# Solar Panels per Household in a Perfect World

## How Much Energy Consumption per Household

– Residential customers in the United States (132.58 million) directly consumed 1,378.6 TWh (Terawatt hours) of electricity in 2017.

Source: electricity consumption data is based upon data mined from US DOE Energy Information Administration.

An average residential customer in the United States used 866.55 kWh/month (Kilowatt hours) during 2017.

With the average US residential cost of \$0.1289/kWh the average monthly electrical bill would be \$111.70, prior to additional taxes and fees.

## How Many Solar Panels Required

With that said, I thought it would be fun to figure out how many photovoltaic solar panels it would take to meet that demand.

### Caveats

Note: Before anyone starts with the caveats, I’ll beat you to it…

1. This is not practical in many areas due to climate/geography.

2. I’m not saying that it’s cost effective to implement solar power. It can be expensive – depending on what you’re doing. Though there are ways to keep costs down by implementing smaller systems just for ‘essentials’, offset with tax credits, and other ways. I do like it for preparedness!

3. Number of hours direct sunlight may vary quite dramatically.

4. Seasonal issues affect solar power output (winter vs. summer). Fewer hours of daylight, lower angle of sun in winter. Far worse in the north.

5. Battery storage requirements (and associated equipment costs) if you want power at night or cloudy days for off-grid living.

Okay, like I said, I’m just doing the basic math for fun, for the ‘average’ residential customer consumption – as though it’s a perfect world. Here goes…

### Assumptions:

300 watts per solar panel (typically available these days)
6 hours per day sunlight (use worst case winter hours)
Ability to store the energy (though some grid-tie)

### Calculations:

29 kWh per day electricity consumption (867 kWh / 30 days)
4,800 watts per hour production (29,000 / 6)
16 solar panels (4,800 / 300)

#### A PERFECT WORLD

Okay, now that’s in a perfect world. Never any clouds and guaranteed at least 6 hours/day of sunlight. Typically one would increase # solar panels to accommodate extra for less than ideal conditions. Plus, extra power to store in batteries for “a cloudy day” (or two, or…). Although some people simply grid-tie (no storage for night time or off-grid capacity) where the system automatically switches to grid when it needs to.

#### GOOD INVERTER

Oh, you’ll need a good inverter too. They essentially turn DC (solar panels & battery power) to AC (home electrical power).

#### BATTERY BANK & CHARGE CONTROLLER

Plus, if you want power available at night, you need to store it! That will require a battery bank and charge controller. The batteries store the energy and the charge controller charges the batteries during the day.

Some manufacturers have both built-in to one unit (inverter & charger).

#### EFFICIENCIES

Then you get in to other issues such as inefficiencies of the equipment (though they’ve greatly improved in this area).

They’re a current advertiser here (disclosure) however they wouldn’t be if I didn’t believe in their product.

My current inverter is an Outback VFX3648 for my relatively small system. It seems to be pretty good at efficiency.

#### OFF-GRID BATTERIES

This can get expensive. Typically people have used lead acid batteries for off-grid energy storage.

Today there have been great strides in other battery technologies such as lithium iron. They have their advantages. A big one of which is their storage density. It takes far less battery space and weight to store energy in lithium batteries than lead acid! They can also be greatly discharged each cycle without damage like would happen to lead acid batteries.

A company well regarded in the industry is Iron Edison. Again disclosure, they’re an advertiser with us. However their products are well worth considering when it comes to off-grid system design.

Continue reading: Lithium Iron Battery For Solar Off-Grid Systems

Bob’s Alternative Energy Category Page
Don’t forget to also check out what Bob has over at ReadyMadeResources in this category of alternative energy. It’s fun to browse and see what’s out there.

### CONCLUSION

Well the only real conclusion is that in a perfect world, it would take about (16) 300-watt solar panels per average household to provide enough electricity to feed that average household – according to energy consumption statistics.

Of course some homes consume MUCH more than that and there are LOTS of other caveats to consider.

That said, I simply thought it was an interesting exercise.

### COST

Oh! by the way, given that it costs (about) \$1 per watt for solar panels (more or less), the outlay just for the panels would be about \$4,800. Not counting extra for overhead, other equipment needed and installation costs. So if the average electric bill is say, \$150, that would be an equivalent of 32 months ‘break even’ (for the panels). Though in reality a system costs more than that (not the scope of this article).

Read more: The Four Essentials of Off Grid Solar

Off-Grid Charging System For AA-AAA Batteries, Plus USB

1. Druff says:

So if we just covered the entire state of California, AND all of Washington, D.C. in Solar panels, we could provide the whole country with power!

2. Minerjim says:

Ken,
Thanks for the article, it confirmed my calculations for what we would need here on the farm in Western Colorado. I have noted that panels can be had here for less than \$1 a watt, but like you said the additional equipment required will push your installation costs up. For now I will stay on the grid, but still looking to change over, at least partly, in the future. (I do a lot of welding which will require a bigger genset or our connection to the grid).
I want to bring up another point about ‘everyone’ being on solar. I question on how fast that could happen, if at all. Right now it is my understanding that many of the solar panels rely on ‘rare earth’ minerals for fabrication. China now supplies 95% of those to the world market. We had one rare earth mine in the US that used to supply these minerals. It is presently closed. There are other minor and undiscovered rare earth deposits around the world I am sure. Development time for a mine can be up to a decade. To bring on full scale ‘green New Deal’ production in this country, we would have to find a secure source of raw materials. China is not it. The USA used to maintain a “Strategic Materials Supply”, which included rare earths, but no longer. Seems the politicians did not like the cost of upkeep. Rare earth materials are only going to get used up. Only chance we have would be if new research comes up with solar panels made of more commonly available raw materials.

3. Anonymous says:

I use the water pressure in the city main to power all my generators for free.

4. Anonymous says:

Did you know a waterwheel, running off a garden hose, will produce enough electrical power for all your needs? What’s more, people have NO IDEA the beautiful garden with its picturesque 8′ waterwheel is powering the house, charging the battery bank, and pumping the water which runs it. Do you have seasonal streams? A spillway? Do you live in a place where your water is not metered? Does you water come from an elevated storage tank? How much are you paying for water per acre foot? Would you like to have a fish pond with a lovely overshot waterwheel, attached to an ancient looking mill shed…which is actually where the waterwheel’s torque is turned into electricity, and where the battery bank lives? Want to raise Tilapia in the same pond? Want to use the pond for nearby water storage in huge quantities? Want to avoid the look of a solar farm, which can be destroyed by lightening, wind, fire, and simple vandalism? Think about these things.

1. Minerjim says:

anonymous,
might want to move this over to the weekend discussion. This article was on solar. we try and help Ken by keeping it on topic.

2. Texas Boy says:

To Anonymous;
You said ” A water wheel and a water hose could electrically power a
house”. I now understand why you failed out of engineering college, you have no concept of watts, horse power, system power losses, or system design. Do not try to confuse the folks on this Webb site, they are not stupid, except perhaps for one Anonymous soul.

5. NRP says:

I have greatly considered the Solar Power option.
And as of yet have not taken the \$13,000-\$18,000 plunge.
I do live in a place whereas Solar is ideal, 300 days of sun a year, right Latitude, perfect temps and all the rest.
One may also remember there is a 30% Tax Credit for instillation of Solar for their home.
I also have considered the piece by piece approach of going Grid Tied first (Remember to check that your local Electrical Co. will do a “Buy Back” on power), then moving into the Storage aspect, that would help the initial cost, but would lose a lot of the Tax Credit.
I do know there are a LOT of companies that will finance Solar, plus one can simply get a Home Improvement Loan.
Again getting off my azz is the point. Of course there are laws being passed all the time forcing people to install Solar on ‘New Homes’, thinking California here, at an added cost of \$12-15K per home.
PS; don’t forget the cost of ATF switches if Grid Tied, not a good idea to energize the Grid if it goes down.

6. me says:

Amen on the most Americans use way more power than is necessary for a good life. We did just fine with two 150 watt panels on our boat. We were not running air-conditioning or a freezer but we were running fans and a small fridge, listening to the stereo, watching a VCR tape most nights and using small incandescent lights to read by at night. almost forgot, ran a water maker 2 to 3 hours a day to change salt water into fresh. I imagine we could do it on a lot less now a days with the advances in electronic technology. DVDs versus VCRs, LED bulbs versus incandescent.

The down side of a good sized solar array will be that it will be a target for the powers that be. They will be attempting to maintain infrastructure with no power and it will be difficult. LEOs might be able to patrol on bikes but if there is no way to charge their radios they will be much less effective. Hospitals all have diesel gen sets and enough fuel for three days. Those aren’t enough to meet 100% of their needs, just the essentials. A city government trying to keep essential services could very well decide that they need a new ordinance that will require you to donate your panels.

For those of you have not heard yet Venezuela’s electric grid is currently down. Maduro is blaming it on the US and accusing us of a cyber attack on it. Others are saying home grown sabotage.

For me, I won’t have the capacity to run freezers but I do have a small panel that folds up and can be used to provide for LED lighting and charging for my laptop. Don’t forget that a fixed solar array is easily visible to overhead photography. My panel can be easily moved to different locations and only unfolded as needed.

7. Matt in Oklahoma says:

So looking at 5yrs or more to meet the cost.
How long do those kind of batteries last?
How long do the inverters last?
Realistic panel life is?

1. Papa Smurf says:

– Batteries (Lead-acid) in this use, 5-10 years, but could last 20; inverters, 10-20 years unless mishandled, potentially as much as 50 or 60. The panels themselves start to degrade at around 25 years, but many have been in use in orbital space (less protected) for over half-a-century. They could still be producing at as much as 80% at 100.
– Papa S.

2. @Matt,

How long do those kind of batteries last?
That’s too difficult to answer in a comment thread (well worth another article though). It depends on TYPE of battery, depth of daily discharge, and other factors. It’s easy to damage batteries too (got to be sure the charger is set right for your batteries). Life could be 5-7 years for ordinary lead acid (maybe more, maybe less, depending on DOD and other factors), or even much longer than a decade for some of these newer type batteries. Iron Edison has two types – Nickel Iron and Lithium Iron which last a LONG time. Though expensive up front. But that’s just the way it is. I did a cost analysis in one of my articles…

How long do the inverters last?
Perhaps (almost) ‘forever’ if treated right, adequately protected from spikes/lightning. Capacitors do dry out though after many years. My Outback has been in service for 10+ years.

Realistic panel life is?
My solar panels are from solarworld-usa. They are product warranted for 20 years and have an incredible linear performance guarantee of 25 years. They say the effective output will decline annually by no more than 0.7% for a period of 24 years, so that as of the end of the 25th year after purchase, an actual output of at least 80.2% of effective output will be achieved. That’s good!

Note: Some panels are junk. It will require due diligence.

8. Papa Smurf says:

– Currently in my Faraday cage I have a 40-watt monocrystalline which should produce about 200 usable watts per day. It won’t run a freezer, but it will allow at least limited use of some appliances in conjunction with my 1500-watt inverter, FWIW. I can even put it inside, in the light from a window, to keep my two marine batteries charged up that will give me 2, 200-amp batteries to supply some use of small electronics. I have also two 150-watt, a 400-watt, and an 800-watt inverter, at least a couple of which are usually in the Faraday cage as well.
– Papa

1. Papa Smurf says:

– Mistyped; the two batteries, which are linked together, will produce 200 amps. Each battery is 105 amps by itself. If you use down to 60% of capacity, there’s close to 100 amps available per day. You can get a little above what is available from the battery from using the panel in the sunlight, but it will depend on the amount of light available.
– Papa S.

9. Minerjim says:

OH,
Thanks for your input on this. Your approach and experience shows you did your homework on homebrew power well. Diesel gensets run on canola are sustainable long term, and are robust, less vulnerable to EMP. Solar panels for emergency backup ( freezers/communications). Makes perfect sense. Storing the energy, solar or otherwise, is always the big kicker. I was hoping the ‘salt water’ batteries (Aquion) would come back into production, they showed some promise. Time will tell on them, if they come back. Time for a shot of elderberry “medicine”, and then dinner.

10. Papa Smurf says:

– As OH noted above diesel is better suited in the long run. Solar is really better to use as a “stealth” power source as it makes no noise, and can be concealed pretty easily.
– Papa S.

1. Minerjim says:

Papa Smurf,
Have you ever tried using a ‘buck-boost’ module to get more out of your battery sets??? It would allow you to produce say 24volts from a battery that is dropping in voltage down to say 8 volts. Do not know if your batteries would like this, or if they would be damaged. I have picked up one of these units and plan to incorporate it with some 18 volt NiCad batteries to “buck” the voltage down to 13.8 volts for a small ham radio. When the batteries get below 13.8 volts, it will keep drawing power and ‘boost’ it to the 13.8 volts. Lowest it will convert up is from 5 volts. I do not know what drawing the NiCad batteries down this low will do in the long run. Lead acid batteries would likely be damaged?

1. Papa Smurf says:

– Mine are Marine type lead-acid, the kind for starting/running large diesels. Basically, I got good used batteries for very little money (Core Charge costs). They have held up well and produce rated amount of power at five years age. I have avoided abusing them as best I can. I can provide some LED Lights, Sat TV, Internet Modem, and a fan in the living room for a couple of days w/o any great amount of problem except a looong extension cord and multiple taps. Since it is 12 volt, I can even jump my bank from the truck or jump the truck w/ it. Really, I have been pretty happy with what I have.
– Papa

2. Papa Smurf says:

– Agree that the diesel is quiet, (that’s a steal on the 1.5!) and should probably be the primary power source. On the small Solar, I can set the whole thing in the corner of the living room with the panel on the floor near or hanging in the window. Loudest thing is the cooling fan on the inverter. The dog can sleep right by it. It’s just not the optimum choice, but it is a choice. Personally, when I can manage it, I would love to get one like your 5kw here at Smurf Central.

As a thought, try getting an alternator from an old GM make ambulance or police cruiser.

– Papa

1. Papa Smurf says:

– I’d love to have one, right now, just need the money to pay for it! LOLOL
Unfortunately, my lettuce garden seems not to be producing. Little boys, Doctor bills, etc. Will definitely keep the source in mind though for when it picks back up!
– Papa

2. Papa Smurf says:

– OH,
Appreciate the offer, but for what my truck uses in gas from west Texas, I could have three of four of the things. Considering that this is an article on solar panels, I should probably mention that one of the best sources for used, good panels is those same wrecked or otherwise damaged highway signs. Generally, an inexpensive volt-ohm meter is the only instrument needed other than the Mk 1 basic eyeball to evaluate the things, they are pretty tough.

There are several gen-sets sitting around here nearby, including some that I could probably pick up for similar prices.
I haven’t been in a big rush for one, as I do have a 7.5Kw gas genny from a big-box store sitting in the garage. It really hasn’t been used much, but is available for the while it would last. The diesel just has a much longer duty cycle/life expectancy when it is needed.
– Papa

11. Defcon says:

Venezuela wishes they had more of these. They have been without power for 2 days now.

12. Matt in Oklahoma says:

Thanks for the answers and discussion on this. I was trying to post a thank you but for some reason I couldn’t in the reply sections

13. Plainsmedic says:

Solar panels,
I started with one 205 watt panel. Bought a charge controller and wired it all up with an inverter. Later added another 210 watt panel and then another 205 watt panel. I’ve changed charge controllers and inverters several times. I keep the spares in faraday. Made a few minor mistakes along the way. Nothing dangerous, just would have done things differently if I could start over.

I ended up with two separate systems, both 12 vdc. I have several 100 watt panels on one system with 2 small (400 watt) wind turbines. All of it is off grid. If you pay attention to your battery levels, you can make it work. Mostly I try to run a large chest freezer and a large fridge. If conditions are perfect, I can maintain both. Conditions are rarely perfect.

If I was starting from scratch and \$\$ was a concern, and when isn’t it? I would stick with common sized panels. 100 watt panels seem to be everywhere now. You could always add panels as \$ allows. Spend the \$ for a good pure sine inverter. Wire is a big \$ expenditure for wind turbines. Takes big wire for long runs of dc.

Batteries,
Started with lead acid golf cart style batteries. Ya hafta wire them in series and parallel to get the 12vdc you are looking for. I switched to nickel iron for a while. Very expensive and NOT what they claim. I’m now back to lead acid for both off-grid systems.

I would go with at least a 24vdc if not 48vdc if starting from scratch. I built my small systems myself, when \$ was available. I enjoy messing with the two systems. The turbines help a lot in the winter. There is nothing between me and the north pole. To the south, there are trees and other obstructions, so it cuts into the available summer winds. They still produce some, but not like a north wind.

Solar or wind is an expensive way to produce electricity. It does work, and that is very important to remember. I’ve played around with woodgas too. It works as well. It’s just a very dirty fuel. Takes a tremendous amount of filtering, to make it a viable option. I’d love to play with hydro-electric. They have many options for endless power, if ya happen to have running water near you.

If I was starting over, I’d buy dc appliances (fridge and freezer) and use dc lights. I’m trying to get there, just not yet. Keep your system(s) off grid. You’ll have to buy batteries, but no one can tax you or challenge your right to harvest power.

Use the power, rather than trying to store it. There is a lot of loss in trying to store it. Depending on the status of my battery banks, I switch back to the grid, before going to bed. That is the large chest freezer and the large kitchen fridge. In the morning, I switch back to solar/wind.

I have run separate outlets for the fridge and freezer, so it is just a matter of plugging and unplugging to make the change. I can do both, in less than a minute. Will the batteries handle an overnight with these appliances? Yes, probably, but bear in mind, I’m using the power I’m producing. I couldn’t do it day after day, unless things were perfect.

If shtf, would I have all the power I would need? No. I rather imagine, I would keep the chest freezer going 24/7. Maybe use ice or a smaller fridge to be more efficient. Ice, after all, is just another form of battery.

Any amount of power, you can produce on your own, is great. Air conditioning would be a thing of the past. I like solar. I like wind power, just not as good as solar. Woodgas would be part of the solution as well. I enjoy messing with all these things. My wife is convinced, I’m a wierdo.

14. CrowBait says:

Plainsmedic…..

Like your attitude. LOL If you get a bug in your…..ear……about lighting and your solar power source, try DMASLED dot us. They have a decent inventory. Lots of things to ‘play’ with. Individual modules, strips, dimmers, about anything you’d need for a lighting project. I’m not a dealer, just a user. Don’t make a dime off of sending someone to their site. (Dang it) They have LED strips from 2700 Kelvin to UV and IR, individual modules, floods/spots, wall-washers…..all kinds of stuff. The projects they cause will keep you off the streets and out of most of the bars.

So the shtf and you are on solar. Great, you have electric, until something goes wrong, and something always goes wrong. Where are you going to find the parts to replace something that has gone out. You can’t have spares of everything you need?

1. Matt in Oklahoma says:

I’M NOT SAYING BREAK THE LAW
but if it’s really the end as we know it then the solar flashing stop or speed signs, solar bridge information relays, highway trailer signs, flasher batteries on roadblock signs etc will be harvestable if your out and about.
It ain’t gonna run a freezer but might charge a drill and save your wrist building a new structure or give you a light to cook by in the winter.

1. Plainsmedic says:

Matt,
Agreed. I notice solar panels. There are numerous ones around, that power lights and other things. I could see a time where your “harvesting” could be a viable solution.

You seem to be seeking knowledge about solar. May I suggest something? Buy a small kit system. Harbor freight or Northern tools, among many others, sell kits. They have everything you’ll need for experimenting. Do it now, before the need arises. I found it to be a fun learning experience.

You’ll soon discover, just how much solar power it takes, to actually power appliances or tools. I was shocked (pun intended) to learn how many watts it would take. I’m a hands on type learner. I have to touch things and hook them up. Start small and build from there.

I still have an old HF kit that works. Not currently in operation, as ya kinda need to match the size of panels in your system. In shtf, the HF kit would quickly be placed in action. We’ll need all the power we can harvest.

1. Matt in Oklahoma says:

Yeah man that’s in the plans. Solar isn’t my strong suit so yeah I’m absorbing it in. I had touched on it many years ago but things have changed since then. Things are lasting much longer. Panels used to only be good for 5 years at tops

2. Papa Smurf says:

– Matt, the HF panels are the poster child for the “5 year panels”. Try to get some name brand panels , at least a couple, and be prepared for a much longer service life.
– Papa S.

3. Papa Smurf says:

– BTW, Northern Tools carry very good ones. The “harvest-able” ones mentioned also tend to be top quality, too. And yeah, I notice them, too.
– Papa

2. Plainsmedic says:

Your comment is very true. Why can produce from your garden? You will just eat it and then it’s gone. Yea, I know. Grow some more food, next year. Same thing with solar. If you figure out how it works, there are numerous things you can do. For example; Use dc lights and appliances. That means no inverter needed. If you own a multi-meter and are willing to keep tabs on the battery’s charge, you don’t even have to have a charge controller.

The panels themselves, have little to go wrong. Salvage the tail lights from an old defunct car and wire it up to a battery. You have light. It’s not the answer for everything, but it could make your life easier. I’m sure you have knowledge and skills about many things. You could/can do this too. I’m rooting for ya!

16. Papa Smurf says:

– As Plainsmedic noted, wind and solar are both expensive means of generating power. If it makes it a bit more palatable, just imagine that you are buying a generator and prepaying for the fuel that you will use. The 40-watt I bought that is currently in my Faraday cage was the next step up after playing with a 5-watt car/truck battery charger, which is still useful (and used), and even the little solar yard lights make a useful amount of light. They have fractional watt Panels on top of them, too. A bouquet of half-a-dozen will change a blacked-out house from scary to merely shadowy, and a 6-year-old can manage them if shown what to do.
– Papa S.

1. Papa Smurf says:

– And the yard lights will recharge one or two AA batteries, depending on the model, and just require that you harvest the charged batteries and replace them with discharged ones. Far and away the cheapest means of utilizing solar at least a little bit.
– Papa

17. JJMNAV says:

I had a quote on a couple Grid-Tie systems to be installed and at this time did not make financial sense. At my average electric bill of \$100 per month with tax credits applied:
\$20,300 7250 Watt system would take 16.9 years to break even. \$12,180 4425 Watt system would take 10.2 years. And that assumes \$0 failure/repair/maintenance costs.
Online research indicates that with the \$12,180 investment I could install the 4000+ Watt system as an Off-Grid system with battery bank. Meanwhile, I will just keep my 80 watt Harbor Freight system on standby for short grid down assist.
Where I am – wind power is marginal BUT when days are cloudy most often the wind speed picks up so considering a hybrid system.

1. @JJMNAV, It certainly is not cheap. And you’re right – payback (break even) is often many years down the road. There are lots of variables and factors that may affect the overall cost of a system.

From a preparedness standpoint, it does bring peace of mind. But everyone has their own unique budget and threshold for preparedness sake.