Start with duration, not with product
The generator-versus-battery argument is usually conducted as a product comparison, which is why it rarely resolves. The question that actually settles it is: how long do you need to keep running, and what do you need to keep running?
A BATTERY stores a fixed amount of energy. It starts instantly with no gap, makes no noise, needs no fuel and almost no maintenance, and when it is empty it is empty. On its own it is a bridge measured in hours of your critical loads.
A GENERATOR converts fuel to electricity for as long as fuel lasts. That makes it the straightforward answer to a long outage, and it brings noise, maintenance, a fuel supply to manage, and a delay between the power going out and the generator picking up.
The pairing that changes the arithmetic is BATTERY PLUS SOLAR. A battery that recharges every day the sun is up stops being a bridge and becomes something that can carry a multi-day outage indefinitely — which is exactly the profile of a planned de-energisation. That is why a battery quoted for a fire-season use case without solar behind it deserves a question, and why the honest answer for many mountain properties is a combination rather than a single product.
The well pump, which sizes everything
If you are on a well — and a great many properties up here are — this is the most important technical fact on the page.
An electric motor draws substantially more current starting than it does running. A backup system sized against a pump's running figure will simply fail to start it, and the failure mode is not subtle: you get a house with lights, a working fridge, and no water. That is not a functioning house for more than about a day, and it is a discovery people make during the outage rather than during the planning.
So on a well property the pump is what sizes the system, and it belongs in the calculation from the beginning. There are ways to make this easier — soft-start devices that reduce the starting demand are a real and often cost-effective option — but they are a design decision to make deliberately, not something to hope for afterwards. The same applies to septic pumps where they exist.
What actually needs backing up
The instinct is to back up the house. The economics strongly favour backing up a list, and the list is usually shorter than people expect once it is written down.
- MEDICAL EQUIPMENT, if it applies — this outranks everything else and changes the whole conversation
- WATER — the well pump, and any septic or booster pump. First on the list for most mountain properties
- REFRIGERATION, which is cheap to carry and expensive to lose
- HEATING, or enough of it. Worth being honest about what you actually need rather than backing up whole-house comfort
- LIGHTING AND COMMUNICATIONS — a small load that makes an enormous difference to how an outage feels
- Anything else you would genuinely miss on day three, which is a shorter list than the one you would write on day one
Those circuits go on a CRITICAL LOADS PANEL — a sub-panel fed by the backup system during an outage. It is simple, permanent and inexpensive relative to what it saves, because it lets the backup system be sized for what matters. The alternative is doing that selection in software with a smart panel, which buys flexibility to change your mind later at a real premium.
The two things that kill people
This section is not balanced comparison. It is instruction.
CARBON MONOXIDE. A generator never runs indoors. Never in a garage, including with the door open. Never close enough to a window, door or vent that exhaust can find its way inside. This kills people every storm season, including people who were careful about everything else, and it kills them while they sleep.
BACKFEEDING. Do not connect a portable generator to the house through an outlet. It energises the utility conductors outside your property, where line workers are trying to restore your power, and it bypasses the protection in your panel. The correct answer is a properly installed transfer switch or a listed interlock. If you own a portable generator and have been powering the house any other way, fix that before the next outage rather than after it.
The practical differences that decide it
- NOISE — a standby generator runs for the whole outage and also runs a periodic self-test on a schedule. Siting relative to bedrooms and neighbours matters, and local noise rules vary by jurisdiction
- FUEL — propane suits many mountain properties because the tank is already there and stores indefinitely. Gasoline portables need refuelling during precisely the conditions that make driving unattractive
- MAINTENANCE — generators need exercising and servicing to be there when needed. An unmaintained generator is a decoration. Batteries need essentially none
- TRANSFER TIME — a battery covers the gap seamlessly; a generator takes a moment to start and transfer, which matters for anything that objects to losing power briefly
- EVERYDAY VALUE — a battery can shift consumption away from expensive periods under time-of-use rates. A generator is insurance that sits idle between outages
- DEGRADATION — batteries lose capacity over their life, which is worth understanding when sizing for a need ten years out
Where the hybrid earns its place
Battery plus generator is more expensive than either alone, and in the mountains it is often the honest recommendation rather than an upsell.
The battery handles the instant, silent, everyday case: short outages, the transfer gap, and rate shifting when the power is on. The generator handles the case the battery cannot — a multi-day outage in poor weather, when solar is not recharging much and the stored energy runs down. Each covers the other's weakness, and where outages are genuinely long and genuinely frequent, that is worth what it costs.
On the trade boundaries: solar, battery and the electrical side of a generator are all in-house work for us on a C-10. The one exception is the gas line to a generator, where we bring in a licensed sub. On the battery side there is no fuel and no second trade at all, which is a genuine practical simplicity worth weighing alongside everything else.