CHAPTER
20

Off-Grid Living

In This Chapter

• Discovering what off-grid living is
• Calculating how much power you actually need
• Learning how to go solar
• Water solutions for off-grid living

One of the aspects we’ve enjoyed the most in our experience of living tiny and minimally for four years has been being off grid. Our ritual of manually tracking the sun by turning our panels several times per day has gifted us with an intimate understanding of the seasons and climate. It feels good knowing where our power comes from and that we’re sourcing it as locally as possible.

Each property offers unique natural resources and discovering the gifts yours has to offer is a fun and rewarding process. In this chapter, we cover how to calculate your power needs, how to create solar electricity, and what to use as a back-up power source. We also discuss options for bringing water to your tiny house if your land is undeveloped. Let’s get you onto the path to power independence.

In an ideal world, everyone would be responsible for creating 100 percent of their energy and would have a reliable onsite water source. A lot of emerging technologies are getting us close to that point, but we’re not completely there yet. Hopefully in the next 10 to 20 years, we’ll see existing solutions become even more compact, available, and cost effective, so that we can reach the goal of total energy independence.

The Joys and Challenges of Making Your Own Power

Making your own electricity is fun! Even four years into being off grid we still marvel that the sun can generate our power. Another advantage of sourcing electricity from an onsite system is that the amount of energy dissipated during transit from power plant to point of use is decreased significantly, thus reducing the burden on the power grid and minimizing our reliance on foreign power sources.

Off-grid living fosters a lifestyle of mindfulness and connection with nature’s cycles. It can also be an opportunity for a bit of time travel and whimsy. Old technologies used by our own forefathers and -mothers can suddenly be helpful again: hand coffee grinders, metal flat irons, oil lamps, and so on.

There’s even a sense of romance in living off the grid. It’s so much nicer to sit around candles while drinking wine or tea with friends than underneath bright electric lights. Of course, while you can keep using your modern gadgets, you might enjoy a new lifestyle in which the Earth seems to spin just a little bit slower and you live in a day-to-day connection with the rhythms of the sun and weather.

TINY WARNING

If you’ve never lived off the grid before, you might experience a steep learning curve. There’s a lot to understand and perhaps even some lifestyle adjustments to be made. It’s all manageable, but it’s not as easy as just turning on a light switch or opening a faucet without any consideration at all. A lot of issues come down to planning and anticipating the day’s energy needs.

Basic Solar Terms

There’s a lot of jargon in the world of alternative power. We’ll introduce you to several terms throughout this chapter, but for now let’s start with very basic definitions:

Watts When it comes to sizing an alternative energy (AE) system, as well as assessing how much power an appliance uses, you’ll be evaluating the data in units of watts. When a product’s specification sheet states that an appliance uses 100 watts (100W), they’re referring to watts per hour. Not per day.

kWh 1 kWh (Kilowatt hour) = 1,000W (watts) sustained over an hour. This is the unit most often used by utility companies when talking about how much energy is being consumed.

Voltage If you imagine that electricity flows like water through a hose, voltage is the equivalent of water pressure. Your options for a solar system are 12V, 24V, and very rarely, 48V.

Amp An ampere (or amp) is the measure of the amount of electricity in a circuit.

AC power AC stands for alternating current in electricity. Conventionally built houses run off of AC power as do nearly all appliances.

DC power DC stands for direct current and is typically only seen in off-grid applications. Electricity is delivered from batteries as DC power. DC systems are more efficient because there’s no need for an inverter in a DC system (which loses a lot of power during conversion). However, DC systems require separate wiring and specialty appliances.

Amp hours (Ah) This is the amount of energy charge in a battery. This is the standard unit used to compare batteries.

How Much Power Do I Need?

Put your best foot forward when starting down the road to energy independence by choosing systems that are as efficient as possible. The efforts you make in selecting energy efficient insulation, appliances, and lighting will pay off in spades when it’s time to size up your AE system.

TINY TIP

Knowing how big your system needs to be can be challenging. You can calculate this information yourself or you can ask a solar installer for help. We highly recommend the good folks at BackWoodsSolar.com. Their focus is on DIY builders and their telephone support is outstanding. We’ve personally spent many hours talking with them over the years.

To estimate your AE system size, you’ll first need to take stock of all the appliances you plan on installing in your tiny house. A lot of online sizing calculators tell you to refer to current utility bills to obtain your usage numbers. This will be of no use unless you happen to live in a grid-tied tiny house already. Instead, you’ll need to research the energy loads of each appliance. Fortunately, this information can be easily found online.

In terms of calculating the power burden of your small appliances, the handiest gadget you can get is a Kill-a-Watt Meter. Simply plug this small device into any electrical outlet and install your appliance into the device’s power port. The Kill-a-Watt Meter will display various pieces of data about your appliance, including how many watts it draws.

Remember that watts are represented in terms of how much power is drawn per hour, not per day. So if you have a laptop that draws 60W per hour and you typically leave it plugged in for three hours per day, your daily electricity need to power it is 180W (60W × 3 hours = 180W).

Here at hOMe, we have a 1.6 kWh system. This is enough to power the following appliances daily for nine months of the year without any need for generator backup:

• 2 laptops, 6-8 hours per day
• 2 laptops (kids’), 2 hours per day
• 18-cubic-foot electric refrigerator
• 15 LED lights spread out amongst cabins
• LED TV screen, 2 hours per day
• DVD player, 2 hours per day
• Food processor, 10 minutes per day
• Clothes washer, 1 hour per day
• Propane clothes dryer, 1 hour per day
• Charging small electronics, such as smartphones, 3 hours each day
• Printer and scanner, 10 minutes per day
• Hair dryer, 10 minutes per day
• Propane water heater, 1 hour per day
• Composting toilet fan, 24 hours per day
• House bathroom and kitchen fans, continuous
• Generator, two hours per day during sunless winter to fully charge our batteries (A 5-gallon gasoline tank lasts one week)

We highly recommend the off-grid system size calculator on wholesalesolar.com. It’s comprehensive, free, and considers all the factors that play a role in an AE system. Once you have your watt estimate, you can take this information and apply it to any off-grid system you’re considering, whether it’s solar, wind, or hydro. Commit this figure to memory because you’ll refer back to it dozens of times while researching systems.

This chart gives an idea of how much power is drawn by basic tiny house appliances. Keep in mind that some appliances run continuously when powered on (for example, composting toilet fans, computers, TVs, and DVD players). However, some appliances run only intermittently on any given hour (refrigerator, water heater, printer, and the like). As you calculate how much power you need, make adjustments to reflect this because you likely won’t be printing for an hour straight or blending your food for more than 3-5 minutes at the most.

Solar Systems

By far, the most commonly utilized source of alternative power in a tiny house is solar. Compared to other solutions, solar is moderately priced, can be mobile, and is fairly compact. There are two other options: wind and hydro, but they’re so rarely used in tiny house applications, we’re going to stick to solar in this book.

Solar 101

Solar solutions used to be incredibly expensive, but they’ve become more affordable with each passing year. When you couple today’s prices with government rebates and incentives, you end up paying a mere fraction of what you would have just three years ago. You can find up-to-date rebate offerings by zip code in the United States on dsireusa.org.

Sometimes, building a solar system is much more cost effective than connecting to the grid. Bringing electricity just 400 feet from the road to our home site would have cost between $25,000-$30,000. Instead, we paid about $12,000 for our 1.6 kWh system and cashed in on 40 percent worth of rebates and tax incentives, lowering our total investment to $7,200.

Our system was quite expensive by tiny house standards because we power not only hOMe where we work full-time on our computers, but also both of our kids’ cabins and a pretty large electric refrigerator. There are complete solar packages on the market that can be bought in the $2,000 range. As we mentioned previously, the key is minimizing power needs in the design process.

TINY WARNING

If you plan on installing the solar system yourself, we recommend you hire an electrician for a final inspection to ensure that you’ve not created an electrical hazard.

There are numerous components that go into the process of converting sunlight to electricity. Though it seems like magic, there’s a lot of science behind it. Let’s go over how it works.

System voltage

For starters, you’ll need to decide on the system voltage (12V, 24V, or 48V) that’s best for your battery bank. A 48V system is really intended for much larger homes, so we can safely eliminate that option. A 24V system is appropriate for installations in the 1kWh-5kWh, whereas a 12V system is perfect for smaller solar systems. Most likely, you’ll be looking at 12V systems for your tiny house.

Charge controllers

These wall-mounted devices protect the batteries from overcharging when too much electricity travels from the panels. Without a charge controller, batteries can become permanently damaged.

To calculate the size of your charge controller, you must first determine how many amps are required. Divide your solar system size by battery voltage. For example, if you have a 700W system and a 12V battery bank, (700W/12V), you’ll have a 58-amp load, which can be met by a 60-amp charge controller.

Inverter

If you want to run standard (AC) appliances in your tiny house (not specialty DC units), you’ll need an inverter to convert the DC power emitted by the battery bank into AC current. Because inverters are one of the most expensive components of a solar system, we recommend you purchase a unit larger than you think you’ll need just in case you end up expanding at any point in the future.

You can roughly calculate the inverter’s size by establishing your tiny house’s peak load. To do this, add up the wattage of all electric appliances that might run simultaneously in a peak hour of usage. This sum will tell you the minimum inverter size you need. Choose a Pure Sine Wave inverter for a steady current, which will protect appliances from any surges.

Batteries

Deep-cycle batteries are ideal in solar applications. Preferably, you’ll invest in solar specific models to get the most out of your system. Flooded deep-cycle batteries are used most commonly in off-grid applications. They’re affordable, easy to maintain, long lasting, and reliable.

The formula for calculating how many batteries are needed is somewhat complex.

1. Multiply your daily estimated power need (for example, 800W) by 1.5 to create a buffer for those times when there’s heavier usage (800W × 1.5 = 1.2kWh).

2. Decide how many days you want to have power stored before needing to recharge batteries (for example, two days). Bear in mind that the more days you add, the more expensive your system will be.

3. Multiply the buffered daily wattage estimate by how many days you want power autonomy (1.2kWh × 2 = 2,400).

4. Next, multiply this number by two (2,400 × 2 = 4,800).

5. Divide this number by 12V or 24V depending on which system voltage you chose. For this example, 4,800/24V = 200Ah. That means your minimum Ah capacity is 200Ah.

6. Divide this number by your battery’s rating and you have the number of batteries needed.

TINY TIP

Many tiny house folks end up installing batteries on the tongue side of their trailers in small custom-made utility closets. Remember to factor this weight into your load distribution calculations to ensure a safe and pleasant towing experience.

Batteries are extremely heavy and can weigh more than 100 pounds each. Finding a place to install them in a THOWs is challenging not only because of this weight, but also because they require venting to the exterior.

Solar Panels

There are various options on the market and they differ in material, size, power capacity, and cost. Solar panels can be installed on THOWs roofs, but remember that overall height is measured to the tallest point of a trailer. Make sure you stay under the legal height limit.

Consider installing some type of removable protective panel that can cover your panels while you’re in transit so as not to damage them. Park your THOWs so that the solar panels face south. To maximize solar gain, mount the brackets on the roof so they install at approximately a 30° angle.

This image of Andrew shows the size of a 1.6 kWh solar array mounted on a pole. The pole is 8' deep and supported by tons of poured concrete to prevent any uplift in case of high winds.

You can find tiny house–appropriate solar solutions and options in the RV industry. Look for roof-mount options as well as portable solar kits. For example, depending on your power needs, you could potentially get away with the totally portable Goal Zero Yeti 1250 Solar Generator, which weighs just 103 pounds. The Goal Zero solar panels can be roof-, wall-, or ground-mounted.

Use these steps to calculate how many panels are required:

1. First, you’ll need to know your daily power needs (for example, 800W).

2. Add a 25 percent cushion to that value (800W × .25 = 1kWh).

3. Calculate how many hours of sunlight you can expect in your area (found on the internet on a solar map).

4. Divide your daily kWh needs by the number of daily peak sunlight hours, which is five hours in our area. That means, 1,000/5 = 200.

In this example, a 200W solar panel sitting in four hours of sunshine should produce enough electricity to get you through the day.

Back-Up Power

When the sun isn’t shining and the 10-day forecast looks bleak, you’ll need a way of charging your deep-cycle batteries. The most common back-up source is a gas-powered generator. There are numerous models and sizes out there, so choose the one that can recharge your battery bank’s capacity.

Spare any neighbors (and yourself) tons of noise pollution by choosing a unit with whisper-quiet technology. Seek out models with an eco-throttle option and save on gas, too. If you don’t plan on running large power tools from your generator, a smaller one should do the trick. If you plan on being mobile, you’ll likely place the generator in the living area during transit and then move it outdoors once you’re parked.

Sourcing Water

If you plan on parking or building your tiny house on a rural piece of land with no existing water services, you’ll need to find a solution. The most common solutions are wells, rain catchment, and water delivery services.

Making a choice between the three is largely a function of how long you intend on living on the land and the size of your budget. The most expensive solution is typically a well. If you don’t plan on living in the same place for more than five or so years, you might want to consider the other two options.

Well

A well is typically the safest and most reliable water source on rural land. Unfortunately, wells can be very expensive ($3,000 to $15,000 or more) and represent a major investment in a tiny house budget. The well on our property cost $8,000 and ended up being 280 feet deep.

TINY WARNING

Despite modern day technologies, it can actually be very challenging to pinpoint the best location for drilling a well. The best that companies can do is survey geologic maps, look at well records for the area, and analyze other pieces of data. Ultimately though, there’s no guarantee that they’ll find water and whether they do or not, you’re the one stuck with the bill.

When looking for land, always speak with neighbors and look at well records. Not every place has water that can be reached by drilling a well. For example, there are some areas in New Mexico where even 800-foot deep exploratory holes yielded no water.

Once your well is drilled and cased, you’ll need to get the water from the bottom of the well to your house. For this, you’ll need a pump and pipe attached to a rope, which is lowered into the water column. You’ll also most likely need a pressure tank. This tank stores water under pressure and supplies flow to each point of use as needed. Pressure tanks are too large to be installed inside a tiny house, so they must be placed either in a pump house or some other structure.

A great alternative to a pressure tank is a gravity-fed system. If you have a hill on your property and plan on building below it, you can set up such a system. Place a 500-gallon storage tank about 100 feet above your tiny house. Plumb your system so that a buried water line carries water from your well to the holding tank, and another travels from the tank to your tiny house water shut-off valve.

A gravity-fed system spares the off-grid homeowner the expenditure of a larger solar system needed to power a pressure tank. This is the setup we have here at hOMe and it works perfectly. We manually kick on our well pump once every four to six weeks on a day we know we’ll get about four hours of direct sunshine on our panels. This is about how long it takes to fill our 1,500-gallon storage tank. The rest of the time, gravity does the work for us and provides adequate pressure for comfortable showers and for our water heater.

Trucked-In Water Systems

If a well is out of your budget or you don’t plan on living on the same piece of property for more than a few years, you can always install a storage tank and have water trucked in. A 1,500-gallon tank holds enough water for full-time use by four adults for about four to six weeks.

TINY TIP

A tiny house with only one or two occupants could likely get away with just a 500-gallon tank. It all depends on how often you want to get it filled and how much space you have on your land to store a tank.

Storage tanks aren’t terribly expensive and can even be found used. You’ll need to install a pump (unless gravity fed) inside to deliver the water to your tiny house. These systems are quite simple and are certainly within the grasp of the DIY builder.

A pump placed at the bottom of the cistern will make easy work of delivering water to your tiny house. If you plan on drinking this water, use a metal roof on your tiny house as some other materials can contribute a lot of toxins. Install a high-quality filtration system to ensure your drinking water is free of any contaminants.

TINY TIP

A 1" rainfall on a 200-square-foot roof can gift you with 150 gallons of beautiful fresh water.

If your area only receives seasonal rainfall, you might want to consider installing more storage tanks or creating a hybrid rain catchment/water-delivery system. This allows you to take advantage of free and local water when the getting’s good, but not run out during dry months.

TINY WARNING

Believe it or not, some states own the rights to rainfall and make rain water harvest illegal. However, most have no restrictions whatsoever, and some states even have special incentives in hopes that the burden on municipal water systems might be somewhat abated. Check in with your local regulators to make sure you won’t have any issues.

The Least You Need to Know

• Some believe that any reliance on any outside power/fuel source disqualifies a property from being truly considered off the grid.
• Sizing up your alternative energy power needs is a big step in moving toward power independence.
• Solar systems have become less and less expensive and government rebates and incentives have increased in recent years, making this a great time to go solar.
• Water solutions exist for off-grid applications even if you don’t want to drill a well.