We get this question often: “I want to put my house on solar. How much will it cost?”

If we just pull a number out of our behind, chances are, it’s for a grossly over-dimensioned system that fails to optimize resources based on your needs. That’s why most solar installers quote ~$50k for off-grid systems.

On the other hand, by understanding our clients’ needs and usage patterns and helping them make sensible tradeoffs to lower costs without compromising their lifestyles, we typically deliver full-house off-grid systems in the $20k neighborhood.

So, what factors drive up the costs of an off-grid solar solution, and how can you address them without compromising what’s important?

What goes into an off-grid solar system?

Solar equipment, of course, accounts for most of the cost.

Solar panels: Well, they turn the beams from the sun into power! The more total energy you consume, the more solar panels you need.
Solar charge controllers (SCC): They manage electricity flow between solar panels and a battery bank. To maximize solar yield, we typically put eight panels on one SCC. So, the more panels you have, the more SCCs you’ll need.
Inverter: The more power you use at a given moment or the higher the surge power, the more inverter capability you require. For instance, you need a more powerful inverter to run a kettle, a toaster oven, and a microwave simultaneously than if you run them sequentially.
Batteries: Besides storing power for nighttime use, batteries provide an extra jolt for appliances with high surge power requirements. If you have high demand during the night or run a lot of monster power tools, you’ll need more battery capacity.
Voltage systems: Most solutions are 24V or 48V. Equipment for 24V systems is lower in cost. However, a 24V system requires thicker cables, which can drive up costs.
Wire and cables: The price of copper is high, and pulling wires can run into money. So, we take solar field and equipment placement into account when planning a solution.
Fuses, ground rods, and safety measures: They don’t take up a big chunk of the cost, but are worth mentioning because it’s absolutely not worth cutting corners in this department!

The total power required throughout the day impacts the number of solar panels and SCCs you need. Your nighttime power consumption determines battery capacity. Meanwhile, a high surge power requirement means you may need a big battery bank or specialized cells.

(Note: More nuances are involved in balancing solar production, SCC configurations, and battery absorption. That’s where we do the nerd thing and crunch the numbers for ya.)

Factors affecting the cost of an off-grid solar solution (and how we address them)

So, what does it look like when the rubber meets the road?

When we design a system, we measure a client’s usage over a day or two with our proprietary tool to understand the total power consumed, the usage pattern (day vs. night), and surge power requirements to right-size each solution.

Then, we dig into a few “usual suspects” to see if we can help the client lower the system’s cost with reasonable adjustments and tradeoffs.

Well pump

The well pump is often our nemesis because, for some crazy reason, 80% of people in Caliente have agricultural well pumps for residential use! These big pumps have high surge power, requiring many solar panels to jolt them into action. Yet, they only run for a minute or two in an hour (because they draw so much in one go) and stay idle for the next 59 minutes.

What does it mean in dollars and cents? A client with a 1.75 HP pump requires a system in the $10k range, while one with a 0.5 HP pump can run theirs with a ~$4k system.

Unfortunately, unless you’re ready to yank out your pump, there isn’t much you can do about it. You may try setting up a soft start to reduce surge power. If you have a monster well pump and a gravity-fed tank, we may recommend keeping the pump on Edison (for those using our Resiliency Packages) or running it on a generator. The gravity tank will hold enough water to ride out an outage, or you can run the generator once or twice a week to fill the tank.

Water heater

Tankless, instant heaters are big power hogs. The surge power can reach 12,000W+, meaning you’ll need a lot of inverter capacity to take a shower. And if you want to do so at night, you have to dimension your battery bank to handle that demand as well (and batteries are expensive).

On the other hand, if you use a regular tank water heater with a moderate heating element, you can draw a reasonable amount of power over an hour or two to heat the water without buying a crap ton of inverter power you won’t need any other times. Propane-fueled instant water heaters are fine, too, because their electric demands are usually modest.

Plus, if you put the appliance on a timer and only heat water during the day, you don’t have to dimension the battery bank to handle that demand. Water can store a lot of energy, so in a way, you’re using your water tank as another battery!

Heat-generating appliances

A hot plate, toaster, and electric kettle here or a hair dryer and a space heater there don’t seem like a big deal, but resistive heating equals high continuous draw, increasing your solar production and inverter requirements (and battery capacity, too, if you run them at night).

The good news is that cultivating awareness of what draws power goes a long way to help you modify your habits. You may also consider using alternatives that run on other fuels.

Most of our clients either use propane dryers if they’re completely off-grid or keep their electric ones on Edison if using our Resiliency Package (whipping out a drying rack during an outage is not too unreasonable a compromise!)

A diesel air heater does a good job of heating small spaces (e.g., a cabin or trailer). We also help our clients install reversible mini-splits (the most energy-efficient air conditioning option) so they can use solar for both heating and cooling year-round to maximize their investment.

Monster power tools

Many people here have a power tool or two (or a few) in their shed. They can be tricky business — while the total power requirement may not be substantial (they often don’t run for long), your solar system must be able to handle the startup loads. Moreover, many power tools are 240V, another factor that drives up costs.

For example, a circular saw may run at 1,500W but surge to 5,000W. Besides a sizable inverter, you’ll need enough battery capacity to support the startup power. A client with an enormous industrial welder would have to pay an extra ~$4,000 for his Resiliency Kit if he wanted to run his welder during outages (our recommendation: Don’t do it, even though that means more sales for us… let Edison do the heavy lifting when the power is on.)

If a client uses beefy power tools once in a while, we generally recommend that they put it on Edison or a generator so that they don’t have to pay for an inverter or battery power to cover that need. Meanwhile, our surge-and-sustain custom battery pack supports mobile applications or frequent off-grid use.

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No matter where you are in your energy independence journey, knowing what goes in and what comes out is the key to getting the most out of your investment. Whether you need to build an off-grid system from scratch, fine-tune an existing installation, or perform an energy efficiency audit to help you do more with what you have, we can help.

4 Things That Drive Up Off-Grid Solar Costs (and How To Lower Yours)