How this is calculated
Every figure on the plan comes from the same handful of formulas the rest of this site uses, so a design sketched here carries into the individual calculators without the numbers moving. The plot is drawn to scale: one cell is five meters, a meter of height is a meter, and a tree is seven to eleven meters tall because that is what shades an array.
Generation. A solar array makes rated kW × peak sun hours × 0.75 kilowatt-hours a day, where 0.75 is the 25 percent system-loss default carried by the solar sizing calculator: inverter, controller, wiring, heat and dirt. Two further multipliers come from where you put it. An aspect factor of 1.00 facing the equator, 0.82 east or west, 0.55 facing away. And a shading factor that falls as far as 0.30 when trees fill the three rows in front of the panels. A wind turbine makes rated kW × 24 × capacity factor, the capacity factor starting at 9 percent on open flat ground, rising to 13 on an exposed coast and collapsing to about 5 in the turbulence of trees or a roof within five cells. Micro-hydro is entered as a flat continuous output for the plot it sits on — roughly 300 W beside a river, 110 W beside a hillside stream — because the plan carries no measured head or flow.
Storage. A 10 kWh lithium bank at 80 percent depth of discharge and 90 percent round-trip efficiency delivers 7.2 kWh, which is exactly what the battery bank calculator returns. Days of autonomy is that delivered energy divided by daily consumption, and two days is the working target across this site. Park the bank more than 15 meters from the loads and the plan charges one percent of throughput for every further ten meters, capped at ten percent. The cable is drawn on the plot, and it turns red when it is too long.
Water. Roof catchment is roof area × rainfall × 0.80, the runoff and collection efficiency the catchment calculator defaults to. Demand is people × the per-person figure, plus the garden and greenhouse, minus 25 liters a person a day where a composting toilet replaces the flush. Rain is spent first, then filtered surface water, and only the remainder is pumped — which is the whole point of that ordering. Pumping costs 0.66 Wh a liter at 45 meters of lift, scaled by the depth of the water table under the plot you chose. That constant is the well pump calculator's own arithmetic: a 1,500 W pump moving 10 gallons a minute is 1,500 divided by 2,274 liters an hour.
Heat. Each building carries a winter design-day heat demand: 15 kWh for a tiny house, 30 for a small cabin, 80 for a larger house. A wood stove with a full store covers 45 kWh a day, a 1,900-liter propane tank 60, a solar hot-water panel 5. There is no degree-day model behind those figures. They are winter-day estimates, and a cold snap in a leaky building will beat all of them.
The score. The homestead score out of 100 is a re-reading of the same numbers, in six parts: power (renewable generation against load, 20), storage (to the two-day target and a little beyond, 20), water (supply, safe to drink, caught before pumped, 20), heat (covered, and covered without bought-in fuel, 15), access and robustness (a track that reaches, an inverter with surge headroom, no generator in the loop, 15) and siting (how well every array, turbine, bank and tank sits where it is, 10). Nothing in it rewards placing more kit; a tenth array moves nothing.
A worked example. Flat land, American defaults. Drop a small cabin, one solar array facing south with nothing in front of it, one battery bank, one inverter shed, one well and one wood store. The array makes 2.0 × 4.5 × 0.75 = 6.75 kWh a day. The cabin draws 3.0, the inverter idles at 0.35, and two people at ten gallons each need 76 liters, which the pump lifts from 55 meters for 61 Wh. That is 3.41 kWh a day against 6.75 made. The bank delivers 7.2 kWh, so autonomy lands just past two days. Heat is covered half again over. The installed band comes out at $46,233 to $106,189, most of it the cabin itself.
What the placement rules teach
The rules that refuse a placement are the short list of things that are physically impossible. Nothing goes in the water. Nothing overlaps a building. Micro-hydro has to touch running water, which is why the lake plot turns it down: still water has no head, and a turbine needs falling water rather than deep water.
Everything else is allowed and then priced, because that is how a real site works. Put the array under the trees and it keeps generating, just badly. Turn it north and it loses about 45 percent. Stand the turbine beside the cabin and the roof's wake takes 40 percent off a machine that was already the weakest generator on the plot. Push the batteries out to the far fence and you buy the cable twice. Put the gravity tank on the low ground of a hillside plot and it holds water perfectly well while delivering no pressure at all, because pressure is head: one meter of fall is 0.098 bar, or 1.42 psi. On the hillside plot the tank is drawn at its true height, so you can see the fall you are buying.
Two more rules catch the mistakes that end designs rather than degrade them. Surface water is not supply until a filtration and ultraviolet unit is on the plan, so a river plot with no filter still reads as short. And an access track has to actually connect an edge of the land to a building — a track laid as a disconnected fragment gets flagged and drawn gray, because everything you own arrives along it, including the array, the tank and the drilling rig.
The time-of-day buttons above the plot change nothing in the numbers. They show what the numbers mean: at dusk the array stops and the bank takes over, at three in the morning the windows are lit only if the bank can carry one night, and on the third night of a sunless spell they stay lit only if the plan carries three days of autonomy — a day more than the two-day target this site works to.
Quick answers
How much land do you need to go off-grid?
Less than most people assume for the system itself. This plot is 2.4 acres and a full setup fills under a tenth of it. Land is bought for access, water, sun and firewood.
Where should the solar array go on the plot?
Facing the equator, with nothing tall in the three rows in front of it, and close to the battery bank. Turning it east or west costs about 18 percent; turning it away costs roughly 45.
Do you still need a well if there is a river on the land?
River water is raw water, and it only counts as supply here once filtration and ultraviolet treatment are in place. A well keeps running when the river is frozen, low or fouled upstream — and a river plot makes that well shallow and cheap.
How far can the battery bank be from the house?
Keep it inside about 15 meters of the loads. Past that the plan charges one percent of throughput for every further ten meters. The cure is moving the batteries rather than buying thicker cable.
Can micro-hydro run off a lake?
No. A turbine needs falling water and a lake has no head. Only the river and hillside plots will take one.
How many days of battery should an off-grid design carry?
Two, on 80 percent depth of discharge and 90 percent round-trip efficiency. A 10 kWh bank delivers about 7.2 kWh, which carries a 3.4 kWh-a-day cabin for a little over two days with no sun.
Go deeper
This planner is a sketch pad; the sizing happens in the dedicated tools. Take the array figure to the off-grid solar sizing calculator and the storage figure to the battery bank calculator. Build the load list properly with can I run my house off-grid and the appliance wattage chart, which is where the surge numbers that size an inverter come from. For water, the rain catchment calculator sizes roof and tank, and can you run a well pump off-grid turns a pump's plate into the start-up surge your inverter has to clear. Every piece on the plot links to its own calculator in the panel beside the plan.
Cost bands are indicative installed prices, deliberately wide, and are shown in the local symbol without a separate regional table — European installed prices sit in a similar range, with value-added tax treatment varying by country.