August 13, 2019

Solar Pantry Part 1: Feasibility

One of our goals for 2019 is solar back-up for the refrigerator and freezer in my pantry. If we ever lost power for more than several days, I'd have to scramble to save what I could and lose the rest. In summer, a lengthy power outage would likely be due to hurricane damage or an intense lightning storm. In winter it would be from an ice storm. So far, we haven't lost power for long enough to worry about food stored in these appliances, but these scenarios are very real possibilities.

I got the idea for a solar pantry from a book I reviewed awhile back, Prepper's Total Grid Failure Handbook. (An excellent book; you can read my review here.) The authors bring solar energy down to a small-scale, realistic level for someone like me. My thinking has been that if I can at least have solar energy for my fridge and freezer, I won't have to worry about losing the food I have stored in them.

My first step was to measure how much electricity these appliances use. From that I would be able to calculate how many solar panels I'd need and how big to make my battery bank. To find that information I used a Kill-A-Watt meter.

Recording watts used by my 400-watt food dehydrator.
Obviously it's a good idea to check wattage for yourself

Recording kilowatt hours.

I measured each appliance separately and added them together. From that I learned:
  • Refrigerator uses 2.6 kilowatt hours per day
  • Freezer uses 1.6 kWh / day
  • Total for both appliances is 4.2 kWh / day

Well, compared to my monthly electrical usage that didn't sound too bad. Then I started running the numbers.

We already have the solar panels. I found them on Craigslist about the time I reviewed Prepper's Total Grid Failure Handbook. They were leftover from a larger job, and we were able to get several new 345-watt Sunpower brand panels for $240 each. What I needed to know was how many panels I'd need and how to size a battery bank for several days of no sun. For that, I looked for an online calculator.

There are a number of online calculators for this, but I found that most of them are developed by businesses geared toward the brands and services they sell. They may give results as packages they offer, or want you to contact them to get the results. Wholesale Solar has one that I thought quite straightforward to use and gave me a ballpark estimate online. The most helpful step-by-step guide was at Preparedness Advice blog. I used both and my results from each were similar. However, what I discovered was quite dismaying.

Assuming I receive at least five hours of sunlight daily, here's what I'd need to make and store enough energy for three days of cloudy day use:
  • 1.32 kilowatt size system
  • 4, 345 watt solar panels
  • 11, 200 amp-hour 12-volt batteries
  • Or 8, 260 AH 12-volt batteries.

[NOTE: Batteries used for solar battery banks are deep cycle batteries, not cranking (starting) batteries. Deep cycle batteries are measured in amp hours (AH). This doesn't refer to actual time, because performance varies with conditions (such as temperature). Rather, AH is a way to compare the relative storage capacity of deep cycle batteries. The greater the amp hours, the longer they last before needing recharging.]

Back to my results. Discouraging because I would need more batteries than I assumed! Considering that 200 AH deep cycle batteries start at $350 for the cheaper ones (and 260 AH start at about $500), I have a budget problem. I only have $1500 for this project, and besides batteries I still need to get a charge controller and an inverter, plus all the miscellaneous items like racks, wiring, etc.

The pantry refrigerator, however, is an old one. Out of curiosity, I ran the numbers again with an Energy Star fridge. The following is based on the advertised energy rating and not my actual usage, which of course, could vary. I used an average estimate for low-end energy efficient refrigerators, and here's how the numbers changed:
  • Energy★ fridge 0.94 kWh / day (Quite a significant drop!)
  • Same freezer, 1.6 kWh / day
  • Total for both appliances is roughly 2.6 kWh / day
Total usage for both is the same as my current fridge uses in one day!

For three day's electricity storage with that fridge I'd need:
  • 0.8 kilowatt size system
  • 3, 345 watt solar panels
  • 7, 200 AH 12-volt batteries
  • Or 5, 260 AH 12-volt batteries. 

As you can see, energy efficient appliances make a big difference! The cost of such a low-end fridge is about the same as a 260 AH battery, so if I had a bigger budget I could buy a new fridge and still save over $1500 on the batteries. But the budget is what it is, so at this point, feasibility is near impossible. However, that doesn't mean that the mental wheels stop turning. More on that in Solar Pantry Part 2: Analysis.


LaFe said...

Hello :)
It's a lot of time that I have the pleasure to read your blog, one of the most useful around the net.
I really admire you, your work and I think you have great managment skills.
Interesting this post about solar panels, a question: do you think they are really useful? or it's just too much (in term of quantity and usage) what we have nowadays to be supported by a system totally sustainable?
have a nice day :)

Leigh said...

Hello Federica and welcome! Thank you for your kind words and for taking the time to comment. You ask good questions. I do think solar energy can be useful, but I think it has limitations. One is that it can't sustain the modern lifestyle that most people want. For solar power to be realistic, people would need to drastically decrease the amount of energy they use. For individuals that wouldn't be too hard, but for mass manufacturing it would be near impossible. The other thing is that while energy from the sun is sustainable, the equipment to harness it is not. It all has to be manufactured and it all has a service life. Eventually, all parts of the system must be replaced and the old parts discarded. So whether or not it's really useful is an individual decision. In my next couple of blog posts in this series, I'm going to look at possible alternatives for my goal.

Sam I Am...... said...

This is very interesting since we had that ice storm several years back and I was without power for over a week. Good luck~

imsovintage said...

Hi, I really love your blog because the info is always so useful! I live in a small city and I'm somewhat disabled but I find there are so many ways I can use your info. I would love to live as you do but that is no longer feasible for me.

I think about solar possiblities quite a bit but there are a lot of complications if you don't have someone to sustain it. Which I don't. But I have thought about a whole house generator that runs on propane. Have you ever considered one of those? Do you think they are a good alternative?

Many thanks!


Glen Filthie said...

Leigh, solar only makes sense in two circumstances - maybe three:

1. There is no other source of power available
2. You’re a hobbyist that enjoys tinkering with alternative energy technologies
3. The gubbimint in your area offers subsidy programs to offset the costs of ownership and installation.

To be brutally honest you would be far better served by a good large diesel generator than solar. Other considerations:

- if you have any issues with shading you will want optimizers to maximize your energy harvest. Anyone can slap together a system and it will make electricity. Putting a system together that will work in a crisis, that will provide serious, usable amounts of power... you will want a reputable solar professional to design the system to make sure it complies with local electrical and building codes. They can tell you why it makes sense to use MPPT charge controllers vs PWM ones, for example. A serious installation will run you anywhere from 15,000.00 and up. Such an installation is no job for Bubba The Shadetree Electrician, or even a moderately competent one. Reputable Red Seal electricians will take special training before working with solar.

- most panel efficiencies degrade at one percent per year. Or more. In 20 years your array will probably be producing about 80% of what it does when new. Most of the inverters and optimizers are made in China and have warranties good for ten years.

Solar is cool and fun... but if you are serious about being prepped... unfortunately the generator is still the best way to go.

Flynn said...

Hi, I love your blog. I think we are near-ish you in Southern appalachia, so similar solar conditions and we recently installed solar this spring (4kW panels and eight 220 Ah batteries). We love that now when the power goes out (frequently!) we barely notice! 4 kWh per day for 2 appliances seems *really* high, especially as once they are cold, they should only be running occasionally to maintain temperature. Maybe energy efficient appliances do make the difference, but I might try replacing the seals on the fridge and freezer and see if you get any improvement.

J.L. Murphey said...

We've got the panels, inverter, and charge controller all we're missing is the batteries for total energy consumption. Check Harbor Freight for inverter and charge controller. They are the cheapest I've found. I didn't want a second hand of these. We are budgeting for the batteries and a propane generator. The propane generator is for backup for week long rainy days. We still need to cut about 20 trees too.

If we'd had the batteries we wouldn't have lost a freezer full of meat earlier this summer with no power.

Leigh said...

Sam, inconvenient, isn't it? It's always good to have a back up plan, although most people aren't trying to store as much food as we are and likely won't have as big a problem.

Jan, thank you! The whole solar thing is a learning curve for us, including learning how to maintain it. Some of it depends on the kind of charge controller one gets, also on the kind of batteries. I have some small ones (by that I mean 35 AH) that are sealed and so no maintenance. As far as generators, my husband is a fan. We don't have one, but it's on the wish list. With that, you are still looking at a battery bank for the generator to charge, unless you want to leave it running all the time. Do the math. Figure out how long the generator can run on a full tank, and how long you plan to run it. That will give you an idea of economic feasibility. One good thing about propane is that it doesn't have a shelf life like gasoline and kerosene do.

Glen, lots of excellent information in your comment. And as always, with a wonderful twist of humor. :) We have considered much of it, including cost and life expectancy of the parts. Any sort of subsidy is out, but then, we aren't looking at whole house, only two appliances. I'd say we fall more into your hobbyist category, but with a serious goal in terms of food storage. Dan would definitely agree with you on the generator, but he's interested in some small solar projects as well.

Flynn, that 4 kWh is indeed quite high. Part of it is the old fridge for sure, and I think part of it is because they have to work harder because the room is so warm (mid-80s in summer, usually). That doesn't help. That's a very good idea about replacing the seals. The difference in swapping the old fridge out for a theoretical energy efficient one is amazing! When I measured the readings I saw the power surge when the appliances were first plugged in, but there's no reset button to cancel that out. Still, it gives me some numbers to start with.

Jo, what a shame about losing all that meat. That's exactly the reason I'm motivated to get some sort of alternative in place! Thanks for the source. When we get to that stage I'll take a look for sure. Dan wants a generator for back up as well, but like you, it's all in budgeting to save up for everything.

Chris said...

I like the idea of digging a pipe underground, and bringing it up through your pantry. It brings cold air from underground, and drops the temperatuere inside the food storage area. I think it's called a cool cupboard. I don't believe it gets cold enough for refrigerated items, but at least you could save any fruit/vegetables/nuts, etc, stored in the fridge. I wonder how it would work with cheese storage too?

It's a pretty straight-forward design, so long as you can get an implement to dig under the house, to fit a pipe. If I had a house on stumps/stilts, I would build a cool cupboard. It would probably be excellent for storing rice/grain/beans (long term) too.

Su Ba said...

As you know, hubby and I are off grid and use solar as our source of electricity. It takes a bit of time and dedication to learn to function successfully with a solar system. And such a system isn't ideal for most situations. In your case, personally I'd opt for a generator instead of solar. It would be far cheaper! And easier to use and maintain, far less of a learning curve, and you'd be less apt to mess it up. Keep in mind that newcomers to solar frequently ruin their first battery bank rather quickly during the learning curve. We killed our first set of batteries in two or three years even though we tried hard not to. Something to keep in mind. Also, even when you're not using the system, you still need to maintain the batteries correctly. Otherwise you will kill them without even having had the opportunity to benefit from them.

If you do opt to try solar, look into golf cart batteries. They are far cheaper to create the battery bank than solar system designed deep cycle batteries. Especially for your first battery bank, it will hurt less when you kill them. We started out with L-16s.....ouch when we killed them! Replaced them with L-16s. But after that we went with golf cart batteries we purchase from Costco. Much cheaper and lighter to handle. Batteries can be very, very heavy. We have had very good success with the Costco batteries.

As for a generator, we use a Champion bi-fuel (uses either gasoline or propane) we buy from Costco. It has an electric start which we very much appreciate. We change our generator every time we change the battery bank-- every 6 years or so, but we use our generator on a regular basis to tup up the batteries as needed. Plus use it when operating heavy loads, like the clothes washer or construction tools. Building things around this farm means I frequently use construction equipment. So it gets a lot of use. Over time & use the electrical output diminishes with generators, thus the reason we replace them, giving the old one away to someone who can't afford to buy a generator. An old generator is better than no generator. Old generators tend to take longer and longer time-wise to charge the battery bank.

I'd also like to comment about Chris' idea. If you opt for the underground pipe idea, keep in mind that mold can be a serious issue. People in my area have tried them but didn't have a means of dealing with the condensation that forms in the pipe and the resulting mold. You would think that the water would simply drain out and that would be that, but in reality it doesn't happen that way. Then there is always the issue with bugs and rodents. Got to do something to keep them out,

Leigh said...

Chris, I call the buried pipe "Arabian air conditioning" because it's ancient middle eastern desert technology! From what I understand it works best with dry climates, which is why we never seriously considered it. As Su Ba mentions, with humidity comes problems with mold and mildew, which is a constant battle for us. Another idea is a crawlspace to attic shaft in the interior of the house, with wire shelves to keep food items. Is that what you mean by a cool cupboard? Where cool air is drawn up from the crawlspace to help keep food cool. But that's another idea better suited to dry climates, but it's one we discuss from time to time. I'll share all my research on alternatives in part 3.

Su Ba, 6V golf cart batteries are exactly what the authors of Prepper's Total Grid Failure Handbook recommend, so those are the first batteries I researched and planned to buy. It's true, they are much, much cheaper. But I'd need more! I didn't include it in this blog post, but I calculated that for the 4224 amp hours I'd need for my current appliances, I'd need 19, 230 AH 6-volt batteries(!) I can get these locally (so no shipping) for about $155 each (before tax but including core charge) so that's almost $3000 which is still outside my budget. We don't have a Costco, so those are from Batteries + Bulbs, and is the best price I could find.

Dan's a generator guy although we aren't at a point where it's seriously feasible to get one. You point out something that I'm always interjecting, that it too, like all equipment will wear our and eventually need replacing. My personal preference is always toward figuring out ways using the lowest tech possible. More on that in the next couple of blog posts.

Kelly said...

We're currently in the process of going solar for our entire home, so I find this interesting. We're not opting to go off grid, but should eliminate all our usage charges with the power company. After years of using a welding unit to run our major appliances/lights during extensive outages, we're finally putting in a generator that will kick on (and back off) automatically. As much as I always appreciate having the welder when needed, it is a pain to hook up and keep running with gasoline.

I'll have to watch Ed's sidebar for your updates!

Leigh said...

Kelly, so you're going for a grid-tied system? Have you blogged about it? I'd be very interested in it. Dan and I will never get to whole house solar, either off or tied, but it interests me just the same.

Renee Nefe said...

A lot of my neighbors have solar. One claims that her electric bills are only $12 per month. I find that very hard to believe...especially in a very hot summer like we are having now...perhaps in winter when she is running mostly gas.
On the Air Force Base they installed Solar on a building and Geothermal for another. I believe that they lost the solar panels in the first hail storm we got. In the end after 5 years it was concluded that neither solar or geothermal were feasible in our area.
We frequently get solar sales folk at our door, but hubby tells them no...not interested in their speech.

Anonymous said...

Have you thought about RV/Marine (DC) appliances? The reduced panel array and battery bank necessary for DC, and skipping the inverter, could help offset the cost of buying new appliances, especially if you could find some used or at the junkyard

Leigh said...

Renee, you do get an awful lot of hail, so I can see why panels wouldn't necessarily be a good idea. Interesting about the geothermal. When I researched it many years ago I learned that a backup heating system was still necessary. We thought, then what's the point? Especially considering how expensive they are!

Unknown, yes I did look into DC appliances. I agree it would be more efficient to skip the inverter. I learned that a DC fridge to replace the one I'm discussing would cost about $1500. So that was the end of that! Still, I should keep my eye out for a used one. You never know.

Su Ba said...

Frig 300 freez 800

We have dc frig and freezer. In our climate the frig uses 200 watts per day and the freezer uses 800 watts per day. They are both chest type Sundanzers. We operate them with four 100 watt solar panels. The battery bank consists of four Costco 6 volt golf cart batteries. The charge controller was an inexpensive one. No inverter needed. The panels are mounted on a homemade frame made from aluminum angle, which is easy to cut and drill. The wiring to and from the batteries was standard wire purchased at Ace Hardware. I don't know off hand the gauge, but I could ask hubby if you need to know. The pricy wire is the cables that connect the batteries, but since there are only four batteries, it wasn't all that bad financially. For a ground we had to run 20 foot of solid copper (again, I'm sure of the gauge) buried about a foot underground, since it's impossible to go deeper. I keep the ground area moist by channeling rainwater to it, and hand watering if there is a drought. We have seldom had to tup up the batteries. We get about 3-5 hours good sun a day. But after 5 days of zero sun hubby gets nervous and attaches the battery charger to them. Without an expensive inverter, we can't use a generator to charge them. It's both simpler and cheaper to use a standard battery charger plugged into the house current.

The dc frig & freezer were expensive to initially buy. $1600 a piece. They are most likely cheaper on the mainland. Buying them meant we needed a lot less of a solar system, thus a lot less expense. Just think....4 batteries vs 20 batteries. The savings there alone pays for a new Sundanzer. And you don't need to buy an inverter. Nor the extra solar panels. Nor all those extra battery cables. Oh by the way, battery banks use an even number of batteries since most small solar systems are 12 or 24 volts, depending upon how far a distance you need to drive the current. That odd extra 6 volt battery wouldn't fit in.

Chest freezers are common enough, so it's not a big deal to get use to a Sundanzer freezer. But the chest frig is something most people have never dealt with. Not being self defrosters, they have condensation issues. But there is a built in drain plug that a hose can be attached to, thus automatically draining excess moisture away. One thing a chest frig has trained me to do is not fill up the frig with needless junk that never gets eaten. All those multiple bottles of salad dressing, sauces, pickles, leftovers, drinks that just sit there until they go bad. Eliminating the clutter makes having a chest frig a better experience.

Kelly said...

We did consider going off grid with something like a Tesla powerwall, but ended up ruling that out so yes, we'll still be tied to the grid. If all goes as planned, our only utility cost each month will be the unavoidable base charges. Solar is something we've researched for years and it finally reached the point that all the planets were in line for us. It might not be for everyone, but we're excited about it. I've gotten so slack in posting to my regular blog, I don't know if I'll ever get around to an entry about it. We shall see. :)

J.L. Murphey said...

I've been researching marine batteries like for boats too for the short term. They don't have a longer lifespan like the regular 12 or 24 volt solar batteries, but something is better than nothing. My dream solar batteries are the Edisons, but super expensive. Some are going strong after 10 years of use.

Cockeyed Jo

Toirdhealbheach Beucail said...

Thank goodness Glen responded. He is the local expert I know of.

I do like your idea of limited power usage supported by solar - is wind a possibility where you are?

Leigh said...

Unknown, I thought I replied about looking into the marine batteries, but after reading Jo's comment I realized I didn't! Or at least I did only in my head. :o I did look into marine and RV batteries, but the only ones I could find locally were "dual" and listed cranking amps, not amp-hours. So I concluded they weren't what I was looking for.

Su Ba, it sounds like your experience almost exactly parallels the authors of Prepper's Total Grid Failure Handbook, from golf cart battery DC system to the chest fridge. After reading their book that seemed the right way to go, so trying to start from where we are now feels a lot like going backward. Having such a limited budget really puts a damper on things, especially now that I've crunched the numbers. (And I agree about the odd number batteries; that was just the number I got in the calculations, so that's what got recorded on my blog.) Even so, I appreciate your taking the time to detail your system. Interesting and very helpful.

Kelly, that plus a backup generator sounds like it will serve you well!

One of the systems Dan and I looked at awhile back was the Smartflower. It was actually more reasonable than the other systems we saw quoted, plus, it is definitely more attractive.

Jo, Edison batteries, oh yes! The ones I found were listed at something like $1000 per amp-hour, so that was that! Still, the lifespan is extremely appealing (I read up to 30 years), and over those years probably levels the cost out.

TB, yes, Glen gave me a lot of good information! When we first moved here we thought about wind. But we really only get good winds several times a year, so that doesn't seem to be at all feasible.

JayNola said...

Have you considered that you only need to run the appliances a portion of the day, possibly only during daylight hours?

Nancy In Boise said...

Good info!

Leigh said...

JayNola, do you mean like to turn them off at night? No, I hadn't really thought along those lines. If I could get away with that, then they'd be powered by the solar panels on sunny days and need to use the batteries only on an heavily overcast day. I don't know if that would keep them cool enough during the night or not. Supposedly an unopened fridge can keep food chilled for 24 hours; I think it's several days for a freezer(?)Honestly, I'm not really sure when they run, I just know it's not all the time. Might make for an interesting experiment.

Nancy, thanks!

Chris said...

Interesting discussion on the concept of cool cupboards. I wonder if we're talking about the same design? As I've heard it being used successfully in areas such as Melbourne and Syndey (Australia). Both can experience humidity problems during summer.

From what I understand, you need hot hair above the system, to drive the air flow. Like venting the heat from a fridge, into the top part of the pantry. It draws the cool air up, and doesn't allow condensation to form in the bottom of the pipe.

We had a similar issue with an old fridge. The fan inside it, was blocked by food particles. We didn't realise this, until noticing water collecting under the vegetable crisper. Every time we opened the fridge, we were letting warm air in. Closing the door, is meant to engage the fan and thermostate, to normalise the temperatures again. The problem of condensing water, was fixed once we removed the obstruction, and the fan could work again.

Likewise, if the cool cupboard isn't insulated properly, it will absorb the ambient termperature of the house. Which are traditionally warmer. This will cause humidity inside the cupboard, which may end up in the pipe. Good air-flow can help, but if it constantly has to deal with hot air, coming in, then it may well cause condensation. So adequate ventilation and insulation, are essential.

I also wonder if pipes in the Northern Hemisphere, which aren't dug under the frost/freeze line, actually freeze in the winter, crack upon the thaw (as the soil heaves) and constantly has moisture entering the pipe, thereafter? Because that's one thing we don't have in Australia (in most places) is a problem with soil freezing, and heaving in the thaw.

I'm no expert on cool cupboards, just sharing the design features of them, and where problems might arise. If you want to see how to vent a fridge into a cool cupboard, see this link:

I find the whole concept really fascinating - using thermal energy to control themperature. Because it uses kinetic energy, between hot and cold. Which is freely available all around us, thanks to climate and microclimates.

Leigh said...

Chris, yes, that's the idea I had in mind but I've only read descriptions based on pre-electric homes in our Southwest, where the climate is hot and dry. I've never seen a photo or read an account of someone actually using one; it's just something recorded as old-fashioned skills and technology. So that they are successful with high humidity is extremely interesting. Especially how they vented the fridge through the cupboard, because I've realized how counterproductive it is when the fridge has to run more to counteract the very heat it makes itself.

In one of her comments above, Su Ba mentions a chest fridge. I've thought that is an excellent idea as well, because it keeps the cold air inside the chest, not spilling out onto the floor every time the door is opened.

You're right about frost lines, and that's a concern in this country. The farther north you go the deeper things are buried. We don't get frost heave where we live, because the ground never freezes more than about half an inch.

Thanks for the link! We're discussing options and collecting ideas at present, so all information helps. :)

Chris said...

Apparently the vacuum caused by venting the fridge into the cool cupboard, also helps draw heat around the fridge, away. So it gets a benefit, from the set-up too. I imagine it would reduce the cost of running a fridge during summer, but I don't know by how much. It may be a negligible saving, or it could be more.

The places I know which have achieved a successful cool cupbard, is Abdallah House (Melbourne) David Holgrem's permacutlure property, called Mellidora (also in Melbourne) Lewisham House in Sydney (New South Wales) and finally another permaculture property, called Bandusia (also in Sydney).

They're the ones which provide information online, about it anyway. Google one of those names, along with "cool cupboard" and you'll see more information. I actually purchased David Holgrem's ebook about his property (many moons ago) which is how I first came to hear about, the design behind a cool cupboard.

Separate information (to cool cupboards) my husband discovered is tiling your pantry floor (and walls part way, if you can) with stone. If there is cool air in the pantry, it will absorb it and hold it, helping to keep temperatures lower for longer. I'm going to try this idea in our standard pantry. But first I'm deciding if there's a way to expand it. I would like more storage for stockpiling canned goods.

I know you'll research thoroughly, before deciding on a plan that's right for your location. It's the design, which is really the key. You may stumble upon something completely different too. But it's a worthwhile pursuit, to see how you can be less dependent on electricity. I've enjoyed reading all the comments you're receiving too.

Rain said...

Very smart Leigh. Alex and I have recently started to measure our electrical usage, though we are using a calculator on a utility company's website, I think that wattage meter is a good buy. I can only imagine how much electricity our old fridge uses, it's criminal. We are only buying energy star appliances from now on. The new cheese cave is energy star so it's a good start. With regards to the deep cycle batteries, I head they need to be replaced every 5 years, did you hear different (HOPEFULLY??)

deb harvey said...

i know nothing technical but will add this new appliances are built with planned obsolescence and are made to last not much longer than 10 years
were you to get a new fridge add this info into your calculations
if your old fridge is a long lasting one it might pay to keep it

Leigh said...

Chris, from my understanding that's how it works. Warm air rises, creates low pressure in the shaft, and draws cool air up from below. I first read about these is Anita Evangelista's How To Live Without Electricity And Like It. She called it a "cold shaft" and mentioned that they were used in the 1920s in Southern California. On the site you linked to, Dan noticed that the fridge was enclosed and said we could likely do something similar without building the pantry. Although I would love that type of pantry. Our house is small, however, so we'd have to do some serious figuring out where to put it. Good idea about the stone!

We're collecting as many ideas as we can and will gradually sort them out into more or less feasible. We really want to figure out how to be less dependent on electricity.

Rain, measuring your usage is the place to start! I was amazed at how much of a difference the energy star fridge usage was. Good on you for getting an energy efficient cheese cave!

In regards to deep cycle batteries, it depends on the kind of battery you get. Flooded lead acid batteries are the most common and the cheapest, typically with a life span of 4 - 8 years depending on your conditions and how well they're maintained. AGM (Absorbed Glass Matt) batteries also last 4 - 8 years but cost considerably more. But people like them because they are sealed, so no off-gassing and maintenance free. Lithium Ion batteries can last 10 to 15 years, but are expensive. And if money is no object (I wish!) Nickle Iron (aka Edison) batteries can last 30 or more years, but they are outrageously expensive, at least to someone like me. :)

The other thing to be aware of is the difference between deep cycle and starting (cranking) batteries. Starting batteries are designed for an initial heavy draw such as starting an engine. Deep cycle batteries are made to provide lower amounts of electricity long term, like a golf cart.

Deb, that's a very good point. Sad but so true. The only way for a new fridge to pay, is because we could save several times that in battery costs. But it's kinda moot considering our budget, so we're stepping back to take a look at all parts of the puzzle. Then we'll figure out our best options.