Buying Guide

Battery Backup vs Generator: Which Is Better for Power Outages?

Compare home battery backup systems (Tesla Powerwall, Enphase) with standby generators for power outage protection. Costs, reliability, and maintenance compared.

Battery Backup

Advantages

+Silent operation — no noise disturbance
+Zero emissions — clean energy storage
+Instant switchover (milliseconds) — no power interruption
+Pairs with solar to recharge during extended outages
+Low maintenance — no fuel, oil changes, or engine service
+Daily value through energy arbitrage and peak shaving

Disadvantages

-Higher upfront cost ($8,500-25,000 installed)
-Limited capacity — 5-27 kWh per unit
-Cannot run indefinitely without solar to recharge
-Not practical for very high-draw loads (central AC, electric heat)
-10-15 year lifespan before replacement

Best For:

Homes with solar panels (recharges during outages)
Short-to-medium outages (4-24 hours)
Noise-sensitive neighborhoods
Homeowners who want daily energy savings plus backup
Environmentally conscious households

Standby Generator

Advantages

+Can power entire home including AC and electric heat
+Runs indefinitely as long as fuel supply lasts
+Lower cost for whole-home backup ($6,000-15,000 installed)
+Proven technology with decades of track record
+Simple — fuel in, electricity out

Disadvantages

-Loud (65-75 dB) — can disturb neighbors
-Emissions — burns natural gas or propane
-Requires regular maintenance (oil changes, filter replacement)
-10-30 second transfer time — brief power interruption
-No daily value — only useful during outages
-Fuel supply can be disrupted during major storms

Best For:

Extended outages lasting days (ice storms, hurricanes)
Homes needing full power including HVAC
Properties without solar panels
Budget-conscious whole-home backup
Rural areas with frequent, prolonged outages

NuWatt's Recommendation

For New England homeowners with solar, battery backup is usually the better investment — you get daily energy savings plus outage protection. Solar keeps the battery charged during extended outages, covering most scenarios. For homes without solar, or those that need to run central AC and electric heating during multi-day outages, a generator may be more practical. Some homeowners install both: a battery for instant, silent switchover during short outages, and a generator as a last-resort backup for extended events.

Frequently Asked Questions

How long will a battery last during a power outage?

A single 13.5 kWh battery (like Tesla Powerwall 2) powers essential loads (lights, fridge, Wi-Fi, phone charging) for 10-12 hours. With solar panels recharging during the day, you can run essential loads indefinitely during good weather. Multiple batteries extend backup time proportionally. Our battery sizer tool can calculate exactly how long your specific loads would last.

Can a battery power my air conditioning?

Most batteries can start and run a mini-split AC (1-2 tons). Central AC systems draw 3-5 kW and may exceed a single battery's continuous output. The Franklin aPower with its 10 kW peak can handle larger AC units. For whole-home AC backup, you'll typically need 2-3 batteries or a generator.

How much does a whole-home generator cost vs a battery?

A 20 kW whole-home standby generator costs $6,000-15,000 installed. A single battery (13.5 kWh) costs $11,500-12,500 installed. For true whole-home backup comparable to a generator, you'd need 2-3 batteries ($23,000-37,500). Batteries cost more upfront but provide daily savings that generators don't.

Do batteries qualify for tax credits?

In 2026, the residential Section 25D clean energy tax credit has expired for homeowner-owned systems. Batteries purchased through a lease or PPA may still qualify for the 30% commercial ITC under Section 48/48E. State-level incentives may still apply depending on your location. Generators do not qualify for any energy tax credits.

What maintenance does each option require?

Batteries require virtually zero maintenance — just keep them within operating temperature range. Generators require annual oil changes, spark plug replacement, air filter changes, and weekly exercise runs. Budget $200-500/year for generator maintenance. Battery monitoring is handled automatically through the manufacturer's app.

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Battery Backup

Advantages

+Silent operation — no noise disturbance
+Zero emissions — clean energy storage
+Instant switchover (milliseconds) — no power interruption
+Pairs with solar to recharge during extended outages
+Low maintenance — no fuel, oil changes, or engine service
+Daily value through energy arbitrage and peak shaving

Disadvantages

-Higher upfront cost ($8,500-25,000 installed)
-Limited capacity — 5-27 kWh per unit
-Cannot run indefinitely without solar to recharge
-Not practical for very high-draw loads (central AC, electric heat)
-10-15 year lifespan before replacement

Best For:

Homes with solar panels (recharges during outages)
Short-to-medium outages (4-24 hours)
Noise-sensitive neighborhoods
Homeowners who want daily energy savings plus backup
Environmentally conscious households

Standby Generator

Advantages

+Can power entire home including AC and electric heat
+Runs indefinitely as long as fuel supply lasts
+Lower cost for whole-home backup ($6,000-15,000 installed)
+Proven technology with decades of track record
+Simple — fuel in, electricity out

Disadvantages

-Loud (65-75 dB) — can disturb neighbors
-Emissions — burns natural gas or propane
-Requires regular maintenance (oil changes, filter replacement)
-10-30 second transfer time — brief power interruption
-No daily value — only useful during outages
-Fuel supply can be disrupted during major storms

Best For:

Extended outages lasting days (ice storms, hurricanes)
Homes needing full power including HVAC
Properties without solar panels
Budget-conscious whole-home backup
Rural areas with frequent, prolonged outages

NuWatt's Recommendation

Frequently Asked Questions

How long will a battery last during a power outage?

Can a battery power my air conditioning?

How much does a whole-home generator cost vs a battery?

Do batteries qualify for tax credits?

What maintenance does each option require?

Update Location

Battery Backup vs Generator: Which Is Better for Power Outages?

Battery Backup

Advantages

Disadvantages

Best For:

Standby Generator

Advantages

Disadvantages

Best For:

NuWatt's Recommendation

Frequently Asked Questions

Need Help Choosing?

Battery Backup vs Generator: Which Is Better for Power Outages?

Battery Backup

Advantages

Disadvantages

Best For:

Standby Generator

Advantages

Disadvantages

Best For:

NuWatt's Recommendation

Frequently Asked Questions

Need Help Choosing?