Off-grid solar in Idaho
In Idaho's darkest month, December, panels tilted toward the sun get about 2.4 peak sun hours a day, from 1.7 to 3.0 depending on where you are. Sized for that, a typical off-grid home needs about 18 panels and 4 batteries; a cabin, 4 panels and 1 battery. Flat panels, like on a van roof, get 45% less that month.
Answer a few taps in a guide and every page like this shows the numbers for your own setup. Start
Every setup, sized for Idaho
Each guide's usual answers, with Idaho's December sun. Tap one to change the answers to yours.
| Setup | Panels | Batteries | About |
|---|---|---|---|
| Off-grid home | 18 × 410 W | 4 | $10,000 – $12,500 |
| Backup for my house | 4 × 410 W | 2 | $9,000 – $11,500 |
| Tiny house | 8 × 410 W | 2 | $6,000 – $7,500 |
| Cabin or shed | 4 × 410 W | 1 | $4,000 – $5,000 |
| RV, bus or skoolie | 8 × 410 W | 2 | $6,000 – $7,500 |
| Van | 4 × 200 W | 3 | $6,000 – $7,500 |
| Just emergencies or camping | 4 × 200 W | Power station | $3,500 – $4,500 |
Van and RV numbers use flat-roof sun (1.3 h) and are capped by roof space, so they lean on driving and a generator in December. Costs are the gear only.
Sun in Idaho, month by month
Tilted at latitude Flat. December gets 34% of the sun of the brightest month (6.9 h). Size for December and the rest of the year has spare.
Across Idaho
Darkest-month sun differs by place. The 7 ZIP areas range from 1.7 hours in the 838xx ZIP area to 3.0 in the 833xx ZIP area. That's 76% more panel output for the same panels.
Common questions
How many solar panels do I need to live off grid in Idaho?
Sized for Idaho's darkest month (December, about 2.4 peak sun hours on tilted panels), a typical off-grid home needs about 18 panels (410 W each) and 4 server-rack batteries; a cabin about 4 panels and 1 battery. Your own loads change this; the guides size it for you.
How many peak sun hours does Idaho get in winter?
About 2.4 a day in December on panels tilted at latitude, and 1.3 on flat panels (NASA POWER, at the state's center of population), ranging from 1.7 in the 838xx ZIP area to 3.0 in the 833xx ZIP area.
Does off-grid solar work in Idaho in winter?
Yes, if it's sized for December: that month gets about 34% of the sun of the brightest month, so a system sized for December has plenty the rest of the year.
Data: NASA Langley Research Center POWER Project, long-term monthly averages at Idaho's 2020 Census center of population and at each 3-digit ZIP area. Method and downloads.