Power · Emberline

Power is where people spend the most and plan the least — sizing for the house they had, not the crisis they’re planning for.

The move is to sort every load into what must never stop, what’s merely useful, and what can simply wait — then size solar, battery and a fuel backup around only the first pile. Plan for the dark week not the sunny average, for the start-up surge not just the running load, and keep cooking on its own fuel entirely.

The shape of the problem

You can't power the whole house. You don't need to.

The instinct is to size a system that runs everything the grid used to — and that way lies a battery bank the size of a wardrobe and a bill to match. The clear thought is the opposite: most of what a house draws doesn’t matter in a crisis, and a handful of things matter enormously. Power the handful properly and let the rest wait.

So the first job isn’t sizing a system. It’s sorting every load into three honest piles.

Must never stoplife-critical

A medical fridge if someone needs one, a little light, a way to charge the phone and radio, the water pump. Small in watts, absolute in need.

Genuinely usefulflex it

Fans in the heat, a laptop, tools now and then. Run them when the sun’s been generous; ease off when it hasn’t.

Can simply waitdrop it

Water heating, air-conditioning, the iron. Comforts the grid made thoughtless. In a hard month they wait — and that decision is what keeps the system affordable.

Must never stoplife-critical

Genuinely usefulflex it

Can simply waitdrop it

Most of what a house draws can wait — size for the small critical slice.

What you’re really planning for

The dark, still week — not the sunny average.

Solar is easy in June. The plan is really about the cloudy stretch in the cold months when the panels barely wake.

Size for the good average and a run of dull days will drain you flat with the fridge still needing cold. So you design for the bad week, not the yearly mean — a deliberately pessimistic sun figure — with enough battery to ride several poor days, and a fuel-burning backup for the stretch solar alone can’t carry. Sun does the daily work; the battery bridges the nights and dull days; the generator is the seatbelt you hope never to need.

It’s not the running load that trips a system. It’s the starting load.

The counter-intuitive one

It’s not the running load that trips a system. It’s the starting load.

Here is the trap that catches almost everyone. A pump might draw a few hundred watts once it’s running — but at the instant it starts, it can pull three times that for a second or two. A fridge compressor, a motor, a power tool: all of them surge on start-up.

So a system sized only for the steady, running load can be perfectly adequate on paper and still stumble the moment two motors kick in at once — the inverter trips, the lights flicker, the plan fails at 6 a.m. The fix isn’t more solar; it’s headroom: an inverter rated to pass the surge, and the discipline not to start everything together. Plan for the spike, not just the average, or the average never gets its chance.

The load that changes everything

If a medicine needs cold, that fridge sizes the whole battery.

One declared need can reshape the entire power plan: a household member whose medicine — insulin, most commonly — must stay refrigerated.

A cold-chain fridge is the one load with true, non-negotiable autonomy: it cannot go dark for even a day, through every cloudy stretch and every night, or the medicine spoils and the emergency is immediate. So it sits alone at the very top of the “must never stop” pile, and the battery is sized around it first. If your household has this need, declare it early and loudly — it changes the numbers next door more than anything else on the page. If it doesn’t, the battery can be a good deal smaller.

05The energy that shouldn’t touch the batteryCooking is its own fuel system — keep it that way.Read more

The single biggest energy demand in most homes is heat for cooking, and the worst possible way to meet it off-grid is electricity. Making heat from your hard-won battery drains it faster than anything else you could do. So cooking is planned as a separate stream, deliberately not on the solar system at all.

The main fuelLPG in rotation

Gas cylinders are clean, efficient and storable — a rotating stock of them is the everyday cooking answer, sized to a year and refilled as they empty.

The grid-down backupwood · biomass

When the cylinders run low and none can be bought, a wood or biomass stove keeps the kitchen alive on fuel you can gather. The fallback that never runs out.

The last resortelectric induction

A small induction plate on the battery — for a quick cup, an emergency, never the daily load. Present as a backup, used with restraint.

The principle is the same one that runs through this whole system: solve heat another way, and never spend a precious watt warming things — whether it’s the cooking pot, the water heater, or the room.

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—Every step of the chain leaks a little.

Panel to battery to inverter to appliance — each conversion loses a slice, so a system that must deliver a certain amount has to generate noticeably more. Size up for the losses, or fall short in practice while looking fine on paper.

—Every problem solved by hand lightens this room.

Lift water by hand or gravity and the pump leaves your power budget. Cook on gas and the hotplate leaves too. Power isn’t only generated — it’s saved, and the cheapest watt is the one you never needed.

—Batteries hate two things: heat, and being run flat.

Kept cool and never drained to empty, a good battery lasts for years; abused, it dies in one. Leave headroom so you rarely touch the bottom, and it repays you for the whole year and beyond.

How it ties to everything else

Power is the system everything else plugs into.

Water

The pump that lifts your water is often the single biggest critical load — and its start-up surge sizes the inverter. Solve some by hand or gravity and this whole system shrinks.

Medical

A cold-chain medicine is the one load that must never stop — it sits at the very top of the pile and sizes the battery first.

Air & Signal

Every powered thing in every other system lands here — an air purifier, the radios and phone charging all draw on this budget and must be counted in.

Transport

A generator and a vehicle can share one fuel store — and an EV shifts its whole load onto the battery. Plan the fuel and the charge as one.

You’ve sorted the loads. Let Emberline size the system.

Tell it what must stay on and for how long, whether any medicine needs cold, and where you are — and it sizes the panels, battery, inverter and backup, then hands you a purchase plan and a line-item cost.

Fill the Power section →← The 13 systems