Generator on its own
Runs constantly, mostly at part load
- Burning fuel through the night to keep a fridge cold and a router lit
- Everything it makes above what you're drawing is simply wasted
- Noise from dinnertime until morning, for you and your neighbours
- Every hour is an hour on the service clock — oil, plugs, filters
- Long stretches of light loading are hard on a diesel
Generator plus battery
Runs hard, briefly, then shuts itself off
- All that surplus output goes into the battery instead of out the exhaust
- The generator works near its rated load, where it's at its most efficient
- It stops on its own once the bank is full — no walking outside in the rain
- Silent overnight. The battery covers the small hours and nobody wakes up
- Far fewer running hours, so far less servicing and far less fuel hauled
What a night actually looks like
The battery carries the house instantly. Nothing flickers, and the generator doesn't even start.
The system starts the generator on its own, at a civilised hour if it can choose.
House loads plus a heavy charge current means the generator works near full load — the efficient end of its curve.
Bank full, generator off. The house runs silently on stored power until it needs another top-up.
With an array on the roof, the battery may refill itself and the generator never starts at all.
Worth saying first
You may not need one
With a big enough bank, plenty of New Hampshire homes ride out an ordinary outage without a generator ever starting. If you’re buying storage anyway, price the larger bank before you price a generator — it’s silent, it needs no fuel delivery, and there’s nothing to service every autumn.
If you already own one
We’ll integrate it
A whole-home standby unit and a battery work well together, and you’ve already paid for the generator. We tie it in so the bank carries the short outages silently and the generator only wakes for the long ones. No reason to replace something that works.
The cheap insurance
A portable works too
You don’t need a standby unit on a pad. We can fit a generator inlet and interlock so a portable you already own — or one you buy for a few hundred dollars — can feed the system if a stretch of weather outlasts the bank. Most people never use it. It costs little to have.
Fuel saved depends on your generator, your loads and how big a bank sits in front of it. What's consistent is the shape of it: fewer running hours at a better load point, and a quiet night. We'll work out your numbers on the walkthrough, and we integrate the unit you already own rather than selling you a replacement.
What it costs to own one
Idle isn’t free.
A generator bills you every year whether the grid fails or not — servicing, and fuel burned on a weekly test that exists purely to prove the thing still starts. A battery has none of that. Put your own numbers in.
Most whole-home units around here are 18–26 kW.
NH residential propane has been running near $3.78–3.91.
Oil, filters, plugs, battery and a load test. Published ranges run $200–600 a year.
The self-test runs 52 weeks a year, outage or not. Skipping it is how generators fail when you need them.
A couple of storms. Rural NH runs higher; a bad ice year much higher.
Set this to zero if you already have propane in the house for other things.
Weekly testing
—fuel burned proving it worksOutage fuel
—when it actually runsService & tank
—whether it runs or notGenerator, per year
———
A battery bank has no fuel, no deliveries and no weekly test. We’d still put it on an annual health check — call it $150 a year — and that is the whole of its running cost. This compares running costs only. Neither figure includes what you paid to install the thing, and both a generator and a battery bank reach the end of their life eventually. Figures are estimates built from published service ranges and propane consumption at the loads shown; your unit and your winter will differ.
Keep going
Where to next.
The calculator
What you'd save
Thirteen sliders and your own fuel bills. Most oil homes land in the thousands a year.
Run your numbers →The equipment
What we install
Storage, arrays, automatic switching, generator integration and the service work underneath.
See the systems →The part nobody audits
Green thumb
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