The off-grid lifestyle is one of independence, self-sufficiency, and self-reliance. Whether to achieve an ideal, achieve autonomy, or eliminate the cost of a grid interconnect, living off-grid can offer greater resilience compared to homes that are dependent on the grid.
(A home that is already grid-connected can attain a similar degree of autonomy, which we call a "backup system".)
However, off-grid solar is not for everyone and may not be practical in every situation. In some cases, the amount of power a home (or the occupants) needs is excessive and better suited to a grid connection (and high power bills). Also, some people do not like to have an energy budget, monitor their usage, or limit their power use to what's available on a daily basis, while others are very keen to maximize efficiency and conservation. It is also essential that the homeowners are committed to becoming familiar with how the power system works. Our expert advice will help guide you, and the information below offers a good start for the essentials so you can plan ahead and get the best results.
The best-case scenario for an off-grid home is always during new construction when there is the most opportunity to build optimally, maximize energy efficiency, and avoid a high grid-interconnection cost. Unfortunately, most average homes are not built to high standards in exchange for cost efficiency, but a retrofit home can become better suited to energy independence, especially during a complete remodel.
A high-performance home will always be more reliable and cost-effective (over time) than a conventional, energy-intensive home built at a budget price. This is especially true for off-grid homes, and even more important in a winter climate. The majority of energy consumption in most buildings is related to heating and cooling, so optimizing performance and efficiency for climate control is significant. The costs of having a higher-quality home and appliances can be offset by not requiring as large of a power system.
A quality building envelope is very important to ensuring energy conservation where needed most. Efficient homes have:
High insulation value (R-40 walls, R-60 ceiling, under slab and footing insulation),
an air-tight envelope (confirmed with a blower-door test),
and heat-recovery ventilation (HRV) to keep the air fresh without temperature loss.
New homes, when built for energy conservation, can get down to one-third of the energy use of an average American home. This in turn reduces the capacity and cost of the power system while providing a more comfortable and reliable home overall.
Winter capacity / Heating
Rule of thumb: if the power system capacity is sufficient for the wintertime, it will be sufficient for the rest of the year. This is especially due to space-heating needs, which is generally the biggest energy consumer and is used most when there is the least sunshine.
It is best to have two sources of heat other than electric heat. For primary heating, it is usually best to have a combination of:
a heat pump (for milder temperatures) and
a propane furnace and/or wood/biomass stove (for freezing temperatures).
Only the highest-rated (i.e. LEED-certified) homes may rely on electric heat (or heat pump) primarily.
Ultimate, the preferred heating options vary depending on several factors including the building size, complexity, floors, basement, and ducting and ventilation options. With this basic guidance, an expert HVAC contractor can offer what is best for your particular construction.
How the system works
The home is powered by a battery (or bank of batteries) installed in the garage or a mechanical room, usually where the main electric breaker panel is located. If all equipment is located in one room, the wall space required is typically around 6 feet (with about 3-1/2 feet floor clearance off the wall).
Solar panels provide the home's power directly while simultaneously charging the battery throughout the day.