Solar Panels for Garages and Sheds
A detached garage, workshop, or shed often sits far enough from the main electrical panel that running a new circuit out to it is expensive and disruptive. A small, dedicated solar setup is frequently the simpler and cheaper alternative — but the right approach depends heavily on what you’re actually trying to power.
Table of Contents
- Why Solar Makes Sense for Detached Structures
- Step 1: Figure Out What You’re Actually Powering
- Off-Grid vs Grid-Tied for a Detached Structure
- Sizing a Small Off-Grid System
- Typical Costs
- Permitting Considerations
- FAQ
Why Solar Makes Sense for Detached Structures
Trenching a new underground electrical circuit from your home’s panel out to a detached garage or shed involves digging a trench, running conduit, and often a permit and inspection — costs that can add up quickly, especially over longer distances. A self-contained solar setup skips that entirely: no trenching, no new circuit on your home’s panel, and no dependency on your home’s electrical capacity.
Step 1: Figure Out What You’re Actually Powering
The right system size depends entirely on your actual loads:
- Lighting only — a very small system (often under 100W of panels with a small battery) can comfortably run LED lighting for hours each evening.
- Lighting plus occasional power tools — needs meaningfully more panel wattage and battery capacity, plus an inverter sized for tool startup surge, particularly for anything with a motor (table saws, compressors).
- Workshop with regular power tool use, a mini-fridge, or a space heater — approaches the sizing of a small off-grid cabin system and may be worth comparing against the cost of running a proper grid circuit instead.
- EV charging or major appliances — almost always makes more sense as a grid-tied circuit run from the home rather than a standalone solar setup, given the sustained power draw involved.
Off-Grid vs Grid-Tied for a Detached Structure
- Off-grid (standalone) system — solar panels, a small battery bank, and an inverter, entirely independent of your home’s electrical system. This is the simplest and usually cheapest option for lighting and light-duty use, and avoids any permitting tied to your home’s grid interconnection.
- Grid-tied circuit from the home, supplemented by solar — makes more sense when the structure has heavier or more consistent power needs (a workshop with regular tool use, a heated space), since it avoids the battery capacity and inverter surge limitations of a standalone system.
Sizing a Small Off-Grid System
The same basic sizing approach used for off-grid cabins applies at a smaller scale: total your daily watt-hour load, multiply by your desired days of autonomy (1-2 days is often sufficient for a garage or shed, since it’s not depended on for continuous living), and size the battery bank around your target depth of discharge. A basic lighting-only setup might need only 100-200W of solar and a small LiFePO4 battery, while a workshop with regular tool use can require 400-800W of panels and several kWh of battery storage.
Typical Costs
A basic off-grid lighting system for a shed can often be assembled for a few hundred dollars in equipment. A more capable workshop setup with meaningful battery capacity and an inverter sized for power tool surge climbs into the low thousands. Both options are typically far less expensive than trenching a new electrical service run of any real distance from the main house, though the exact comparison depends heavily on the specific distance and local labor costs for trenching work.
Permitting Considerations
A small, standalone off-grid solar setup for a garage or shed — with no connection to the grid — often falls outside the formal building permit and utility interconnection requirements that apply to a grid-tied home system, though local rules vary and it’s worth confirming with your local building department, especially for a larger installation. If you instead run a new circuit from your home’s electrical panel to power the structure, that circuit is subject to standard electrical permitting requirements regardless of whether solar is also involved.
FAQ
Do I need a permit for a small solar setup on my shed? Often not, if it’s a small, standalone off-grid system with no grid connection, but requirements vary by jurisdiction — check with your local building department before installing, particularly for anything beyond a very small lighting-only setup.
Can I run power tools off a small shed solar system? Yes, but the inverter needs to be sized for the startup surge of the specific tools you plan to use, not just their running wattage — a table saw or air compressor can require several times its running wattage to start.
Is it cheaper to trench a circuit from my house or install standalone solar? It depends heavily on distance. For a garage or shed close to the house, trenching a circuit is often cost-competitive or cheaper. For longer distances, a standalone solar setup frequently becomes the more economical option.
Can I add solar to a garage that’s already wired to my home’s electrical panel? Yes — in that case, solar panels on the garage roof can be tied into your home’s grid-tied solar system (if you have one) or into the garage’s existing circuit to offset its electricity use, rather than requiring a separate standalone system.