How many batteries do I need?

It depends on critical-load energy, peak and surge power, desired hours, usable depth of discharge and inverter efficiency. The planner produces a capacity and power range, not a brand count.

Can a battery run central air conditioning?

Sometimes, but HVAC has substantial running and starting loads. Equipment specifications, service configuration and installer design must confirm it.

Will solar recharge a battery during an outage?

Only if the installed system is designed and configured for islanded solar charging. Weather, array output and the chosen equipment constrain recharge.

Resilience planning

Solar panels vs. solar plus battery in the DMV

A battery is an energy and power decision. Renovessa estimates both from the loads you choose, their duty cycles and surge needs, then labels the result as planning guidance pending an installer load review.

Editorial owner: Renovessa Research & ProductSubstantively reviewed September 2, 2026

Engineering limitations reviewed at planning-model level; site design remains installer responsibility.

Start with what must stay on

Refrigeration, internet, lighting, selected outlets, medical equipment, pumps and HVAC have different continuous and starting-power needs. The estimator lets you edit each load rather than assuming every home has the same circuit list.

Energy capacity answers how long selected loads may run
Power rating answers which loads can operate at the same time
Surge capability matters for motors and compressors
Reserve, depth of discharge and inverter losses reduce nameplate capacity

Backup duration is a range, not a promise

Actual duration changes with weather, thermostat settings, appliance cycling, battery state of charge, degradation and whether solar can recharge during the outage. Full-home backup also requires service-equipment and transfer-design review.

Solar-only and battery economics stay separate

A battery can provide outage resilience even when it lengthens simple financial payback. Time-of-use or export rules may affect bill value, but those calculations require a confirmed tariff. Renovessa does not invent a battery price or savings value when approved source data are missing.

Frequently asked questions

How many batteries do I need?: It depends on critical-load energy, peak and surge power, desired hours, usable depth of discharge and inverter efficiency. The planner produces a capacity and power range, not a brand count.
Can a battery run central air conditioning?: Sometimes, but HVAC has substantial running and starting loads. Equipment specifications, service configuration and installer design must confirm it.
Will solar recharge a battery during an outage?: Only if the installed system is designed and configured for islanded solar charging. Weather, array output and the chosen equipment constrain recharge.

Sources, review and limitations

Renovessa uses primary government, regulator, utility and model-provider sources. Links below are the evidence pack for this guide; account rules, funding and eligibility still require confirmation at decision time.

U.S. Department of Energy — homeowner's guide to going solar
Federal consumer guidance on roof, quotes, ownership and project review.

Substantive change: Added critical-load, power, surge and usable-capacity decision framework.
Update policy: Review dates change only after the evidence or explanation is substantively checked—not automatically.

Educational planning information only. It is not a contractor proposal, engineering approval, utility determination, legal advice, tax advice or financial advice. Read the calculator methodology.