 24,335 kW/year.

These prices are BEFORE tax incentives. Again, both companies are experienced and highly recommended. Both also feel strongly about their preference of LG versus SW panels... Both proposals final cost is nearly identical, at about $66,000, but as you see the LG proposal is estimating significantly higher output.

Comments?? Advice? Much thanks in advance!

[donald]

How many years payback?

[mab45]

How many years payback?

8.5-9.5 years full paybackafter incentives/etc. This does not include immediate equity to the house.

[max2k]

Hello! My wife and I live in Pittsburgh and we're entertaining bids for our rather large solar project. We designed our large south-facing roof with solar panels in mind.

We've had 2 proposals put in front of us by highly recommended installers. We're on the fence and considering all options still. We currently use <gulp> about 31kw of electric annually. We are in the process of looking into ways to decrease this as well.

Proposal 1 is using SolarWorld 280W all-black panels, 3 inverters, total size 18,400 kW. Cost per watt is about $3.48. Estimated output 19,700 kW/year.

Proposal 2 is using LG 300W (all black) with SolarEdge inverters, 21,300 kW. Cost per watt is $3.19. Estimated output 24,335 kW/year.

These prices are BEFORE tax incentives. Again, both companies are experienced and highly recommended. Both also feel strongly about their preference of LG versus SW panels... Both proposals final cost is nearly identical, at about $66,000, but as you see the LG proposal is estimating significantly higher output.

Comments?? Advice? Much thanks in advance!

Common wisdom on this board is to start with your power consumption analysis. I hope, you've done that already. IMO, the second system looks overrated, I'd expect it to be much closer to the first one in real life.

[Cosmacelf]

It would be helpful if you got your figures and units correct. Do you mean your house uses 31,000 kWh per year?

[max2k]

It would be helpful if you got your figures and units correct. Do you mean your house uses 31,000 kWh per year?

and the power output for both systems are in Watts, not kW otherwise they'd produce annual output within 1 hr on a sunny day but who is counting ?

[gvl]

Both LG and SW are decent. The LG proposal is a better deal I think. A more important question is how much annual generation do you actually need?

[dat]

[QUOTE=mab45;158733
Proposal 1 is using SolarWorld 280W all-black panels, 3 inverters, total size 18,400 kW. Cost per watt is about $3.48. Estimated output 19,700 kW/year.

Proposal 2 is using LG 300W (all black) with SolarEdge inverters, 21,300 kW. Cost per watt is $3.19. Estimated output 24,335 kW/year.

These prices are BEFORE tax incentives. Again, both companies are experienced and highly recommended. Both also feel strongly about their preference of LG versus SW panels... Both proposals final cost is nearly identical, at about $66,000, but as you see the LG proposal is estimating significantly higher output.

Comments?? Advice? Much thanks in advance![/QUOTE]

Proposal 1: 18400Kw X $3.48 = $64032
Proposal 2: 21300 X $3.19 = $67947

The different between proposal 1 & 2 is 2900Kw for $3915 = $1.35/Kw (2900Kw). I would take proposal 2.

[gregvet]

We currently use <gulp> about 31kw of electric annually. We are in the process of looking into ways to decrease this as well.

If I used 31 kWh annually, I would not be thinking about solar. My all electric residence consumes 21,000-24,000 kWh electricity with a net of 7,000-8,000 kWh annually. I suspect you meant 31,000 kWh annually?

[mab45]

If I used 31 kWh annually, I would not be thinking about solar. My all electric residence consumes 21,000-24,000 kWh electricity with a net of 7,000-8,000 kWh annually. I suspect you meant 31,000 kWh annually?

Yes, 31,000 kWh. Thanks

[mab45]

Proposal 1: 18400Kw X $3.48 = $64032
Proposal 2: 21300 X $3.19 = $67947

The different between proposal 1 & 2 is 2900Kw for $3915 = $1.35/Kw (2900Kw). I would take proposal 2.

Ok, thanks, this is what I was thinking too.

You don't value SW versus LG, or vice versa enough to offset this difference? Does anyone?

[Cosmacelf]

Good price, good technology, I would go with door #2. Btw, how is he proposing to connect it to the grid? Load side tap, or do you have a big electrical service/panel?

[mab45]

Good price, good technology, I would go with door #2. Btw, how is he proposing to connect it to the grid? Load side tap, or do you have a big electrical service/panel?

Thanks! And Load-side tap for this size

[donald]

If I used 31 kWh annually, I would not be thinking about solar. My all electric residence consumes 21,000-24,000 kWh electricity with a net of 7,000-8,000 kWh annually. I suspect you meant 31,000 kWh annually?

Big house with ground loop heat pump, it seems.

Anyways, this is a now or wait question. Within ten years those roof panels will be worth $4-5K and the inverters will be ready for replacement. So equity is not really part of the purchase decision.

Personally, I would try to negotiate the lower quote down to under $3/watt. Ask if the solaredge inverters will accept batteries in the future. Perhaps reduce the size of the larger, less expensive system. Paying a small amount each year is usually the sweet spot.

[quitepossibly]

Proposal 2 is using LG 300W (all black) with SolarEdge inverters, 21,300 kW. Cost per watt is $3.19. Estimated output 24,335 kW/year.

The second proposal is probably a better deal. However, keep in mind that LG does not make an all black 300 watt panel. The 300 watt LG panels have a white back sheet.