Key considerations when selecting an off-grid solar system
Off-grid systems must be sized accurately to meet the household’s average and peak energy demands throughout the year and during adverse weather conditions. If the various loads and loss factors are not taken into account during the initial design process, this will result in poor performance, frequent power loss and even system failure. Learn more in our detailed guide to designing off-grid solar systems.
Key considerations when sizing off-grid solar power systems include:
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Daily energy consumption (kWh) – Summer and winter average using a load calculator.
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Peak loads (kW) – The maximum peak (surge) power demand.
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Maximum demand (kW) – Inverter maximum continuous load (30-minute peak).
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Solar exposure – Location, climate, panel orientation & shading issues.
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Backup power options – Generator for periods of poor weather or faults.
With the above considerations in mind, a critical component of an off-grid power system is the off-grid inverter, often referred to as an inverter-charger. They are not just an inverter but a battery charger and must be able to meet peak loads and maximum demand. Learn more about the best off-grid inverters in our detailed review.
How much do off-grid solar systems cost?
The cost of a home off-grid system can vary substantially based on factors such as system size and complexity. For example, an off-grid setup designed to power a small home or cabin with essential appliances and lighting typically ranges from $20,000 to $30,000 fully installed (excluding a backup generator). This includes 7 to 9kW of solar panels, batteries and enclosure, solar charge controllers, and a smaller capacity 4 to 5kW off-grid inverter. Mid-sized systems capable of powering efficient homes with modern appliances and electric heating/cooling generally fall within the $30,000 to $60,000 range. These systems incorporate higher-capacity batteries, more powerful inverters and larger 10 to 15kW solar arrays. For off-grid systems supporting larger homes or multiple buildings, costs can exceed $60,000 and may extend into the six-figure range.
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Small Cabin: $20,000 to $30,000 – 7 to 9kW Solar array, 12kWh battery & 5kW Inverter *
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Average home: $30,000 to $60,000 – 8 to 15kW Solar array, 24kWh battery & 8kW Inverter *
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Large home: $60,000 to $90,000+ – 20kW Solar array, 40kWh battery & 10kW Inverter *
(*) Many factors can affect the system size and cost, including whether the solar array is roof-mounted or ground-mounted, the roof type, the location of the system (exposed to weather or rain) and the distance from the solar array to the inverter. Underground cabling (if required) can also significantly increase costs and complexity.
Important Considerations
Every off-grid solar system differs due to individual household energy requirements, local climate and weather. System performance can vary dramatically based on geographical location (sunlight availability), potential shading (particularly in winter), building efficiency, consumption patterns (summer and winter loads), and the need for large backup generators or load monitoring. While the initial investment may seem significant, correctly designed and sized off-grid solar systems using quality equipment will supply reliable power for many years and offer long-term savings by reducing backup generator runtime and maintenance. It’s crucial for homeowners to conduct a detailed assessment, using a load calculator, together with a solar professional to determine the most suitable system size and features based on individual needs and budget constraints.