Home battery guide
Whole-Home Vs Critical-Loads Backup
How to compare a whole-home battery design with a smaller critical-loads backup panel.
What to know before you compare installers
- Critical-loads backup protects essentials with a narrower and often more predictable scope.
- Whole-home backup may feel simpler but needs careful large-load planning.
- Do not compare quotes unless both designs protect the same loads.
Critical loads can be the practical path
A critical-loads design focuses backup power on selected circuits such as refrigeration, internet, lighting, and medical equipment.
This can reduce battery size and complexity, but it requires clear agreement on what is and is not protected.
Use this when reviewing quotes
- Choose essential circuits before requesting quotes.
- Ask whether a backup subpanel is included.
- Ask how protected circuits can be changed later.
Whole-home backup needs more scrutiny
A whole-home proposal should explain large-load behavior, battery capacity, inverter output, and whether load management is required.
Do not compare whole-home and critical-loads quotes as if they cover the same job.
Use this when reviewing quotes
- Ask which loads are excluded or managed.
- Ask what happens if HVAC starts during an outage.
- Ask if the system is designed for comfort, essentials, or both.
Use the same outage scenario for every quote
Give each installer the same outage scenario: expected outage length, must-run loads, existing solar status, and whether you want solar recharge during a grid outage.
This makes the proposals easier to compare and reduces the chance that one quote looks cheaper only because it backs up fewer loads.
Use this when reviewing quotes
- Use the same load list for every installer.
- Ask for assumptions in writing.
- Compare scope before comparing price.
Official references
Related comparisons
Use these short comparisons to challenge assumptions before talking with installers.