Master matrix

Home backup power, compared tier by tier

Engineering comparison of four tiers of home backup power, from indoor LiFePO4 batteries to 26 kW automatic standby generators. Labelled sources, published formulas and no affiliate hype.

Data labels: Manufacturer stated Calculated Planning estimate Pending verification

Which backup power tier fits my home?

Read across a row to compare one property between tiers, or down a column to see one complete system. Every tier name links to its long-form engineering guide.

Master comparison matrix: four tiers of home backup power
Parameter	Tier 1: Indoor emergency & medical	Tier 2: Essential circuits & food preservation	Tier 3: Modular home energy storage	Tier 4: Turnkey whole-house standby
Primary use case	CPAP/BiPAP, oxygen concentrators, Wi-Fi, refrigeration; no combustion indoors.	Food preservation, gas furnace blower, sump pump, selected 120 V circuits.	Multi-day quiet backup, 240 V well pump, selected central AC, solar recharging.	Hands-off restoration, multi-ton HVAC, electric ovens, dual living zones.
Representative hardware	EcoFlow DELTA Pro 3 / BLUETTI AC200L	Champion 9000W Tri-Fuel / Westinghouse 9500DF	Anker SOLIX E10 / EcoFlow DELTA Pro Ultra	Generac Guardian 22–26 kW / Kohler 20RCA
Continuous (rated) output	2,400–4,000 W pure sine wave	7,000–9,000 W (inverter models; check THD spec)	7,200–12,000 W split-phase 120/240 V (configuration-dependent)	18,000–26,000 W whole-home
Starting surge capacity Planning estimate	Up to ~8,000 W momentary (model-dependent)	9,000–11,500 W peak	10,000–20,000 W (model-dependent)	Engine-generator motor-starting capability per manufacturer data
Placement & safety	Indoors where the product listing/manual permits. No CO in normal operation; not fire-proof.	Outdoors only, at least 20 ft from doors, windows and vents, exhaust pointed away. Never in a garage. CO alarms inside.	Indoor or outdoor per manufacturer's installation manual and local code; licensed installation.	Outdoor permanent pad; clearances per manufacturer manual, NFPA 37 and the local AHJ. CO alarms inside.
Noise Planning estimate	Silent at idle; fan noise under load	Roughly 58–65 dBA (enclosed inverter)	Silent at idle; fan noise under heavy load	Roughly 65–68 dBA
Typical runtime per cycle Calculated / Planning estimate	2,048 Wh at 20 W DC CPAP: ~87.5 h. Fridge (60 W avg): ~26 h.	20-lb propane: roughly 14–18 h at 50% load	6–18 kWh: roughly 18–48 h of essentials	Natural gas: as long as utility supply holds, subject to oil-change intervals. 500-gal LP: roughly 7 days at 50% load.
Connection hardware	Direct plug-in, or inlet/transfer device installed by an electrician	30 A/50 A interlock + inlet box, installed by a licensed electrician	Smart subpanel or transfer switch, licensed installation	200 A service-entrance automatic transfer switch (ATS)
Must-have accessory	Device maker's 12 V/24 V DC CPAP adapter	HVAC soft-start kit (e.g., Micro-Air EasyStart)	Split-phase output capability for 240 V well pumps	Cold-weather kit (battery warmer, oil/breather heater as specified)
Hardware price range Planning estimate	$1,200–$2,800	$1,100–$2,200	$4,500–$9,800	$5,500–$7,500 (unit + ATS)
Install cost Planning estimate	$0 if plug-in only	$600–$1,200 (electrician, inlet + interlock)	$1,200–$2,500 (subpanel wiring, permits)	$5,000–$9,000 (gas, ATS, pad, inspection)
Core system investment Planning estimate	$1,200–$2,800	$1,700–$3,400	$5,700–$12,300	$10,500–$16,500+

Price ranges are undated illustrative planning estimates for a representative core system, not quotes. Each tier guide itemises a broader scope (optional solar, gas work, permits, accessories), so its totals differ by design. No tax credit has been deducted anywhere on this site.

Continuous output ranges from the matrix, drawn to a linear scale.

How do I size backup power for my largest motor load?

Calculate the starting surge (locked rotor amps) of your single largest motor load, typically a central air conditioner or deep well pump, then add the continuous running wattage of everything else that runs at the same time.

Resistive loads (lights, routers, space heaters, electric blankets) draw flat running wattage with essentially no starting surge.
Inductive motor loads (refrigerators, well pumps, furnace blowers, air conditioners) commonly need roughly 3× to 6× their running power for a fraction of a second to start. Planning estimate
A compressor soft-start kit can cut inrush substantially; makers cite up to about 70%. In some cases this lets a ~7.5 kW generator start a 4-ton AC that would otherwise need a much larger unit. Results depend on the compressor; see Tier 2.

Does my backup source need pure sine wave power?

Sensitive electronics, ECM furnace blowers and variable-speed appliances generally run best on low-distortion power. Follow each appliance maker's guidance; many cite total harmonic distortion (THD) limits around 3–5%.

Open-frame conventional generators can produce noticeably higher THD than inverter models, which can cause nuisance faults in some modern furnace controls.
Inverter generators and LiFePO4 power stations synthesise a sine wave; check the published THD figure for the exact model rather than assuming one.
Medical devices should be powered only as the device maker specifies, typically from pure sine wave AC or an approved DC adapter.

What does backup power really cost once it is installed?

Equipment is often only part of the bill. For permanently connected systems, labour, permits and connection hardware can account for a large share of the total. Planning estimate

Portable and modular systems connected to a panel need an exterior inlet, an interlock or transfer device and an appropriately sized cord, installed by a licensed electrician (roughly $600–$1,400).
Automatic standby systems need a service-rated transfer switch, permits, a mounting pad and gas supply verification (roughly $5,000–$9,000 in trade labour).
Plug-in power stations avoid installation costs but only power what you plug into them, unless an electrician adds an inlet or critical-load subpanel.

What do manufacturers officially state for current battery systems?

These are the figures we could tie to an official manufacturer document. They are reproduced, not measured.

Manufacturer-stated reference specifications with sources
Model	Energy per unit	Continuous AC output	Voltage	Status & source
EcoFlow DELTA Pro Ultra (inverter + 1 battery)	6,144 Wh per battery	7,200 W per inverter	120/240 V (US)	Manufacturer stated EcoFlow DELTA Pro Ultra user manual (US)
Tesla Powerwall 3	13.5 kWh	Configurable 5.8 / 7.6 / 10 / 11.5 kW	Installer-configured	Manufacturer stated Tesla Powerwall 3 installation manual — system specifications
BLUETTI AC500 + one B300S	3,072 Wh per B300S	5,000 W	120 V per single system; 240 V requires a dual-system setup	Manufacturer stated BLUETTI AC500 + B300S specifications (US)
Anker SOLIX F3800	3,840 Wh (as listed in brief)	6,000 W (as listed in brief)	Verify on official page	Pending verification Anker SOLIX F3800 product page

Anker SOLIX E10 and F3800 are different products; Reserve does not combine their specifications. Verify the exact configuration before purchase.

What safety rules apply to every tier?

Combustion engines stay outdoors. Portable generators: at least 20 ft from doors, windows and vents, exhaust pointed away, never in a garage or porch. Install battery-backed CO alarms. CDC — Carbon monoxide poisoning prevention
Batteries are not fire-proof. Use indoors only where the product listing and manual allow, within stated temperature and clearance limits.
Panel, neutral and gas work is for licensed professionals. Interlocks, transfer switches, neutral bonding changes and gas piping need permits and qualified installers.
Life-support equipment needs a plan, not a product. A 10–20 ms transfer is not a true online UPS and does not guarantee medical continuity. Agree a backup with your clinician and device maker and keep an independent contingency.

How does Reserve produce these comparisons?

Reserve is an independent reference with no affiliate links. Specifications are labelled Manufacturer stated only when tied to an official manufacturer document linked beside them. Values derived with our published formula are labelled Calculated: Runtime (hours) = Battery Wh × 0.90 usable depth of discharge × conversion efficiency (0.85 for AC inverter output, 0.95 for DC ports) ÷ continuous load (W). Broad noise, price, surge and runtime ranges are labelled Planning estimate and should be confirmed against current manuals and local quotes. We publish no hands-on test results and no ratings, because we have not run them.

Which sources is this page based on?

Figures marked Planning estimate are illustrative ranges for budgeting and comparison. They are not measured test results, quotes, or verified benchmarks. Reserve has not performed hands-on testing of the equipment named here.

Frequently asked questions

How do you calculate the generator size needed for a house?

Find the starting surge (locked rotor amps, LRA) of the single largest motor load, typically a central air conditioner compressor or well pump, and add the continuous running wattage of every other appliance that will run at the same time. A properly installed soft-start kit can substantially reduce an AC compressor's starting surge; manufacturers cite reductions of up to about 70%, but the result depends on the specific compressor.

Can you run a CPAP machine from an indoor battery power station?

Many households do, using a battery power station listed for indoor use with pure sine wave AC output or, better, the CPAP maker's DC adapter. Turning off the heated humidifier typically lowers CPAP draw from roughly 60–90 W to 15–25 W. By the Reserve runtime formula, a 2,048 Wh station runs a 20 W DC CPAP load about 87.5 hours, about 11 eight-hour nights. A power station is not a medical-grade UPS: confirm the setup with your device maker and clinician and keep an independent contingency plan.

Is a battery power station completely safe to use indoors?

A lithium iron phosphate battery station produces no carbon monoxide in normal operation, which is why it can be placed indoors when the product's listing and manual allow it. It is not fire-proof or risk-free: follow the manual's ventilation, clearance, charging and temperature limits, and never place it near combustibles or water.

Why do budgets on this matrix differ from the tier guides?

The matrix summarises a representative core system for each tier, while each tier guide itemises a fuller scope, such as optional solar, gas piping, permits, meter upgrades and cold-weather accessories. Both are planning estimates, not quotes, so the ranges are not meant to match exactly.