This is usually framed as a price comparison, which is why so many households buy the cheaper option and then discover the part nobody priced: someone has to be home, awake, and physically able to run it, every time.
Who this helps
A homeowner who has decided backup power is worth having and is weighing a permanently installed system against equipment someone sets up each time.
When to read it
Read this before you price anything. Choosing an operating model your household cannot sustain is the expensive mistake here.
What you can decide afterwards
Whether this household needs equipment that operates without anyone present, or can rely on equipment a person sets up and runs.
Quick answer
The deciding question is not price; it is who has to be present. A permanently installed system starts and transfers on its own whether or not anyone is home or awake. A portable arrangement does nothing until a person places it, starts it, and keeps refuelling it for the length of the outage. Work out who that person would be at three in the morning during the storm that caused the outage, and whether they will reliably be there.
What this chapter can help you determine
Which operating model this household can actually sustain during the outages it actually gets — not which machine is better in the abstract.
How each arrangement behaves when the power fails and nobody has done anything yet.
What each demands of a person over a long outage.
Which parts of each are owner work and which are professional work.
Who operates the system when the power fails?
Nobody has to be present
A permanently installed standby system with automatic transfer equipment starts and transfers on its own, whether or not the household is home or awake.
This points here when:
The house is regularly empty, or empty at unpredictable times.
Damage-prevention equipment such as a sump or well pump must not stop.
Nobody in the household could safely set up equipment outdoors in bad weather at night.
Outages here start during storms, when going outside is the least appealing.
If this is the wrong call: Paying for automatic operation the household did not need, plus the ongoing service and fuel commitments that come with permanently installed equipment.
A capable person will always be present
A portable arrangement is placed, started, and connected by a person each time, and refuelled by that person for as long as the outage lasts.
This points here when:
Someone is reliably home, physically able, and willing to do this at any hour.
Outages here are short enough that refuelling is not the dominant problem.
The loads that matter can be reached without connecting to the house wiring.
The household accepts that nothing happens until a person acts.
If this is the wrong call: The outage arrives when the capable person is away, ill, or travelling — which is exactly when an unattended house is most exposed.
The answer is genuinely mixed
Some risks need automatic operation and others do not, so the household is really deciding what must be covered automatically and what can wait for a person.
This points here when:
A pump or heat source must not stop, but most other loads can.
The household is occupied most of the time but not all of it.
Budget forces a choice about which risks get automatic coverage.
If this is the wrong call: Splitting the difference without deciding which loads are in which group, and ending up with equipment that covers neither case properly.
What you probably already know
Whether someone is normally home during the day.
Whether anyone in the household has run a portable generator before.
Where equipment could be stored.
How long the household is prepared to run on partial power.
What is commonly still unknown at this point
How much fuel a portable arrangement consumes over a multi-day outage, and whether fuel would be obtainable locally at that time.
Whether the loads that matter can be reached at all without work on the house's electrical system.
Whether a permanently installed system can be sited at this property.
What either arrangement would require of the existing electrical service.
Information to gather
Who is realistically at the property across a week, including nights.
Whether anyone in the household could not carry out outdoor equipment setup.
Where fuel would come from during a widespread outage, given that fuel stations need power too.
Which equipment must keep running unattended, listed by room.
Whether the property has a storage location that is dry, ventilated, and away from living space.
Questions to ask
For a generator contractor: at this property, what would automatic operation require that manual operation would not?
For a generator contractor: which parts of each arrangement are owner-operated, and which need a professional every time?
For an electrician: what would be required to power the specific loads that matter, under each arrangement?
When this does not apply
Nobody has established whether backup power is warranted at all.
The comparison is between combustion and stored energy rather than between operating models.
The property already has a permanently installed system.
What would change the decision
Occupancy changes, or the person who would operate a portable arrangement is no longer reliably present.
Outages here start lasting long enough that refuelling becomes the dominant problem.
A load that must not stop — a pump, a heat source — is added.
A professional finds the loads that matter cannot be reached without work on the house's electrical system.
What requires a qualified professional
Connecting any generator to a home's electrical system is professional work, governed by transfer equipment requirements. This handbook does not describe how it is done and no homeowner should attempt it.
Whether a portable arrangement can serve a particular load safely at a particular property is a determination for a qualified electrician, not a web page.
What this page cannot determine
Whether a portable arrangement is adequate for this property.
What size or capacity either arrangement would need.
Whether a permanently installed system can be sited here.
Deliberately out of scope here:
Recommending a size, model, or manufacturer.
Any instruction for connecting, transferring, or wiring equipment.
Whether a portable arrangement at this property is safe or permitted, which is a determination for a qualified professional and the local authority.
Bottom line
If the house must stay covered when nobody is home or able, the operating model decides this, and price is a secondary question. If someone capable is always present and outages here are short, a manual arrangement is a legitimate answer.
Safety-sensitive content. Last reviewed .
What to do next
Do this chapter's work on paper: Home load priority worksheet. Turn a vague sense of what matters into a written, prioritised list plus an explicit inventory of what you still have to look up.
The next decision is Generator or battery backup? — Which failure mode this household cares about: the flicker and the short interruption, or the multi-day event where replenishment decides everything.
Should I get a home backup generator? — Whether this household should spend further time and money investigating backup power, or resolve something else first.
the approval tracks a permanent installation brings with it — Permanently installed equipment is what puts a project onto a permit and inspection track in the first place, so the approvals are part of what you are choosing between here rather than paperwork that appears later.
the scopes that separate these two on cost — Most of the distance between the two options is installation scope rather than the machine, and that chapter names the scopes individually so you can judge which ones this property would actually incur.