Off-Grid Solar
Off-grid solar is becoming more popular as an alternative to grid power for new home construction. It may be more economical in the long run than getting a grid connection, especially in remote locations.
It's important to note that the designing, planning, and pricing of a fully off-grid power system is much more involved than a typical grid-tied system. This guide dives into this topic to help you understand the details about going off-grid, so you can make an informed decision if you're considering off-grid power for your new home, and if it's right for you.
Living off-grid is more than just a way to save money. It's a lifestyle choice that requires a commitment to understanding, monitoring, and managing energy use, knowing and maintaining your own power supply, and being independent as much as possible.
We evaluate off-grid projects carefully and proceed only if we're confident that it will result in a satisfactory outcome. If you're interested in learning about energy and power, embracing self-sufficiency, and having an energy-efficient lifestyle, then off-grid may be right for you.
Note: Homes that are already grid-connected can also achieve energy autonomy through the implementation of backup systems.
Here are some of the key points to consider before planning an off-grid home:
Consult with us before finalizing the home design or starting construction. We offer consultation services for design and planning (beyond our initial free recommendation and estimate).
The home construction methods and electrical system design must be planned to be energy efficient. We discourage attempting off-grid for large homes, tiny homes, or trailer homes. We do not install off-grid systems for vacation homes, rentals, or campgrounds.
For backup power, you must have a propane tank and a standby whole-home generator installed (by others) that is approved by the manufacturer for off-grid homes.
The generator must also include a transfer switch, allowing the generator to bypass the battery system and power the home directly.
We only service equipment that we install. We do not service generators.
Uninterrupted power is not guaranteed. When energy resources are low, power may turn off briefly while a backup generator takes over. In other cases such as system faults, power outages may last longer. It is the responsibility of the homeowner to have someone on-site for troubleshooting in case our service is not immediately available.
We do not assume responsibility for any incidental damages due to power outages.
Water lines must not be dependent on power (i.e. heat tape) for freeze prevention.
There must be internet access on-site for monitoring and troubleshooting.
Homeowners must use the system monitor to be familiar with the system's performance and state of charge. The installer may remotely view system characteristics for evaluation and troubleshooting but does not regularly monitor the system.
Electric heating is not recommended, as it will rapidly deplete and overload the battery; other energy sources for heat such as propane or wood are necessary.
In most cases, ground-mounted solar arrays are required for off-grid homes for easy maintenance and improved winter performance.
Power systems will not be activated until construction is complete and inspected and internet access is available. Contractors must use their own generators.
We do not sell or service wind turbines or other power sources.
We are unable to offer 24/7 or emergency service, and service times may vary, so we strongly recommend learning how the system works and being willing to contact the manufacturer for support when needed.
Building Efficiency
When it comes to building a home, going for cheaper options may actually end up being more expensive in the long run. Investing in quality construction is crucial for building a home that lasts. It's important to prioritize building efficiency in order to achieve cost-effectiveness and comfort over the long term. This is especially beneficial for an off-grid power system. A well-built home requires less energy to heat and cool, which is particularly important in a winter climate where most energy consumption is related to heating.
By optimizing building performance for climate control, it's possible to significantly reduce the size and cost of the power system required while also improving reliability. Investing in higher-quality construction and efficient appliances will also offset maintenance costs over the life of the home.
A quality building envelope is the most important design choice for energy conservation. High-performance homes incorporate:
High insulation value (R-40 walls, R-60 ceiling, under slab and footing insulation)
an air-tight envelope (confirmed by a blower-door test)
and energy-recovery ventilation (ERV) to keep the air fresh and control humidity
When designed and built with energy conservation in mind, new homes can significantly reduce energy consumption compared to an average home. New homes built for energy conservation can use as little as one-third the energy of a typical American home, though occupancy and usage are also significant factors.
The Top Energy Consumer is Heat
When planning an off-grid home, it is important to consider the energy needs for heating during the winter months, as this is typically when the highest energy consumption period aligns with the lowest available solar energy. We recommend installing two or more sources of heat with little or no electric heating. Given the importance of keeping a building above freezing temperatures, good planning and building design is essential as this will keep your home safe and comfortable without depleting its energy.
Combining heat pumps with an additional source of heat, such as a propane furnace or wood stove, is recommended. Heat pumps are highly effective even in cold temperatures, but a secondary heating system is necessary for extremely cold weather. This setup allows for energy efficiency and comfort by using the heat pump during mild temperatures and the secondary source when the temperature drops.
It is essential to consult with an expert HVAC contractor to determine the best heating options for your building design, as it will vary depending on factors such as the building size and layout, exposure to sun and wind, ducting and ventilation options, among other factors.
The Power System
An off-grid solar power system works by using photovoltaic (PV) solar panels to convert sunlight into electricity, which is then stored in a battery or bank of batteries. The solar panels provide power directly to the home, while also charging the battery throughout the day. The stored energy in the battery is then available for use at any time.
The battery system is typically located in the garage or a mechanical room, where the main electric breaker panel is also located. The battery system requires a minimum of four feet of lateral wall space and three to nine square feet of floor clearance, so a closet or crawlspace is not acceptable.
When there is above-average power use and below-average sunshine (typical in the winter time), a standby generator (typically 14 to 24 kW) will be available if the battery runs low. An automatic transfer switch should be used so that it is possible to power the home directly from the generator.
To improve system functionality and battery longevity, some off-grid homes also use a smart breaker panel for automatic load controls. This allows the home occupants to improve power management and maintain the battery capacity more easily.
System Sizing
Sizing an off-grid solar system starts with determining the number of solar panels and battery capacity required to meet all of the home's electric power usage throughout the year.
An average South Dakota home's energy consumption is about 12,000 kWh per year or an average of 30-40 kWh per day. Energy consumption is typically highest during the winter months. However, every building and its occupants are unique, so each situation needs to be considered individually. Factors such as construction quality, appliance efficiency, and conscientious occupants/users all contribute to determining if a home will consume as little as 30% of the average or up to 5x the average.
The power capacity of the battery system must be able to meet, at a minimum, the single largest load. On average, power requirements are as follows:
5 kW for a minimalist system or small home
10 kW for a moderately-sized efficient home (usually <2000 sq ft)
15-20 kW for larger homes
20 kW+ for very large single-family homes and/or having high power use
Appliances
When living off-grid, it's important to consider the energy usage of major appliances, as they are typically the biggest consumers of electricity. Larger appliances that are used frequently, such as the refrigerator and washing machine, have a greater impact on energy consumption than smaller appliances and electronics.
To achieve the best experience with off-grid living, it's important to plan your home with energy efficiency in mind.
Ventilation:
A blower-door test is recommended to test the air-tightness of the building and address leaks.
Mechanical ventilation is essential for high-efficiency homes with a tight building envelope. This includes heat-recovery ventilators (HRVs) and energy-recovery ventilators (ERVs) that exchange indoor air with filtered outdoor air with minimal heat gain/loss.
Whole-house fans (large exhaust fans) can be a good alternative to an active mechanical ventilation system, but the air is not filtered and temperature/humidity will not be recovered or controlled.
Heating, Ventilation and Air-Conditioning (HVAC):
Air-conditioning works well with solar power since cooling is needed most when there is the most sunshine.
Air-sourced heat pumps are efficient for cooling and can be installed as part of a central-air ducted system/furnace or wall mount.
Mini-split heat pumps are good for cooling individual rooms. Multiple units may be used to serve certain areas of the home only as needed.
High-efficiency central air conditioners are acceptable, but avoid oversizing as it is typically more efficient to run at lower power for more time.
Ground-sourced heat pumps can be effective, but have a high cost and don't work well in all situations. They should be used only when carefully planned, with expert guidance, and in the right locations.
Electric (resistive) heat is limited to use in milder temperatures in smaller spaces and highly-efficient homes. Alternate heat sources are strongly recommended when off-grid at (or above) our latitude. Larger homes may prefer to have more than two heating sources and/or multiple zoned systems.
Water:
For water heating, a large hot water tank with electric elements (or a hybrid electric/propane tank) is preferred. With a timer or controller, extra solar power can be used to heat the tank during the day and not require energy at night.
An on-demand propane water heater can also be a good choice.
Do not install an on-demand electric water heater (as the power requirement is too high in most cases).
A combination of a small electric tank that preheats water going into a small on-demand propane water heater can offer the advantages of both options.
Many well pumps require a high-power start and therefore need to be fitted with a soft-start capacitor (for smaller pumps) or VFD controller (for larger pumps) to run efficiently and not overload the battery system.
For even greater resiliency, the well pump can fill a cistern for water storage at the surface during the day, and a small pressure pump (or gravity) can provide water pressure on demand with minimal power at any time.
Kitchen:
Induction cooktops are the most energy-efficient option for cooking, but a standard electric range is also acceptable. If using gas, ensure proper ventilation.
Most modern refrigerators and freezers are energy efficient and do not require special consideration. However, ice-makers use a significant amount of energy.
Dishwashers are relatively efficient and represent a small share of energy use. They can even be more energy-efficient than hand washing, especially when using efficiency settings.
Laundry:
Newer clothes washing machines are very energy efficient. A high-extraction (fast-spinning) washer is recommended to reduce energy use for drying.
Propane/Gas vented dryers are a good choice that requires little electricity. They are affordable, readily available, and easy to maintain.
Electric, vented (hot-air, resistive electric heating element) clothes dryers are extremely energy-intensive, inefficient, and potentially damaging to fabrics. However, they are the most affordable and widely used. A lower-powered option (under 5 kW) is preferable. Smaller dryers are not more energy-efficient, but they demand less power at one time in exchange for a longer drying cycle, which is generally more suitable with battery power. A high-powered dryer can be fine when running while there is sunshine or while the generator is running; at night it may trigger the generator to turn on in order to support the high load or recharge the batteries.
A condenser dryer (typically called "ventless" or unvented) is like a vented dryer except the extracted moisture is collected in a tank that must be emptied. These use slightly more power than a vented dryer, but dry clothes faster. Their efficiency is not significantly different from a vented dryer.
Heat pump dryers are considered to be more energy efficient than other types of electric dryers. This is because they use a heat pump system to recycle heat from the air inside the dryer, rather than generating new heat via an electric heating element. This allows them to use less energy overall and can result in significant energy savings over time. Additionally, heat pump dryers tend to run at lower temperatures, which can be gentler on clothes and may help to preserve their color and shape. However, heat pump dryers tend to be more expensive than other types of electric dryers, and they may take longer to dry clothes.
Electronics:
Power usage should be considered, as some electronics use power even when not in use. To reduce this, use power strips or smart switches to turn off power to home entertainment systems and gaming consoles when not in use.
Internet connectivity is essential for monitoring and updating solar and battery power systems, but it is important to choose a newer, more efficient modem and router as they need to operate continuously. Avoid rentals provided by internet service providers, as they may be outdated and inefficient. Satellite-based internet modems tend to use much more power than regular modems/routers, but Starlink is a low-energy satellite system.
When it comes to appliances, investing in high-efficiency options can lead to cost savings in the long run. These appliances may have a higher initial cost, but they will use less energy and have better overall quality. The benefits of these appliances include a smaller solar power system size, increased reliability, and improved performance.
Thank you for reading this guide!