1. Which circuits matter?
Refrigerators, freezers, lights, internet, garage doors, medical equipment, security, and selected outlets often come first.
Backup power planning
Critical Loads Kits Start With What Must Stay On
A critical-loads kit is a focused backup-power plan. Instead of pretending the battery should run everything, it protects the circuits that matter most: refrigeration, lights, internet, medical equipment, pumps, garage access, controls, and selected outlets.
The blackout question
What Actually Matters During an Outage?
Backup design gets stronger when the homeowner separates essentials from conveniences.
During an outage, the goal is usually not to live exactly as if the grid were working. The smarter goal is to keep food cold, lights on, communications working, selected outlets available, medical equipment protected, and key pumps or controls operating safely.
SunKits.com treats critical loads as the heart of battery backup planning. A smaller, better-focused backup system can often perform more reliably than an oversized promise to run everything.
Critical-load checklist
Questions Before Building a Backup Panel
A critical-loads kit should be designed around real circuits, realistic runtime, and safe transfer equipment.
2. What should stay off?
EV chargers, ovens, electric heaters, dryers, pool heaters, and large HVAC loads can drain batteries quickly.
3. How many hours?
A four-hour peak-rate plan, an overnight blackout plan, and a multi-day resilience plan are different designs.
4. How much surge?
Refrigerators, freezers, garage doors, pumps, and compressors may need startup power beyond their running wattage.
5. How will circuits transfer?
Backup loads must be safely separated, transferred, controlled, or managed according to the equipment and code path.
6. Where will equipment go?
Batteries, inverters, panels, disconnects, and working space require careful location review before installation.
Critical Loads Still Require Code-Compliant Electrical Work
A critical-loads kit may involve a backup-load panel, transfer equipment, hybrid inverter, batteries, breakers, disconnects, labels, grounding, working clearances, and utility interconnection rules.
SunKits.com is educational. Backup-power systems require proper design, permitting, utility approval where applicable, licensed installation, inspection, fire-code review, and code compliance.
Read the Safety Page
Common mistake
Putting Too Much on Backup
The fastest way to disappoint a battery is to ask it to run every load in the house.
Backup planning should be honest. Some circuits are essential. Some are convenient. Some are battery killers. If a homeowner wants longer runtime, the first design move is often not a bigger battery. It is a better load list.
A critical-loads kit protects the important circuits while keeping large, nonessential loads from draining the system.
Load categories
What Belongs on a Critical-Loads Kit?
The final list depends on the property, but these categories are common starting points.
Food & Refrigeration
Refrigerators and freezers are common backup priorities because food loss can happen quickly during longer outages.
Light & Communication
Selected lights, internet, phones, routers, and small outlets can keep the home functional and informed.
Health & Safety
Medical equipment, security systems, garage access, and selected safety circuits may deserve priority review.
Water & Controls
Well pumps, booster pumps, sump pumps, gates, controls, and pressure systems require careful surge and runtime review.
Equipment pieces
What Goes Into a Critical-Loads Kit?
A critical-loads kit is both an equipment package and a circuit strategy.
A practical design may include a hybrid inverter, battery bank, backup-load panel, selected circuit relocation, transfer equipment, monitoring, solar input, disconnects, breakers, wire, conduit, labels, placards, permit drawings, and inspection documents.
Common Critical-Loads Components
- Hybrid inverter or backup-capable inverter
- Battery storage sized for realistic runtime
- Backup-load or critical-load panel
- Selected circuit relocation or load management
- Transfer equipment or approved backup architecture
- Disconnects, breakers, conduit, wire, and labels
- Solar recharge or future solar readiness
- Permit drawings and inspection documents
Planning path
How to Build a Better Critical-Loads List
Walk the House
Identify refrigerators, freezers, internet equipment, lights, garage doors, medical devices, pumps, controls, and selected outlets.
Mark the Must-Haves
Separate essential circuits from nice-to-have circuits. This keeps the battery focused on what matters.
Remove Battery Killers
EV chargers, electric heaters, ovens, dryers, pool heaters, and large loads need special review before backup is promised.
Check Surge Loads
Pumps, compressors, freezers, refrigerators, and garage doors may require startup power beyond their normal running load.
Pick a Runtime Target
Decide whether the system should cover a few peak-rate hours, overnight backup, or longer outage resilience.
Design the Panel
A licensed professional should determine how circuits, transfer equipment, batteries, inverters, labels, and permits fit together.
What Critical-Loads Kits Can Do Well
A properly planned critical-loads kit can make backup power more realistic, useful, and durable.
- Keep food refrigeration and key lights working
- Support internet, phones, and selected outlets
- Protect medical or safety-related equipment where properly designed
- Extend battery runtime by excluding nonessential loads
- Make outage expectations clearer for the homeowner
- Support solar recharge and battery management during longer events
What Critical-Loads Kits Should Not Promise Blindly
Critical-load backup is strong because it is focused. It should not be sold as unlimited whole-home power.
- Do not assume the battery can run every circuit.
- Do not put large heat loads on backup without separate review.
- Do not ignore startup surge from pumps and compressors.
- Do not skip transfer equipment, labels, disconnects, or inspection.
- Do not treat backup power as a substitute for evacuation or emergency planning.
Manga lesson
The Load Monster Tries to Sneak Into the Backup Panel
Refrigerator, Internet Router, and Medical Outlet are invited to the battery party. Then Load Monster shows up dressed as an EV charger. Solar Sensei checks the guest list.
Solar Sensei Says:
“Backup power is not a buffet. It is a lifeboat. Choose the passengers before the storm arrives.”
See Manga Episodes
ABC Solar help
Choose the Critical Loads Before Buying the Battery
Identify the must-have circuits, runtime target, surge loads, battery size, inverter limits, equipment location, and permit path before selecting a kit.