Paradigm shift needed in how we view solar panel cost vs performance?

[Bzzy56]

I strongly recommend a series pair of 30 gal gas heaters. Set the first for 90F and the 2nd for 120F Neither gets thermal shock and you still have 2 burners going if you HAVE to fill the hot tub. Circ pump only on the 120 tank. I ran this in my old house for 15 years, really low gas bills too

Thanks for the idea Mike I actually did this in our last house with a pair of 42 gallon tanks set with offset temps and worked great!

For his house I can't run a pair of small tanks....I tried running just one 80 gallon HW tank and my wife drained it filling our jacuzzi tub and couldn't put enough hot water to fill it ;>(

[J.P.M.]

Dang....bitch-slap accepted lol but you'll find that I am a quick study! No more Kw Captain...ONLY Kwh from now on!!!

I tend to disagree a bit here and again, this is why I intuitively without facts and data have suspected the DWH recirculation system as a chief contributor (until I see what you have now provided, THANKS!) rather than thinking that the energy conservation isn't of a decent quality or working......this Winter we recorded outside our windows a record low of 23F early in the AM so needless to say we've had a bit of an unseasonably cold AZ Winter. For that fact, the Estrella Mountains which are next to us even received a generous amount of snow during one week! This is nearly unheard of for decades around here but my point for bringing this up is our house temperature never got below 70 degrees ALL Winter long. I have our garage, MH stall and 40x40 shop insulated as well and these area's never dipped below the low 60's all Winter so I think there is some good here.

Nonetheless, to specifically answer your comments regarding the DWH recirculation system, I likely have several hundred feet of uninsulated hot water pipe in the attic space that I have planned on insulating after viewing these energy consumption bills. For example, there is one dedicated 3/4" line running specifically from the HW tank to the Jacuzzi tub in the master bath that is 80' long just in the attic space not to mention 80' back to the HW tank! This doesn't account for the other HW lines nor the line going out to my shop or outdoor BBQ.

Thank you for the reply.

Indeed, a DHW recirc. system is an energy hog. First thing I'd do is get rid of it. It's a waste. On a recirc. system, every hot water tap needs 2X as much water line as normally needed. AND both lines, supply and return are always at temperature. In effect, you have a 20 ft.^2 radiator losing heat for every 100 ft. of 3/4" line. To make matters worse, a good part of that heat that is lost is heating a good part of the rest of the dwelling. That adds to the air conditioning load in A/C season. A double whammy.

After I goy rid of the recirc. system, lines, pumps and controls, next thing I'd do is insulate all the remaining hot water supply lines. The first measure of getting rid of the recirc. system will save more energy than the second, but getting rid of the recirc. system all together will save so much that insulating the remaining hot water supply lines, while significant and cost effective, will seem like a relatively small saving in comparison to the savings you'll see from dumping the energy hog recirc. system.

I don't think we disagree on the value of conservation, and I did not mean to imply that energy conservation efforts are not worthwhile. To that end, I can imagine what your usage might be without those modern conservation measures. I'm one of the biggest advocates you're likely to find for not using energy via lifestyle and sensible conservation efforts before even considering ways to get more energy (such as residential PV) to offset an horrendous and usually self inflicted high energy bill. This isn't meant as a judgement on your lifestyle- absolutely NOMB - but 75,000 kWh/yr. is a huge usage, particularly for all the energy saving measures you have applied. I know Phoenix is hot. I lived in the Palm Springs area for several years. The climates are quite similar. Your dwelling is quite a bit larger than mine was - I had ~ 2,600 ft.^2, but I never went past 11,000 kWh/yr. Again, not a knock on you, but your usage is so large, I've got to believe reducing your use will pay bigger dividends and make PV, if/when you do go that way, a lot more cost effective. One thing: FWIW, my A/C thermostat never got below 78 F in cooling season. I also had a whole house fan for the shoulder seasons that operated mostly at night.

[Bzzy56]

We're on the same page J.P.M., I have also initiated actions for the Utility to test the existing meter head and they have agreed to actually replace it with a different type of meter that will allow more precise readings....not sure exactly what that means in terms of it's capabilities but I do have a 400 Amp service and the meter reads are only in 40 Kwh increments for daily usage. I can drill down in the detail of my daily usage to observe hour by hour consumption.

I just wish I had a clue before I even had the plumber add all the extra frickin piping for the recirc system what the impact of it would be but nowhere do I see that spelled out...oh well, live and learn I guess.

Thanks again for all of your energy consumption insights.....now back to my original question though, when viewing cost of just the panel portion of the solar system I know you mentioned not get the "gold plated" ones but where is a "reasonable" place to draw the line because as I started this thread, it seems that a person could be money ahead just flat replacing panels in 10-12 years based on technology improvements and economies of scale that will continue to drive price down.

[Ampster]

Before you dump the entire recirc system make sure you evaluate the cost of the water you are dumping down the drain. I put it a demand recirc system so I just push a button as I am getting ready to shower and the shower is hot when I am ready to go. My first one was hard wired but the last one was wireless and easy to retrofit. I set the timer just long enough to bring hot water to the tap, and not waste heat recirculating it back to the tank. The pumps take very little electricity.

[Mike90250]

You can simply unplug the recirc system and very little flow / loss will occur. Cold weather, you may have to drain pipes in unheated spaces, or power it back up. There are also demand sensors, you "burp" the hot water for a second, and shut off. Sensor notices flow, and kicks on pump for 5 min. in 1 min you have instant hot water.

[Bzzy56]

Before you dump the entire recirc system make sure you evaluate the cost of the water you are dumping down the drain. I put it a demand recirc system so I just push a button as I am getting ready to shower and the shower is hot when I am ready to go. My first one was hard wired but the last one was wireless and easy to retrofit. I set the timer just long enough to bring hot water to the tap, and not waste heat recirculating it back to the tank. The pumps take very little electricity.

Very valid pint, however, I am on a well so other than the cost to power the pump for a few more gallons of water at 0.05 cents/Kwh it's likely pretty cheap

[Ampster]

.........There are also demand sensors, you "burp" the hot water for a second, and shut off. Sensor notices flow, and kicks on pump for 5 min. in 1 min you have instant hot water.

I will have to look into those. Perhaps a lot easier than wireless, which is cobbled together from various timer relays and wireless switches.

[J.P.M.]

We're on the same page J.P.M., I have also initiated actions for the Utility to test the existing meter head and they have agreed to actually replace it with a different type of meter that will allow more precise readings....not sure exactly what that means in terms of it's capabilities but I do have a 400 Amp service and the meter reads are only in 40 Kwh increments for daily usage. I can drill down in the detail of my daily usage to observe hour by hour consumption.

I just wish I had a clue before I even had the plumber add all the extra frickin piping for the recirc system what the impact of it would be but nowhere do I see that spelled out...oh well, live and learn I guess.

Thanks again for all of your energy consumption insights.....now back to my original question though, when viewing cost of just the panel portion of the solar system I know you mentioned not get the "gold plated" ones but where is a "reasonable" place to draw the line because as I started this thread, it seems that a person could be money ahead just flat replacing panels in 10-12 years based on technology improvements and economies of scale that will continue to drive price down.

Understood. A word of caution: Having been involved is conservation and alternate energy matters for 40+ years, I think I know a few things about these matters. However, I'm mostly unfamiliar with your details or at least nowhere near as informed as I'd be if on site. And, since none of us is as smart as all of us, other's may and probably do have a different take or two on some of what I think, or know some stuff I'm ignorant of. Still, I think my opinions on these matters are based on training and experience. And I try to keep my fingers still unless I feel confident in writing something. Bottom line: Get as many informed opinions as possible from folks with no skin in the game or from those prone to repeating what they hear/read and otherwise ignorant.

As for your question, an opinion: A reasonable place to draw the line is not with the panel source or price, but with the installer. I'd avoid no/never heard of names for panels and other equipment, but most likely so will a reputable installer who has been around for a long time and plans on staying in business. Know this: Vendor quality, professionalism and integrity are about the highest priority if you want a good install. A good vendor can be worth a few bucks extra. A lousy or unprofessional installer can use the best equipment (of which there are many choices) and you'll have a higher probability of a problematic system. On panels, because they are a now pretty much a commodity, buy reputable product, and probably from a mfg. that's likely to be around for awhile. Don't fall for or buy the Sunpower trap for example. Technology will change, but for now, and as an opinion only, I don't see any quantum change in quality or technology on the horizon, nor much of any incentive for R & D to change that situation, particularly with the gutting of NEM. Also,10 years from now a well and professionally installed system will still be producing about 95 % or so of the annual output it started with after accounting for output variability due to weather, pretty much regardless of equipment as long as it's mainstream quality to begin with and professionally installed. As for price, more opinion. Prices will probably continue to drop, but my guess is any further price declines will be less than in the past, with a large part of future price decreases driven more by the decrease in residential PV cost effectiveness as a result of the aforementioned gutting of NEM.

Factoid: Things in CA for new PV customers of the big 3 investor owned utilities have ~ 20-25% less cost effective systems than if the old NEM rules were still in effect. I don't know what's up w/AZ POCOs/policies, but I hear it's not as sweet a deal as in the past in at least some cases. Respectful suggestion: Another reason besides more conservation to look before you leap: Check your POCO's policies relating to residential PV, in your case maybe especially for system size limitations/restrictions.

Good luck.

[bcroe]

Just adding more comments here. I have 2000 Sq ft plus a like sized, partially open basement,
which is is fully maintained at any temp I like. The purpose of solar here was so I could use as
much energy as I like without feeling guilty about fuel use. With 27,000 KWH generated a year,
the house is easily maintained through winters far below zero F, AC in summer is a slam dunk
here in northern IL, and some energy is left over for keeping a shop always above freezing. This
40 year old house is not at all up to latest high efficiency standards, but my appliances are.

With your high efficiency construction, a consumption of 75,000 KwHours a year does beg
investigation. Your first objective should be to spend efforts to itemize just where all those
KwHours are being consumed, which of course is going to vary with seasons. With that
understood, an effective energy plan can be created.

Here the latest heat pumps demonstrate SEER of up to 33, or a COP near 4. Plenty of
currently available equipment cannot approach those figures. If yours ever switch over to
resistance heating in winter, you lose big time. Mine run year around, that would be easy
to do with the latest units in your winters.

Heating water is a very big energy sink. If that is a biggie, look into heat pumps or even
high efficiency propane. I could imagine 2 water heating heat pumps, one pulling heat
from inside in summer temps, and the other pulling outside heat in winter.

Ground mounts are great, I have a list of 45 reasons favoring them over roof mount.
good luck, Bruce Roe

[foo1bar]

So let me set the stage one step further...if I told you that today's "premium" top tier high technology cell phone, laptop or UHD TV today came with a 10 to 25 year product/performance warranty are you likely to keep it and use it for 10 to 25 years?

Yes - I am very likely to keep my TV for 10+ years.
I kept the previous one for 10+ years, and only replaced it when it became quite cheap to replace it, and it offered some benefits beyond what I had. My current TV is ~5 years old and I don't see a reason I'd replace it in the next 5 years.
My cell phone probably won't survive that long - I tend to kill them in much less than 10 years.

If TODAY I buy a ~30Kw solar system with "good" (e.g. REC/Peimar) but not top tier performance panels (LG/Panasonic/Sunpower) that can be had at close to half the price (e.g. REC N-Peak REC320NP 320w Mono Solar Panel for ~$176/panel vs Panasonic VBHN330SA16 330w Mono Solar Panel @ ~$342/panel) the "today's" cost of just panel's is about $15,488 vs. $30,096, close to a $15K price difference!!!

So an REC panel for $0.55/W
Or a Panasonic panel for $1.03/W
I'd probably choose neither and go with Canadian Solar for $.50/W or an LG for $.65/W

But from rest of this thread it looks like you're looking to buy turn-key system, not DIY - so you are going to be more tied to what the installer handles.
And a lot of your system cost is the installation - so more likely the scenario is
$90k for 30kW system with better name brand (possibly more efficient or better warranty etc)
vs.
$80k for 30kW system with lesser name brand.

I'd probably go with the cheaper $/W option.
I wouldn't plan on upgrading the panels in 5 (or 10 or 15) years.
The 30kW system might be producing 20% less in 25 years. But since you have plenty of acreage, it likely would make a lot more sense to add 6kW more of panels in 20 years, rather than replace the existing ones with new. At least my belief is that it's very likely to be a lot cheaper to add a ~6kW array vs. remove and replace 30kW of panels. I'm guesstimating labor to be similar (setting up the racking and mounting new panels vs. removing and replacing a much larger # of panels). And I'm guesstimating that 20-25 years from now the cost of racking and inverter and such for 6kW array is still much less than 24kW of modules.

so am I money ahead just flat out banking the ~ $15K price difference today and in 10-12 years when we see another "significant" step function change in panel cost reduction AND more importantly performance increases..... just flat replace today's "good" panels with "good" new future panels because I absolutely positively guarantee that a relative "good" panel in a decade will make todays "premium" panels look totally inefficient compared to what WILL be available then and enjoy the savings of a "good" system today and a killer system (relative to today) in 10-12 years rather than one which will clearly be mediocre by future standards that just continues to deteriorate and can't perform relative to what will be available?

I'd probably take the savings today.
Or do a larger system for the same price if that's an option.
I don't think replacing panels is something that will make economic sense in 10-12 years - or even in 20 years.

[Bzzy56]

Well, well ,well, I gues there is noi need for an energy audit lol....as many of you suspected we have found the energy enemy!

Long story short, the local Utility Compnay swapped out my Meter Head today (after testing it onsite) for another Brand that they also carry but has more user friendly option for the user. Both meters tested out at between 100.12% to 100.02% accurate so we can rule out any issues with incorrect readings....step one! The Tech showed me how to scroll through the user menu to find instant Kwh usage and before he even connected it I shut off the HW tanks just to see base load for the house.....it registered 0.021 which needs to be multipled by 40 (for my 400 Amp panel) to show ~0.840 Kwh of current usage or roughly 840 watts (see I'm learning J.P.M.!!!). This seems reasonable to me considering we have 5 refers/freezers, various clocks on appliances, computer on, TV's idling, etc.

I then tuned on the HW tanks and BOOM...usage immediately climbed to 0.136 * 40 = 5.44 KWh - 0.840 (for the base load) =4.6Kwh just for the HW tanks coming on!!! Then it was nice that suddenly the 5 ton heat pump kicked on for about 5 minutes and it just happened to drive consumption to a maximum of 0.201 which then equated to an additional 2.6Kwh of load but as I stated earlier within minutes it shut itself off when it cooled the house down 2 degrees. Now obviously the water heaters are not going to be using a continuous 4.6Kwh of load but it is clear that the HW circ pump is driving the need for significant continuous HW usage at times, especially since no one was showering or using hot water during these measurements!

[J.P.M.]

Well, well ,well, I gues there is noi need for an energy audit lol....as many of you suspected we have found the energy enemy!

Long story short, the local Utility Compnay swapped out my Meter Head today (after testing it onsite) for another Brand that they also carry but has more user friendly option for the user. Both meters tested out at between 100.12% to 100.02% accurate so we can rule out any issues with incorrect readings....step one! The Tech showed me how to scroll through the user menu to find instant Kwh usage and before he even connected it I shut off the HW tanks just to see base load for the house.....it registered 0.021 which needs to be multipled by 40 (for my 400 Amp panel) to show ~0.840 Kwh of current usage or roughly 840 watts (see I'm learning J.P.M.!!!). This seems reasonable to me considering we have 5 refers/freezers, various clocks on appliances, computer on, TV's idling, etc.

I then tuned on the HW tanks and BOOM...usage immediately climbed to 0.136 * 40 = 5.44 KWh - 0.840 (for the base load) =4.6Kwh just for the HW tanks coming on!!! Then it was nice that suddenly the 5 ton heat pump kicked on for about 5 minutes and it just happened to drive consumption to a maximum of 0.201 which then equated to an additional 2.6Kwh of load but as I stated earlier within minutes it shut itself off when it cooled the house down 2 degrees. Now obviously the water heaters are not going to be using a continuous 4.6Kwh of load but it is clear that the HW circ pump is driving the need for significant continuous HW usage at times, especially since no one was showering or using hot water during these measurements!

Thank you for the information. I'm pretty sure that instant "KwH usage" (sic) is in kW, not kWh.

Here's the deal. Watts, or kilowatts is a unit of power, the time rate of doing work == 1 N-m/sec = 1 joule/sec. If you have a device that uses 1,000 watts and it stays on for 1 hour, it consumes, and you will be billed for one kilowatt-hour (1kWh) == 3,600 joules/hr., or 1 j/sec. for 3,600 sec.
Kilowatt-hours are units of energy (actually work). To class it up and pay respects to some of the giants who came before us, the abbreviations of units named after such folks are capitalized (hence kWh and not kwh or Kwh). A least that's how I understand the convention is working at this time.

Use that FWIW, or scrap it.

In the meantime, if you want to save energy, ax the recirc. system. Or, shut it off for a few days, read and record the meter reading at the same time every day and see how it goes. If I'm right in my suspicion, you'll see a noticeable reduction in usage. I for one would be interested in the results of such an experiment.

Good luck.

[bcroe]

So let me set the stage one step further...if I told you that today's "premium" top tier high technology cell phone, laptop or UHD TV today came with a 10 to 25 year product/performance warranty are you likely to keep it and use it for 10 to 25 years? Why not? Simple, technology will make it obsolete long before 10-25 years!

Perhaps that is the common feeling, perhaps why there is so much debt. Having spent a career working
on new technology, having seen things a decade or 2 before the public, it does not blow me away. I did
dump my really ancient freezer and quite old fridge, to be replaced by the most energy efficient fridge-freezer
on the market, real payback there. But the color CRT TV (with converter box attached) was only replaced
recently when it blew up after 19 years. My main driver is still a 77 Olds. Things here get replaced when
they can no longer do what is required, not sooner. Bruce Roe

[Bzzy56]

Thank you for the information. I'm pretty sure that instant "KwH usage" (sic) is in kW, not kWh.

Here's the deal. Watts, or kilowatts is a unit of power, the time rate of doing work == 1 N-m/sec = 1 joule/sec. If you have a device that uses 1,000 watts and it stays on for 1 hour, it consumes, and you will be billed for one kilowatt-hour (1kWh) == 3,600 joules/hr., or 1 j/sec. for 3,600 sec.
Kilowatt-hours are units of energy (actually work). To class it up and pay respects to some of the giants who came before us, the abbreviations of units named after such folks are capitalized (hence kWh and not kwh or Kwh). A least that's how I understand the convention is working at this time.

Use that FWIW, or scrap it.

In the meantime, if you want to save energy, ax the recirc. system. Or, shut it off for a few days, read and record the meter reading at the same time every day and see how it goes. If I'm right in my suspicion, you'll see a noticeable reduction in usage. I for one would be interested in the results of such an experiment.

Good luck.

Dang it, busted again but now educated again lol! And yes, I will report back my findings!

[foo1bar]

.....it registered 0.021 which needs to be multipled by 40 (for my 400 Amp panel)

It may (or may not) need to be multiplied by 40.
But it certainly is not because of your 400A main service panel.
A "400A panel" is like saying how big of a pipe you have - it isn't measuring how much water is flowing through.
The POCO use the same meter whether you have a 400A panel or a 200A panel or an old 60A panel. And no matter what size panel it's hooked up to if you have a 4kW hot water heater drawing power it should (and will) give the exact same measurement.

If it were me I'd do something to determine what the right multiplier is - if any. I'd borrow a "kill-a-watt" - your library may have them - the POCO may have them for loaning out. I'd use that to measure something that uses significant power (like a hairdryer, which is often ~1kW) Then I'd check that when I turn on/off the appliance the meter readings go up/down by that amount. (Or determine how much they go up/down by so that I can determine what multiplier is correct)