San Diego Coastal

[albert436]

I'm in Ocean Beach. I live in the front unit of a "2 on 1", in a 850sf house, and am thinking about moving into the back unit. I may just keep one unit always open for family and friends to visit.

The back (alleyside) unit, which is two stories and ~1050sf, has a SW facing roof which is 30ft x 12 ft. There are a few telephone wires which may cast shadows, so I am thinking I will have to do microinverters(?) The other roofs are all very shaded by trees and topography.

I'm home 3 or 4 days a week, and the last couple of months my bills have been ~$150+, though my latest was $225. The gas and electric are usually fairly similar amounts.

Both units have gas wall heaters, this place is old. Thinking about installing mini-split heat pumps.

There is a 3rd meter also, for a shared laundry room with a gas dryer. The washing machine pulls water from the gas water heater in the rear unit, though I almost always wash in cold water.

I'm wondering:
1. What size system will I need? How many panels? What is the output of current panels?
2. How much electricity should I figure the mini-splits will use in place of gas heat which I have been supplementing with small electric space heaters?
3. I've been told that one system cannot be split between more than one meter. That said, I'm trying to think of whether to only set up solar for the back unit, or to also try to set up a system for the front.
3a. I wonder if I could switch the shared laundry electric over to the rear unit meter(?) Or switch the front unit electric over to the rear unit meter? Is that a matter of just swapping some wires around at the panel? (Not that I would even think about doing that myself--too dangerous!!!)
4. The weather is generally mild but we had some awful heat last summer and it can get a bit cold this time of the year.
5. Is there a place for a solar H2O warming system here?
6. Sure I would like to get in under the wire for that think coming in April.
7. Finally, are there any recommendations for solar install companies in San Diego that you might provide? P.S. I don't really want to do that leasing thing.

Sorry this is a bit complicated so I figured I had better just write it all out without too much editing.


THANKS !!!!!!!!!!!!!




my house, north is straight up in this satellite pic.

myhouse.jpg

[J.P.M.]

Albert:

Welcome (back) to the neighborhood.

You need some self education on the basics. Start with a free download and read of "Solar Power Your Home for Dunnies". That education will help you to see through the vendor B.S. and scare tactics to some degree.
Then, get familiar with SDG & E rates and policies.
Then, download your usage (not the bills in $$'s, the usage in kWh) from SDG & E. You'll need that for sizing a system.
Then, get/do an energy audit on your dwelling(s). PV is expensive. The cheapest kWh you'll save is that kWh not used by conservation. an audit will help show youn where to conserve on electricity usage.
If you commit to PV before 04/13/2023, you'll be eligible to be classed under NEM 2.0. After that it'll be NEM 3.0 and not as favorable for PV, but don't be stampeded by fear of missing out.
That SW roof looks good, but know that fire code setbacks imposed by the city and county building codes will most likely limit the that available roof space for PV by maybe 25 - 35% or more.
Given your location, at least you don't have much of an A/C bill.

As a real wild guess for your location and as long-term averages, figure about 1500 - 1700 kWh/yr. of annual production per installed STC kW of PV panels, or ~ 325 kW/yr per m^2 of PV, both with minimal shading. Under those conditions and at current rates for SDG & E schedule DR-SES (the common rate for residential users with a PV system), an installed STC kW of PV might be expected to displace about $650 of your annual electric bill for each mostly shade free STC kW you manage to fit on that roof.
The dummies book will help you fill in the details of what the above means.

[albert436]

billed Kwh etc
9771705884 Energy Usage Graph_01.21.14.pdf

I'm thinking of putting in mini-splits in both units and so I want to take into account using electric for heating in lieu of the current gas wall heaters.

Also if I could just run both units off one meter that would be nice, rather than have two completely separate systems.

I could have used some a/c for a few weeks last summer, it was quite warm. During the summer I set up a portable induction burner and convection toaster oven out on the patio just to keep the house cooler, as it can get kind of close here with the TV and computer running.

So in other words, I think I need to up my estimate of power usage. But yeah JP you are right, it stays much cooler up here than say for example Poway.

Or figuring in the cost of a second inverter and some separate/duplicate wiring -- I'm sure I'll get all that info when the salesperson comes out in a couple of weeks.

So far I've contacted two companies, Cosmic Solar (recommended here) and West Coast, which has many good reviews on Yelp, fwiw. Westcoast texted and emailed me back already, despite it being Saturday afternoon.

JP IIRC you had your install by Sullivan, which I understand is now sadly defunct.

I think I will try to get a few more recommendations on companies and reach out to them, maybe get a total of 3 or 4.

[J.P.M.]

billed Kwh etc
[ATTACH]n437753[/ATTACH]

I'm thinking of putting in mini-splits in both units and so I want to take into account using electric for heating in lieu of the current gas wall heaters.

Also if I could just run both units off one meter that would be nice, rather than have two completely separate systems.

I could have used some a/c for a few weeks last summer, it was quite warm. During the summer I set up a portable induction burner and convection toaster oven out on the patio just to keep the house cooler, as it can get kind of close here with the TV and computer running.

So in other words, I think I need to up my estimate of power usage. But yeah JP you are right, it stays much cooler up here than say for example Poway.

Or figuring in the cost of a second inverter and some separate/duplicate wiring -- I'm sure I'll get all that info when the salesperson comes out in a couple of weeks.

So far I've contacted two companies, Cosmic Solar (recommended here) and West Coast, which has many good reviews on Yelp, fwiw. Westcoast texted and emailed me back already, despite it being Saturday afternoon.

JP IIRC you had your install by Sullivan, which I understand is now sadly defunct.

I think I will try to get a few more recommendations on companies and reach out to them, maybe get a total of 3 or 4.

Understood.

I got 4 quotes back in mid-August, 2013. The first was a low ball from the outfit I knew to be the cheapest of any in n. county. I used that as a benchmark to not go higher with the other three - Baker, Sullivan and Milholland - all of whom do (or did in Sullivan's case) excellent work and all of whom knew me from being the HOA prick who they needed to go through to get stuff into my HOA. Baker wouldn't budge enough on price. Sullivan wanted access to all the solar software I'd written as a condition of doing business or even giving me a quote. Milholland beat that lowball outfit by a bit so they got the job. I got the lowest price/installed STC W paid in CA (at that time) for a turnkey Sunpower system and got it built to my RFP. It's been running flawlessly since 10/13/2013 and so far hasn't missed a watt of potential generation which I ascribe in large measure to the quality of the install and a complete and detailed RFP as well as my sitting on the roof and watching the install.

Don't know if his means anything but in the last month or so, I've seen a few (3 I think) Sullivan Solar trucks rooting around n. county. Maybe they sold off their truck inventory.

[albert436]

Update

1. the usage for the house I live in was 3884kwh for the last 12 months.
2. I got a proposal back for 5.6 and 4.8 Kw systems from the same company so far.

System Size 5.6 kW DC Panels Q.PEAK DUO BLK ML-G10+ 400 Inverters IQ8PLUS-72-2-US [240V] Estimated First Year Production 8,827 kWh AC $20,440 ~$3.65/w

system size 4.8Kw same panels and inverters, est production 7567kwh $17,616 $3.67/w

their estimated production is about 10% higher than the pvwatts estimate for both systems.

I learned there is something called aggregate net metering which would allow me to offset all three meters on the property with credits. So for sure I actually want this sized to account for the back unit which is a little larger (1050sf) than my place. 3rd unit is for laundry with small electricity use. I had not been sure about this and so I don't know if they took the back unit into account, even though I did tell them about it. So is either of these the right size, or do I need to go bigger?

This graph makes me wonder about whether a battery would be a good idea since the usage they portray continues into peak rates. I have heard arguments on both sides of this. How much does a battery cost for a system of the size I need?

Thanks.



powerGraph.jpg

[J.P.M.]

Update

1. the usage for the house I live in was 3884kwh for the last 12 months.
2. I got a proposal back for 5.6 and 4.8 Kw systems from the same company so far.

System Size 5.6 kW DC Panels Q.PEAK DUO BLK ML-G10+ 400 Inverters IQ8PLUS-72-2-US [240V] Estimated First Year Production 8,827 kWh AC $20,440 ~$3.65/w

system size 4.8Kw same panels and inverters, est production 7567kwh $17,616 $3.67/w

their estimated production is about 10% higher than the pvwatts estimate for both systems.

I learned there is something called aggregate net metering which would allow me to offset all three meters on the property with credits. So for sure I actually want this sized to account for the back unit which is a little larger (1050sf) than my place. 3rd unit is for laundry with small electricity use. I had not been sure about this and so I don't know if they took the back unit into account, even though I did tell them about it. So is either of these the right size, or do I need to go bigger?

This graph makes me wonder about whether a battery would be a good idea since the usage they portray continues into peak rates. I have heard arguments on both sides of this. How much does a battery cost for a system of the size I need?

Thanks.



powerGraph.jpg

1.) I did a quick PVWatts run on that roof and I get ~ 1,600 to 1,675 kWh/yr. per installed STC kW as a long term average annual system output.
Use a 10% system loss parameter, 225 degree azimuth and a 20 degree roof slope.

2.) You need to decide what you want to provide power for and that means get the loads for each dwelling/system you want to include. As it is now, it looks like you're considering proving ~ 8,000 kWh/yr for a known ~ 4,000 kWh/yr. load and maybe some at this time unspecified load(s). learn and figure out what loads you want to include.

3.) Prices seem maybe a but high, but given the circumstances, maybe not too bad. Who's the vendor ?

My pitch which almost always falls on deaf ears is that it's never a good idea to buy based on low initial price alone, especially on a long term item in a mostly inaccessible area like a PV system.
Get knowledgeable about what you want and deal with established electrical contractors who have been around a long time befor PV came on the scene.
The equipment can last a long time. a good vendor and install can make the difference between a good system and one with a lot of problems.
Buy cheap, buy twice. Go with a quality vendor and negotiate well. You'll be cheaper and better off down the road. While you're at it, get that roof inspected and serviced if the odds are it won't last 20 years or more. PV done right will last a along time. Give the roof under it the highest probability of lasting as long.

4.) Given that the roof is mostly shade free, I don't see any reason for not using a string inverter and avoiding the KISS problems associated with micros and optimizers. More reliable and probably a bit less $$'s as well.

5.) Once you decide what loads you want to include and equally importantly, what those loads are, you'll be in a much better position to decide if you want battery storage.

FWIW, and since you seem to be asking, my opinion on batteries for you is that it's a no go at this time:
- Batteries are questionably cost effective at this time. They are mostly cost justified to offset peak loads caused by A/C loads. Given your location, you have a much lower A/C load than most and so probably a much lower peak time load.
- The differential per kWh cost between on peak and off peak for SDG & E is ~ $0.33/kWh. You'll need a lot of on peak use to justify ~ $5K - $10K for a battery.
- I personally don't believe batteries are cost effective at this time, nor do I believe that are ready for prime time.
- I might do batteries at some point in the future, but the cost will need to come way down and the systems a lot more standardized. I can always add on in the future.

[albert436]

1.) I did a quick PVWatts run on that roof and I get ~ 1,600 to 1,675 kWh/yr. per installed STC kW as a long term average annual system output.
Use a 10% system loss parameter, 225 degree azimuth and a 20 degree roof slope.

Thanks for that.

2.) You need to decide what you want to provide power for and that means get the loads for each dwelling/system you want to include. As it is now, it looks like you're considering proving ~ 8,000 kWh/yr for a known ~ 4,000 kWh/yr. load and maybe some at this time unspecified load(s). learn and figure out what loads you want to include.

The back unit is more s.f. The upstairs gets hotter than my place, the downstairs equally or more cold. So I'm pretty sure it will take double or more electric usage. Plus I plan to put in mini splits for a/c and heat, which will switch my gas heater energy use to the mini splits. I only see guestimating and I don't think there is a definitive answer, just a best guess.

3.) Prices seem maybe a but high, but given the circumstances, maybe not too bad. Who's the vendor ?

Cosmic, as recommended by someone here. I also have lined up West Coast Solar to come out. Someone else recommended Baker, which has good reviews. Trying to get MIllholland also but they have not yet got back to me.

My pitch which almost always falls on deaf ears is that it's never a good idea to buy based on low initial price alone, especially on a long term item in a mostly inaccessible area like a PV system.

I totally get that ! ! !

Get knowledgeable about what you want and deal with established electrical contractors who have been around a long time befor PV came on the scene.
The equipment can last a long time. a good vendor and install can make the difference between a good system and one with a lot of problems.
Buy cheap, buy twice. Go with a quality vendor and negotiate well. You'll be cheaper and better off down the road. While you're at it, get that roof inspected and serviced if the odds are it won't last 20 years or more. PV done right will last a along time. Give the roof under it the highest probability of lasting as long.

I've heard the same idea expressed as "Buy quality, cry once; buy cheap, cry twice".

4.) Given that the roof is mostly shade free, I don't see any reason for not using a string inverter and avoiding the KISS problems associated with micros and optimizers. More reliable and probably a bit less $$'s as well.

The thing is, there might be a few phone/power lines that cast shadows late in the day. Can't even a small shadow cause all other panels on a string to regulate down? I think they quoted me on micros . . . I'll see what West Coast says when they actually visit the house. Cosmic's analysis is from the internet. A good quick and dirty approach, but not quite as thorough as an on-site inspection IMO.

5.) Once you decide what loads you want to include and equally importantly, what those loads are, you'll be in a much better position to decide if you want battery storage.

FWIW, and since you seem to be asking, my opinion on batteries for you is that it's a no go at this time:
- Batteries are questionably cost effective at this time. They are mostly cost justified to offset peak loads caused by A/C loads. Given your location, you have a much lower A/C load than most and so probably a much lower peak time load.
- The differential per kWh cost between on peak and off peak for SDG & E is ~ $0.33/kWh. You'll need a lot of on peak use to justify ~ $5K - $10K for a battery.
- I personally don't believe batteries are cost effective at this time, nor do I believe that are ready for prime time.
- I might do batteries at some point in the future, but the cost will need to come way down and the systems a lot more standardized. I can always add on in the future.

That's pretty much what I said to the solar broker last night. That was just my gut feeling though, and it is very helpful to have the quantitative analysis.

Plus, I just don't want to outlay that much $$$ just now.

Yeah, "Solar Broker", I had never heard of that before. You would be great in that business, but I suspect you are retired, and not interested in taking on anymore headaches than you get already from riding shotgun for your neighbors and HOA.

[J.P.M.]

Yeah, "Solar Broker", I had never heard of that before. You would be great in that business, but I suspect you are retired, and not interested in taking on anymore headaches than you get already from riding shotgun for your neighbors and HOA.[/I][/B]

[/COLOR][/SIZE]

Solar broker is just another name for a peddler.

FWIW, been there, done that.
Done with that.
My first career of ~ 10 years was as a sales rep. I made a good living peddling industrial process equipment but was bored. Looking around, I got the solar bug.
Cut to the chase, I returned to school and am now retired as an M.E., P.E.
Now I bloviate about alternate energy and spout opinions all over the place. Solar peddlers don't like me because I know some stuff and using John Goodman's character's words in "The Gambler", I've got the type of asset that allows me a lot of freedom.

[albert436]

Solar broker is just another name for a peddler.

FWIW, been there, done that.
Done with that.
My first career of ~ 10 years was as a sales rep. I made a good living peddling industrial process equipment but was bored. Looking around, I got the solar bug.
Cut to the chase, I returned to school and am now retired as an M.E., P.E.
Now I bloviate about alternate energy and spout opinions all over the place. Solar peddlers don't like me because I know some stuff and using John Goodman's character's words in "The Gambler", I've got the type of asset that allows me a lot of freedom.

I thought solar broker was more like a hand-holder.

OK from here on out, I'll refer to companies 1, 2, and 3. Or is there any problem mentioning their names?

Company 1 has now given me three proposals, 5.6kw at $20K (14 panels), 4.8kw at $17K, and 3.2kw for $12kw, these are ballpark figures that come out to around $3.65/w.

Company 2 - I talked a very busy young fellow who off the top of his head told me a 14panel 5.6kw system with the same panels would be around $25K. They are a highly rated company. It comes to around $4.65/watt.

A forum member has had two installs by Company 1 and say he would use them again. So I am scratching my head a bit. I have a third company highest rated company coming out week after next and I'll see what they say.

Any thoughts on the price differential? I'm not in a position to judge how good of an install job they will do . . .




edit:
A couple of follow up questions I think I had better put down before I forget.

1. Would adding batteries later kick you out of your NEM ?
2. The $0.33 differential of peak vs off-peak, that could change if SDGE decides it is losing too much money to solar systems?

another edit:

It just occurred to me to check the reviews on Cosmic, 5/5 on yelp with 98 reviews. That looks pretty good to me.

[J.P.M.]

I thought solar broker was more like a hand-holder.

OK from here on out, I'll refer to companies 1, 2, and 3. Or is there any problem mentioning their names?

Company 1 has now given me three proposals, 5.6kw at $20K (14 panels), 4.8kw at $17K, and 3.2kw for $12kw, these are ballpark figures that come out to around $3.65/w.

Company 2 - I talked a very busy young fellow who off the top of his head told me a 14panel 5.6kw system with the same panels would be around $25K. They are a highly rated company. It comes to around $4.65/watt.

A forum member has had two installs by Company 1 and say he would use them again. So I am scratching my head a bit. I have a third company highest rated company coming out week after next and I'll see what they say.

Any thoughts on the price differential? I'm not in a position to judge how good of an install job they will do . . .




edit:
A couple of follow up questions I think I had better put down before I forget.

1. Would adding batteries later kick you out of your NEM ?
2. The $0.33 differential of peak vs off-peak, that could change if SDGE decides it is losing too much money to solar systems?

another edit:

It just occurred to me to check the reviews on Cosmic, 5/5 on yelp with 98 reviews. That looks pretty good to me.

Answers/Opinions:

1.) Call SDG & E and inquire. I've found a friendly and professional but still persist attitude helps. Smile when you talk to them.
2.) It can always change as can anything else. Look at DR-SES effective rate sheets from a year ago.
SDG & E is like any company in that there are many inputs to their pricing. In spite of what it may seem to a bunch of relatively affluent residential PV system owners, SDG & E or the other CA I.O.U.' s are not out to screw residential PV users. It's not personal, just business. The CA POCO's have lost money on NEM since its inception. It's a lousy business model for them. I'm not a fan of the POCO's by any means but anyone looking at NEM form the POCO's perspective knows it to be a poor way to make money. I suspect anyone who is or has tried to run a business and has an ounce of objectivity would not want to have such a system crammed down their throat.

As for Yelp, besides those places being of questionable veracity, I'm at a loss to understand why folks who know little to nothing about a subject (residential PV in this case) place any reliance on a source that only uses folks who probably know less and certainly no more about the subject except that maybe the salesperson smiled a lot and repeated what the media shills said about PV.
Educate yourself and don't rely on the great unwashed masses for serious decision making information.

[albert436]

Answers/Opinions:

1.) Call SDG & E and inquire. I've found a friendly and professional but still persist attitude helps. Smile when you talk to them.
2.) It can always change as can anything else. Look at DR-SES effective rate sheets from a year ago.
SDG & E is like any company in that there are many inputs to their pricing. In spite of what it may seem to a bunch of relatively affluent residential PV system owners, SDG & E or the other CA I.O.U.' s are not out to screw residential PV users. It's not personal, just business. The CA POCO's have lost money on NEM since its inception. It's a lousy business model for them. I'm not a fan of the POCO's by any means but anyone looking at NEM form the POCO's perspective knows it to be a poor way to make money. I suspect anyone who is or has tried to run a business and has an ounce of objectivity would not want to have such a system crammed down their throat.

As for Yelp, besides those places being of questionable veracity, I'm at a loss to understand why folks who know little to nothing about a subject (residential PV in this case) place any reliance on a source that only uses folks who probably know less and certainly no more about the subject except that maybe the salesperson smiled a lot and repeated what the media shills said about PV.
Educate yourself and don't rely on the great unwashed masses for serious decision making information.

Sorry, let me clarify. I thought you had mentioned somewhere that YOU might have some batteries put in somewhere down the road, and I was asking about whether it would knock you out of your NEM plan.

I'm going to follow your lead and see if some point in the future they come down in price and make more sense economically.

Yeah also found that solarreviews website, I presume you have seen that. My feeling is that while most people may not know much, if there are a few hundred reviews averaging 4.9/5 (or whatever), that's as good a place to start as any. Then there is also the question of negative reviews and the nature of the complaints, and if and how the business owner responded to them.

That's along with the attempts to self-educate along the way. It's going pretty fast here for me because I wasn't planning on getting solar. That spike in gas prices last month pushed me over the line though. And I am working out of town quite a bit of the time so I want to get the ball rolling on this. Maybe not a perfect algorithm for a perfect result, but considering for "Company 1", recommendation from SPT forum member, including a more detailed accounting on asking about his experience, the fact that his friends have also had good results, etc etc., taken along with the ~300 reviews 4.9/5. And I do understand a bit about consumption and production and so forth. My first move is to play dumb when I talk to the vendors, then follow up with simple questions if something they say doesn't sound right. In fact playing dumb is not too hard for me, most people say I am very convincing at that and are not sure they believe I am acting.

That's where things stand right now. Company A guy is coming over Tuesday for an on-site -- should I expect him to wave some papers in my face and tell me I better sign now or I will lose a good deal? Do they usually ask for a signed contract on the home visit? Company B is supposed to come out here the following Tuesday and I will be out of town, so a contractor friend will meet them for me. Company C, that's the guy who gave me a quote that was $5K higher. Company D, I had a good chat with the owner, I think it is a small operation. Interestingly, his first proposal was to use commercial panels to lower costs. There is a question of geometry with my roof however, with the larger panels. I haven't figured out yet the watts per sq meter, or whatever that metric is. But I would get a bit less total Kwh generated.

He brought up another good question, which had to do with Exactly how wide my roof is, and setback rules etc. And making for sure what the measurement is and what will fit. Ie. will a double row of residential panels in portrait mode be too tight of a squeeze? Company A guy hasn't batted an eye about it and seems very sure and has not even brought it up. But I don't mind someone like Company D owner being cautious and thorough, I see it as a sign of professionalism.

But dang I am impatient to get started, because I've got a few days off then out of town again.

So that's what I am thinking at this point.

BTW the Company D commercial panels are 480W and he says they are as big as a door, I'm not sure exactly what the dimensions are however.

I think the usual residential panel is 40"x65" ? He says he can do the residential if the commercials won't work out. Yeah I will have to do some math to figure out that sq meter thing.

[J.P.M.]

Sorry, let me clarify. I thought you had mentioned somewhere that YOU might have some batteries put in somewhere down the road, and I was asking about whether it would knock you out of your NEM plan.

I don't need batteries on NEM 1.0 and tiered rates. I ought to be good for ~ 9.5 more years.

I'm going to follow your lead and see if some point in the future they come down in price and make more sense economically.

Yeah also found that solarreviews website, I presume you have seen that. My feeling is that while most people may not know much, if there are a few hundred reviews averaging 4.9/5 (or whatever), that's as good a place to start as any. Then there is also the question of negative reviews and the nature of the complaints, and if and how the business owner responded to them.

I don't patronize lead generation sites.

That's along with the attempts to self-educate along the way. It's going pretty fast here for me because I wasn't planning on getting solar. That spike in gas prices last month pushed me over the line though. And I am working out of town quite a bit of the time so I want to get the ball rolling on this. Maybe not a perfect algorithm for a perfect result, but considering for "Company 1", recommendation from SPT forum member, including a more detailed accounting on asking about his experience, the fact that his friends have also had good results, etc etc., taken along with the ~300 reviews 4.9/5. And I do understand a bit about consumption and production and so forth. My first move is to play dumb when I talk to the vendors, then follow up with simple questions if something they say doesn't sound right. In fact playing dumb is not too hard for me, most people say I am very convincing at that and are not sure they believe I am acting.

Never ask a question of a vendor that you don't already know the answer to. You'd be amazed at what you learn.

That's where things stand right now. Company A guy is coming over Tuesday for an on-site -- should I expect him to wave some papers in my face and tell me I better sign now or I will lose a good deal? Do they usually ask for a signed contract on the home visit? Company B is supposed to come out here the following Tuesday and I will be out of town, so a contractor friend will meet them for me. Company C, that's the guy who gave me a quote that was $5K higher. Company D, I had a good chat with the owner, I think it is a small operation. Interestingly, his first proposal was to use commercial panels to lower costs. There is a question of geometry with my roof however, with the larger panels. I haven't figured out yet the watts per sq meter, or whatever that metric is. But I would get a bit less total Kwh generated.

If a panel has, say, 20% STC efficiency, it will produce 20 % of the STC input/area, or 1,000 W/m^2**.20 = 200 W/m^2, regardless of physical size of the panel. Bigger panels will produce more output, but you'll get fewer of them into a given space.
BTW, The "area efficiency" that Sunpower plays up is no more than a scam. All arrays of the same STC size using reasonable quality panels that are well made and professionally installed will produce about or close to the same amount of energy over the course of a year in the same location, orientation and conditions. The higher STC rated panels will do so in a smaller area. That's about it, and the area decrease isn't that much, like ~ 5% less or so. That "area efficiency" that Sunper touts to the heavens about is a scam.
Smaller (physical size) panels (300 STCW vs, say, 480 STC W) may allow a bit more STC wattage on your roof because they aren't as "lumpy", but at the expense of probably a bit more wiring and assembly.

He brought up another good question, which had to do with Exactly how wide my roof is, and setback rules etc. And making for sure what the measurement is and what will fit. Ie. will a double row of residential panels in portrait mode be too tight of a squeeze? Company A guy hasn't batted an eye about it and seems very sure and has not even brought it up. But I don't mind someone like Company D owner being cautious and thorough, I see it as a sign of professionalism.

I mentioned fire setbacks in a prior post. Look into it by calling the S.D. building dept. it's a big deal.

But dang I am impatient to get started, because I've got a few days off then out of town again.

So that's what I am thinking at this point.

BTW the Company D commercial panels are 480W and he says they are as big as a door, I'm not sure exactly what the dimensions are however.

Dimensions are always on panel data sheets.

I think the usual residential panel is 40"x65" ? He says he can do the residential if the commercials won't work out. Yeah I will have to do some math to figure out that sq meter thing.

Holler as your needs dictate.

[Ampster]

........... I was asking about whether it would knock you out of your NEM plan........

If I understand the issue in SDGE territory with peak rates as high as $0.81/per kWh and as low as $0.19/kWh those rate differentials can make batteries an optimal way to reduce an energy bill depending of one's use case. Batteries can allow one to reduce or eliminate peak rate consumption. A lot may depend of your use case but as far as I understand the rules, a battery installation only requires a building permit unless one is applying for subsidy funds such as SGIP funding. Clearly this is a gray area in terms or what the IOUs would like you to believe. The only rules that prevent charging from the grid, are those noted above and the Investment Tax Credit. Once the energy passes through your meter you are free to use it as you please. That is my answer to your question.

[albert436]

Another question. Is it OK to put panels from the same system on two separate units ?

[J.P.M.]

If I understand the issue in SDGE territory with peak rates as high as $0.81/per kWh and as low as $0.19/kWh those rate differentials can make batteries an optimal way to reduce an energy bill depending of one's use case.

It's usually the difference between on peak and off peak rates for a day, summed over some period of , say, 30 or 365 days that are used to determine the cost effectiveness of a battery system.

Also, the optimal and most cost-effective way to reduce an energy bill is through conservation.
Fact of life: The 100% savings on unused energy are impossible to beat.
Time shifting of loads without batteries is probably the next most cost effective.