Thoughts on this SolarCity proposal? **Photos inside**

[J.P.M.]

After reading this write up: http://energyinformative.org/are-sol...ral-inverters/

Sounds like micro inverters are better based on this article and also the mono crytalline panels are better. My husband doesn't like what is said about the potential life threatening issue with the central inverter
"Solar panels are connected in series before they are fed into a central inverter, typically with an effective nominal rating of 300-600 VDC (volts of direct current). This current is potentially life threatening.

Micro-inverters eliminate the need for high voltage DC wiring, which improve the safety for both solar installers and system owners."

So he basically say no to Sun Power or Kyocera since these two system comes with a central inverter and to get the micro inverter in place of the central, and extra $3,000 on top of already higher cost system.

I was almost ready to go with the Kyocera system if the company is willing to lower the price a bit. But now after reading this article, I should go with the least expensive system which is the monocrystalline with micro inverter. I am wondering if this article is biased? Any thoughts about the DC wiring?

The article is a sales pitch for peddlers masquerading as experts. Follow the money. Folks on this forum may be rough around the edges sometimes, but they also, except for a couple of financial slug types, have no skin in the game, nothing to sell and collectively, while not always bullet proof on answers, usually do pretty good.

BTW, for the most part, central inverter systems usually cost less than micros.

[russ]

pay a 2000$ down seems good

Based on what? Don't post just to post. If you have some points to help then great - if not then do not.

Maybe things are different in China?

[lideyan@gmail.com]

pay a 2000$ down seems good

pay a 2000$ down seems good

Hello all, first post here so be gentle

Solar City came to me and made the pitch. See photos of the proposal (just the initial pitch) that they sent to me.

Also attached is my typical bill, which usually runs about 120ish per month.

So there is either the pay nothing down plan that puts us at 10.6 cents per kWh with yearly 2.9% increases
or the other pay nothing down plan that puts us at 15 cents per kWh with no increases for 20 years.

Or I could give them 2,000$ down and lock in 10.7 kWh for 20 years.


Any thoughts on this?

downsides to this?

[russ]

Sounds like micro inverters are better based on this article and also the mono crytalline panels are better. Why better?

My husband doesn't like what is said about the potential life threatening issue with the central inverter
"Solar panels are connected in series before they are fed into a central inverter, typically with an effective nominal rating of 300-600 VDC (volts of direct current). This current is potentially life threatening. 120 volts from your house plug is life threatening - no big deal and a really misleading statement.

Micro-inverters eliminate the need for high voltage DC wiring, which improve the safety for both solar installers and system owners." Why? It changes the wiring requirements but to say they increased the safety is not really true - for example, the incomer to my main panel is 430 volt 3 phase - You are just more careful when sticking fingers in there.

So he basically say no to Sun Power or Kyocera since these two system comes with a central inverter and to get the micro inverter in place of the central, and extra $3,000 on top of already higher cost system. Your money but the logic behind that is faulty.

I was almost ready to go with the Kyocera system if the company is willing to lower the price a bit. But now after reading this article, I should go with the least expensive system which is the monocrystalline with micro inverter. I am wondering if this article is biased? Any thoughts about the DC wiring?

Biased? Don't know about biased but not really correct

Microinverters place the heart of your system on the roof top where it is much hotter than what this bunch complains about for the central inverter.

With micros you have many more points of failure - all on the roof top and difficult to access.

Warranty - Enphase has already reduced their warranty - labor now not included - if the installer warrants something you have to ask if he will be around next month let alone in 10 years.

If you have a shade problem then micro inverters are called for - no shade then there is no good reason for them.

Many central inverters offer an extended warranty for a small amount - that makes them close to the microinverters in that area.

[skinnywalletana]

is this write up seems trust worthy or biased?

1.) The $3.25-$3.50 is BEFORE rebates - at least in CA.

2.) Some vendors push micros perhaps because:
- They make more money.
- There may be shade issues.
- Some cust. want them because of monkey see - monkey do attitudes or-
- Customers got talked into them by some peddler who spotted a solar ignorant customer.

To me, without shade problems they're no more than more money for more failure points and some horror stories about warranty claims. My engineering opinion is there are better ways to do it than micros.

3.) Look at your monthly usage and, as a 1st approx. size a system that gets rid of all but the tier 1 & 2 usage. Forget the 75% thing. That may be close, but its a bogus way to do it. Also, do not assume that all months have the same # of kWh in each level. Study past bills looking at tier levels and # of kWh. in each level, summer vs. winter. Better yet, study your POCO's rate structure and learn the impact of conservation or solar as it applies to your electric bill.

4.) On leases and maint: Although solar elec. gen. equip. has not been around for 20 or so years on a common basis, I'm of the opinion, which I believe is shared by more than a few, that solar electric will need about as much maint. as, say, as a first approximation, your hot water tank and probably much less than, say, your HVAC equipment. The maint. scare is a red herring, preying on people's fear generated by ignorance of an unknown - the future. The same methods and logic are used to peddle overpriced extended warranties - exaggerate the possible negative outcomes and let people's own emotional fear of the unknown (the future) sell themselves on what they don't need.

There MAY be valid reasons to lease (and damn few IMO), but "free" or "trouble free" maintenance is not one of them.

I live in an HOA with about 60+ installs. I pretty much watch them like a hawk. 6 yrs. on and the 2 problems I'm aware of both happened within a month or 2 of startup and were quickly resolved. Besides, mfr. and or dealer/installer warranties will do the same thing. Inverter warranties run about 10 yrs. And, as you say, since you plan on staying 10 yrs - well - why worry about maint. ?

5.) Important: If you get panels NEVER HOSE/CLEAN THEM WHEN THEY ARE HOT, OR WHEN THE SUN IS HIGH - BAD THINGS HAPPEN !

6.) Most of the panels you may be considering are about equal physical size - something like ~ 41" X 62" +/- a bit. Panel nameplate (S.T.C.) Wattages, depending on mfr. and type w/in mfr. line vary from about 250 to 300 Watts for decent panels and about 327 to 345 Watts/panel for the common Sunpower panels - mostly about the same physical size - that 41" X 62".
Respectfully, if you're not cramped for space don't worry about individual panels for physical size and Wattage. Concentrate, at least initially, on total system Wattage and total resulting physical dimensions. And don't oversize if you're concerned about cost effectiveness.

Equal electrical sized systems (Wattage) have about equal initial annual output - Sunpower included. Therefore, it makes some sense to, as I suggested, put everything on a $/nameplate (S.T.C.) basis. That's the common basis. Not # of panels. Just how much money each nameplate Watt will cost to put on your roof. After you get that, you'll have a firmer footing to compare costs vs. how much you want to spend for what you think is important.

Sunpower puts out the same amount of yearly generating capacity in a smaller area and does it for more money. The lower per yr. degradation/yr. of the Sunpower panels will produce about a 5% or so lower LCOE over 25 yrs. So, if you plan on a 25 yr. stay, a 5 % up front premium may be justifiable. For your 10 yr. scenario, maybe not. IMO, the Sunpower warranty may be a better, but it's overkill for most applications.

After reading this write up: http://energyinformative.org/are-sol...ral-inverters/

Sounds like micro inverters are better based on this article and also the mono crytalline panels are better. My husband doesn't like what is said about the potential life threatening issue with the central inverter
"Solar panels are connected in series before they are fed into a central inverter, typically with an effective nominal rating of 300-600 VDC (volts of direct current). This current is potentially life threatening.

Micro-inverters eliminate the need for high voltage DC wiring, which improve the safety for both solar installers and system owners."

So he basically say no to Sun Power or Kyocera since these two system comes with a central inverter and to get the micro inverter in place of the central, and extra $3,000 on top of already higher cost system.

I was almost ready to go with the Kyocera system if the company is willing to lower the price a bit. But now after reading this article, I should go with the least expensive system which is the monocrystalline with micro inverter. I am wondering if this article is biased? Any thoughts about the DC wiring?

[J.P.M.]

I do plan to get at least one more quote. But unless I get a quote for the same panels sun power or kyocera, it is hard to compare apples to apples. As mentioned early in my first post, I got the quote for a 6.36 kwh sytem canadian solar but it cost less than these 2 system and use microinverter.

1.) The $3.25-$3.50 is BEFORE rebates - at least in CA.

2.) Some vendors push micros perhaps because:
- They make more money.
- There may be shade issues.
- Some cust. want them because of monkey see - monkey do attitudes or-
- Customers got talked into them by some peddler who spotted a solar ignorant customer.

To me, without shade problems they're no more than more money for more failure points and some horror stories about warranty claims. My engineering opinion is there are better ways to do it than micros.

3.) Look at your monthly usage and, as a 1st approx. size a system that gets rid of all but the tier 1 & 2 usage. Forget the 75% thing. That may be close, but its a bogus way to do it. Also, do not assume that all months have the same # of kWh in each level. Study past bills looking at tier levels and # of kWh. in each level, summer vs. winter. Better yet, study your POCO's rate structure and learn the impact of conservation or solar as it applies to your electric bill.

4.) On leases and maint: Although solar elec. gen. equip. has not been around for 20 or so years on a common basis, I'm of the opinion, which I believe is shared by more than a few, that solar electric will need about as much maint. as, say, as a first approximation, your hot water tank and probably much less than, say, your HVAC equipment. The maint. scare is a red herring, preying on people's fear generated by ignorance of an unknown - the future. The same methods and logic are used to peddle overpriced extended warranties - exaggerate the possible negative outcomes and let people's own emotional fear of the unknown (the future) sell themselves on what they don't need.

There MAY be valid reasons to lease (and damn few IMO), but "free" or "trouble free" maintenance is not one of them.

I live in an HOA with about 60+ installs. I pretty much watch them like a hawk. 6 yrs. on and the 2 problems I'm aware of both happened within a month or 2 of startup and were quickly resolved. Besides, mfr. and or dealer/installer warranties will do the same thing. Inverter warranties run about 10 yrs. And, as you say, since you plan on staying 10 yrs - well - why worry about maint. ?

5.) Important: If you get panels NEVER HOSE/CLEAN THEM WHEN THEY ARE HOT, OR WHEN THE SUN IS HIGH - BAD THINGS HAPPEN !

6.) Most of the panels you may be considering are about equal physical size - something like ~ 41" X 62" +/- a bit. Panel nameplate (S.T.C.) Wattages, depending on mfr. and type w/in mfr. line vary from about 250 to 300 Watts for decent panels and about 327 to 345 Watts/panel for the common Sunpower panels - mostly about the same physical size - that 41" X 62".
Respectfully, if you're not cramped for space don't worry about individual panels for physical size and Wattage. Concentrate, at least initially, on total system Wattage and total resulting physical dimensions. And don't oversize if you're concerned about cost effectiveness.

Equal electrical sized systems (Wattage) have about equal initial annual output - Sunpower included. Therefore, it makes some sense to, as I suggested, put everything on a $/nameplate (S.T.C.) basis. That's the common basis. Not # of panels. Just how much money each nameplate Watt will cost to put on your roof. After you get that, you'll have a firmer footing to compare costs vs. how much you want to spend for what you think is important.

Sunpower puts out the same amount of yearly generating capacity in a smaller area and does it for more money. The lower per yr. degradation/yr. of the Sunpower panels will produce about a 5% or so lower LCOE over 25 yrs. So, if you plan on a 25 yr. stay, a 5 % up front premium may be justifiable. For your 10 yr. scenario, maybe not. IMO, the Sunpower warranty may be a better, but it's overkill for most applications.

[russ]

I do plan to get at least one more quote. But unless I get a quote for the same panels sun power or kyocera, it is hard to compare apples to apples. As mentioned early in my first post, I got the quote for a 6.36 kwh sytem canadian solar but it cost less than these 2 system and use microinverter.

Forget the brand - there is a wide range of manufacturers that are more or less equal for your purpose.

[skinnywalletana]

Thanks for your repsonse

Lots to consider. Briefly, iIn order of your paragraphs:

1.) I can't do much except to suggest put everything on a $'s /nameplate Watt basis paid to the vendor before rebates/tax credits are considered. Put everything on an equal footing costwise for starters.

I have been reading that the cost should be about $3.25 to $3.50 per watt, but is that after the rebate or before?[/COLOR]

2.) As Russ said: No shade-->> string inverter. Less $$'s than micros and fewer failure points. SMA's are pretty robust

so why are all these companies selling microinverters when shade is not a problem? and when I asked if I want micro inverter, it is an extra $3k. all quotes from my neighbor is with microinverters and she has no shade issue either.

3.) Equal (electrical) sizes systems in the same location, azimuth and elevation will, initially produce about equal yearly output, regardless of panel mfr. BTW, it's the (electrical) size of the system that counts, not the # of panels or each panel's Wattage.
The most cost effective size is the one that produces the lowest Levelized Cost Of Electricity (LCOE) over the time period set by the owner/user(s). To figure that out requires some decision making, some input about finances and some assumptions about the future and the user's place in that future. Depending on your utility rate structure and cost, and realistic SWAG's about future rate direction, a 100% offset of a bill may likely not be as cost effective as, say, offsetting all but the lowest tiers of usage. That's what LCOE is all about.

It does make sense to bring it down to Tier 2 as it is fairly cheap $.17, but am only allowed a up to a total of 420 kwh in this Tier 1 & 2 range, then it goes up to $.31. So it looks like I may still be in tier 3 in some months if I go with Kyocera as it is producing about 75% of my usage.

The buy vs. lease question has been the source of, let's say, "spirited" discussions on this forum for some time. I'd only offer to keep an open, critically thinking mind and attitude, do your homework, read prior threads on this forum, pay your money and take your best shot.

My neighbor is concerned with maintenance and as such, rather lease. Is there really a maintenance issue? It almost seems like if you say you are thinking of leasing, they said yes, you don't have to worry about maintenance. If you say you going to purchase, they say there isn't really anything to maintain. I did get some info as to maintanence and this is what he said " there is no maintenance on your side unless you choose to hose the panels off for slightly better production in the range of 3-5%"

Sunpower will leave a smaller footprint on your roof than other panels. that's "area efficiency". For that you pay a price premium. That premium was about 15-25% ROUGHLY.

He said they are roughly the same (sun power is shorter but little wider?), but either one my roof can only accommodate 24 panels. Asked for a layout and only saw 21? Hmm? so waiting to get a response.

There is some anecdotal evidence that price differential is coming down some recently. Over 25 yrs. or so, S.P.'s lower yearly degradation will amount to a 5% or so lower LOCE, so some $$ premium MAY be warranted, but probably not much more than that 5%. The S.P. warranty may be better, IMO, it's overkill and expensive for what you get, but opinions vary. As stated above, equal sized systems , same location and orientation - close to same output. S.P's great stuff, maybe not worth the premium. Pay your money, take your choice. Solar's an appliance, not a lifestyle. If roof real estate is dear to your heart, S.P. will save the space it. If saving $$'s count, other panels may be more cost effective.

I agree that it is steep for the little extra 1.848 kwh and longer warranty. I planned on staying here for about 10 more years, so kyocera recoup is about 5-6 years make sense as oppose to 9 years.

4.) I don't understand your #'s 23.63,34, etc. I'd suggest if you don't know why usage is going up, get it checked out. Also, in my experience, I've found that use patterns and family habits and priorities play a larger role in energy consumption than house size.

will do that.

5.) The last 2 para.: See my prior text above and, your salesperson is blowing smoke were the sun don't shine. Do more homework. Soon you'll know more than the peddlers and when you get more quotes you'll be able to answer most of your own questions and ask embarrassing one's of the peddlers. Ask the rest of the questions here.

I do plan to get at least one more quote. But unless I get a quote for the same panels sun power or kyocera, it is hard to compare apples to apples. As mentioned early in my first post, I got the quote for a 6.36 kwh sytem canadian solar but it cost less than these 2 system and use microinverter.

[skinnywalletana]

Thanks for your repsonse

1) Where are you located? With tiered rates it generally makes more sense to knock off the top tiers but not go for 100%.

I am in southern california. Tier 1 ($.14) 323 kwh, Tier 2 ($.17) 97 kwh, Tier 3 ($.31) 226 kwh, Tier 4 ($.31) 663. That is my current bill.
2) Do you have a shade problem? If not then microinverters are a waste of money.

No. But most companies are quoting micro inverter (my neighbor got 3 quotes and they are all micro and she has no shade problem either)

3) It sounds like you have a rather stupid salesman - from the final paragraph what return are they talking about?

initial investment and total savings (projected) for Kyrocera ($17,536 and $142,325, respectively)
initial investment and total savings (projected) for sun power ($26,364 and $171,364)

4) You can always have a meter checked - probably 99% of the time (or more) the meter is fine. It is difficult to compare to a neighbor - your appliances and toys are different.

I will do that. Thanks.

[J.P.M.]

I have quotes from 2 companies. One offers sunpower (7.848 kw) and kyocera (6.0 kw). 24 panels would fit on our roof. Cost is $26,364 and $17,536 respectively after 30% federal rebate and use SMA inverter The other company sells the 24 solar panels of canadian solar 265 w for $13,160 with quote of $1.3 per watt for install. So with federal rebate, it looks like it will be $15K with Enphase M-215. My past year usage is $255 average per month and 12,700 kw this past year. My question is which company and solar panels are best for your money? Both companies seem reputable.

what is your take on micro inverter vs SMA inverter? Been reading up on this and can't seems to know which way to go. But if I want microinverter for the sunpower or kyocera, it would be additional $3,000.

For kyrocera, production only 9,493 and sun power 12,596. So wouldn't it make sense to get sun power since it is producing 99% and take 9 year to recoup vs kyrocera 75% and take 6 years? Is there bigger advantage buying vs leasing if one has the money to buy? What about the type of panels? Area the panels all roughly the same or some are better than others?

Based on my usage chart, 2 years ago, 23.63, last year, 34, and this year 40.91, so it is continue to go up. I don't think I am using a whole lot more each year, so I can't figure out why it is going up so much each year. I have already changed most of my house lighting to LED lights. My fridges are under 10 years old, new washer and dryer. My neighbor with the same number of household appliances and kids, same exact house size, their electricity bills is about $170 while mine is $255. Would it be worth while asking the electric company to come out to see if the meter is working correctly?

While I do see that the Sunpower is a lot more expensive to purchase for only 1.8 Kw more, the warranty for these panels are 25 years warranty as oppose to Kyocera, only 10 years. inverter for both are 20 years. There is no more space to add more panels on either system. So you still think it is too steep for that additional warranty? It is very unlikely I will have excess production with Kyocera as it is only producing 75% of my usage now, and looks like my usage will continue to go up, whereas Sunpower is projected to meet 99% of my production now. I was told I will get credit, even exchange.

From the worksheet I was provided with, it was said that the Kyocera has a rate of return of 21% as oppose to Sun power only 17%. Don't know how they came up with the figure and the guy can't seem to explain as it was computer generated. I was told that that even split in customers for both panels, but solar guy thinks I should go with Kyocera.

Lots to consider. Briefly, iIn order of your paragraphs:

1.) I can't do much except to suggest put everything on a $'s /nameplate Watt basis paid to the vendor before rebates/tax credits are considered. Put everything on an equal footing costwise for starters.

2.) As Russ said: No shade-->> string inverter. Less $$'s than micros and fewer failure points. SMA's are pretty robust.

3.) Equal (electrical) sizes systems in the same location, azimuth and elevation will, initially produce about equal yearly output, regardless of panel mfr. BTW, it's the (electrical) size of the system that counts, not the # of panels or each panel's Wattage.
The most cost effective size is the one that produces the lowest Levelized Cost Of Electricity (LCOE) over the time period set by the owner/user(s). To figure that out requires some decision making, some input about finances and some assumptions about the future and the user's place in that future. Depending on your utility rate structure and cost, and realistic SWAG's about future rate direction, a 100% offset of a bill may likely not be as cost effective as, say, offsetting all but the lowest tiers of usage. That's what LCOE is all about.
The buy vs. lease question has been the source of, let's say, "spirited" discussions on this forum for some time. I'd only offer to keep an open, critically thinking mind and attitude, do your homework, read prior threads on this forum, pay your money and take your best shot.
Sunpower will leave a smaller footprint on your roof than other panels. that's "area efficiency". For that you pay a price premium. That premium was about 15-25% ROUGHLY. There is some anecdotal evidence that price differential is coming down some recently. Over 25 yrs. or so, S.P.'s lower yearly degradation will amount to a 5% or so lower LOCE, so some $$ premium MAY be warranted, but probably not much more than that 5%. The S.P. warranty may be better, IMO, it's overkill and expensive for what you get, but opinions vary. As stated above, equal sized systems , same location and orientation - close to same output. S.P's great stuff, maybe not worth the premium. Pay your money, take your choice. Solar's an appliance, not a lifestyle. If roof real estate is dear to your heart, S.P. will save the space it. If saving $$'s count, other panels may be more cost effective.

4.) I don't understand your #'s 23.63,34, etc. I'd suggest if you don't know why usage is going up, get it checked out. Also, in my experience, I've found that use patterns and family habits and priorities play a larger role in energy consumption than house size.

5.) The last 2 para.: See my prior text above and, your salesperson is blowing smoke were the sun don't shine. Do more homework. Soon you'll know more than the peddlers and when you get more quotes you'll be able to answer most of your own questions and ask embarrassing one's of the peddlers. Ask the rest of the questions here.

[russ]

1) Where are you located? With tiered rates it generally makes more sense to knock off the top tiers but not go for 100%.

2) Do you have a shade problem? If not then microinverters are a waste of money.

3) It sounds like you have a rather stupid salesman - from the final paragraph what return are they talking about?

4) You can always have a meter checked - probably 99% of the time (or more) the meter is fine. It is difficult to compare to a neighbor - your appliances and toys are different.

[skinnywalletana]

I need help figuring these solar proposals. Any thoughts? Thanks

I have quotes from 2 companies. One offers sunpower (7.848 kw) and kyocera (6.0 kw). 24 panels would fit on our roof. Cost is $26,364 and $17,536 respectively after 30% federal rebate and use SMA inverter The other company sells the 24 solar panels of canadian solar 265 w for $13,160 with quote of $1.3 per watt for install. So with federal rebate, it looks like it will be $15K with Enphase M-215. My past year usage is $255 average per month and 12,700 kw this past year. My question is which company and solar panels are best for your money? Both companies seem reputable.

what is your take on micro inverter vs SMA inverter? Been reading up on this and can't seems to know which way to go. But if I want microinverter for the sunpower or kyocera, it would be additional $3,000.

For kyrocera, production only 9,493 and sun power 12,596. So wouldn't it make sense to get sun power since it is producing 99% and take 9 year to recoup vs kyrocera 75% and take 6 years? Is there bigger advantage buying vs leasing if one has the money to buy? What about the type of panels? Area the panels all roughly the same or some are better than others?

Based on my usage chart, 2 years ago, 23.63, last year, 34, and this year 40.91, so it is continue to go up. I don't think I am using a whole lot more each year, so I can't figure out why it is going up so much each year. I have already changed most of my house lighting to LED lights. My fridges are under 10 years old, new washer and dryer. My neighbor with the same number of household appliances and kids, same exact house size, their electricity bills is about $170 while mine is $255. Would it be worth while asking the electric company to come out to see if the meter is working correctly?

While I do see that the Sunpower is a lot more expensive to purchase for only 1.8 Kw more, the warranty for these panels are 25 years warranty as oppose to Kyocera, only 10 years. inverter for both are 20 years. There is no more space to add more panels on either system. So you still think it is too steep for that additional warranty? It is very unlikely I will have excess production with Kyocera as it is only producing 75% of my usage now, and looks like my usage will continue to go up, whereas Sunpower is projected to meet 99% of my production now. I was told I will get credit, even exchange.

From the worksheet I was provided with, it was said that the Kyocera has a rate of return of 21% as oppose to Sun power only 17%. Don't know how they came up with the figure and the guy can't seem to explain as it was computer generated. I was told that that even split in customers for both panels, but solar guy thinks I should go with Kyocera.

[njguy]

I wanted to like Solar City when they gave me my quote but just thought it was a bit shady compared to others. They guy was nice and all but they wanted to install panels on the northwest facing side of my house which basically gets no sun in New Jersey from December through February. Just felt they were trying to do that to boost price.

[J.P.M.]

I found this last night on NREL website. It is the 25 year average escalation rates for different regions of the US. The summary is that across the US over the last 25 years the escalation rate is below 1%. One caveat is that these rates are commercial and I don't know how that relates to residential rates.

us_map_cost_escalations_title.pdf

Makes me question using 5% or even 3% in any ROI assumption.

I've seen this more than once and it exposes the peddlers crap about bogus rate escalation for the B.S. that it is.

A couple/3 comments:

1.) The residential side is a bit higher, but still generally between 1-2 %. My guess for part of that situation is that while companies do usually use more power than residential users, they also keep a better handle on costs and apply some rate pressure on POCOs.

2.) The peddlers and opinion spinners will say something like: " Yea, but that's for 25 years, look at the last 3, or look at the last 10 years." Or, "Over the last 25 yrs. your rates have gone up 65%" - which translates to 2% compounded annually, but looks worse.

3.) a figure for average rate increase over past years is not only no guarantee of the future, but an average is usually much different than any particular year's increase.

[prhamilton]

I found this last night on NREL website. It is the 25 year average escalation rates for different regions of the US. The summary is that across the US over the last 25 years the escalation rate is below 1%. One caveat is that these rates are commercial and I don't know how that relates to residential rates.

us_map_cost_escalations_title.pdf

Makes me question using 5% or even 3% in any ROI assumption.