How Much Can You Save With Solar Panels in Hawaiʻi?

On Oʻahu, every kilowatt-hour of solar you use at home saves you 48.6 to 52.3 cents, Hawaiian Electric's residential rate from November 1, 2026, while daytime power you export earns just 13.5 cents. An 8 kW system in Honolulu makes about 12,960 kWh a year, worth roughly $3,200 to $5,800 a year depending on how much you use yourself.

That's the honest answer, and it's why two neighbors with identical panels can save very different amounts. This guide walks through the math the way we do it at the kitchen table: what your solar produces, what each kilowatt-hour is worth under today's Hawaiian Electric programs, how a battery and BYOD Plus change the picture, and what your bill should look like afterward. Every number links to its source.

How much do solar panels save? The short version

How to calculate your solar savings

The U.S. Department of Energy breaks solar savings into four pieces: how much electricity your roof can produce, how much you use, how you pay for the system, and which incentives you get (Department of Energy). EnergySage puts it in one line: your savings are what you would have paid for electricity minus what you pay for solar (EnergySage).

On the mainland, that math is simple because many utilities credit exported power close to the retail rate. On Oʻahu it isn't, so we add one more step. Your yearly savings are roughly:

• Solar you use yourself × the retail rate you would have paid (48.6 to 52.3 cents), plus
• Solar you export × the export credit for that time of day (13.5 cents in daytime, 32.9 cents in the evening peak), minus
• What you pay for the system, spread over its life, after incentives.

That first line is where most of the money is. A kilowatt-hour you use at home is worth more than three times one you export at midday.

What makes Oʻahu different: export credits vs retail rates

This is the part most national guides skip. EnergySage's state-by-state savings estimates assume your solar covers 100% of your needs at the full retail rate (EnergySage). Under Hawaiian Electric's Smart Renewable Energy Export program, that isn't how you're paid. Exports earn time-of-day credits that are locked for the first seven years of a new agreement, and the rates are updated every three years (Hawaiian Electric).

The gap between buying and selling has widened. Oʻahu homes paid an average of 40.54 cents per kWh in 2025 (Hawaiian Electric), and the standard residential rate from November 1, 2026 is 48.6 to 52.3 cents (Hawaiian Electric). The daytime export credit is still 13.5 cents. So on Oʻahu, the question isn't just how many panels you have. It's how much of their output you use at home. Our guide to the Hawaii electricity cost explains the current rates in detail.

How much can an 8 kW system save on Oʻahu? Three examples

EnergySage reports that the average Honolulu system is about 8 kW (EnergySage). NREL's PVWatts calculator estimates an 8 kW, south-facing roof system in Honolulu at about 12,960 kWh a year, or roughly 1,080 kWh a month, with a likely range of 12,573 to 13,351 kWh (NREL PVWatts).

Here's what that output is worth at three levels of self-use. Assumptions: November 2026 Oʻahu rates, avoided grid power valued at the 50.0-cent middle tier, all exports at the 13.5-cent daytime credit, and a household that uses at least as much power as the solar it keeps.

These are worked examples, not a quote. Self-use percentages vary by household; your own share comes from 12 months of bills and your daily routine. Savings can't be larger than the bill you'd otherwise pay, which is why a system should be sized to your usage.

The Department of Energy gives a real-world Hawaiʻi example: a teacher who financed solar plus storage pays $150 a month on the loan and saves $275 a month on electricity, netting $125 a month along with backup power (Department of Energy).

How much should your electric bill be with solar?

Even with solar, you stay connected to Hawaiian Electric, so you'll still get a bill. Here's what it typically includes:

• The monthly customer charge: $13.90 for single-phase residential service on Oʻahu as of November 2026 (Hawaiian Electric).
• Grid power you still buy, mostly in the evening and overnight when panels aren't producing, unless a battery covers it.
• Minus export credits for the solar you sent to the grid.

Export credits carry over month to month, but they're trued up once a year and any credits left at the end of the year expire (Hawaiian Electric). That's another reason not to oversize. A well-designed system aims to bring your bill close to the fixed charges without building up credits you'll never use.

Solar savings on Oʻahu under Smart Export and BYOD Plus

A battery is the main way to move solar from the 13.5-cent column into the 50-cent column. It stores midday production and runs your home through the evening, when you'd otherwise buy power at full price.

Hawaiian Electric's BYOD Plus program helps pay for it. It pays $400 per kW you commit to export from a new battery during a daily two-hour window, once, with no cap, and qualifying lower-income households get another $400 per kW (Hawaiian Electric). BYOD Plus works alongside Smart Renewable Energy Export, and BYOD Plus export credits don't expire (Hawaiian Electric). Committing 5 kW, for example, earns $2,000 upfront. Our BYOD Plus guide explains the commitment in plain terms.

A battery also has value that isn't on the bill: it can keep essential circuits on during an outage. Whether it pays for itself depends on your evening usage, so we model it both ways in every proposal.

What solar costs, and how that changes your savings

Savings only mean something next to the price. EnergySage puts Honolulu at $3.42 per watt installed as of November 2026, or about $27,343 for an average 8 kW system before incentives (EnergySage). Our page on what solar costs in Hawaiʻi breaks down system and battery prices with three worked examples.

Incentives in 2026:

• Hawaiʻi state tax credit: 35% of the cost, up to $5,000 for a single-family PV system, with new limits from 2027 under Act 24 (Act 24). See our Hawaii solar tax credit guide.
• Federal residential credit: ended for home systems placed in service after December 31, 2025 (IRS). A 2026 quote that subtracts 30% is out of date.
• BYOD Plus: $400 per kW committed for a new battery, as above.

How you pay matters too. With cash, you keep all the savings once the system is paid off. With a loan, your savings are the difference between the bill reduction and the loan payment. With a lease or power purchase agreement, the leasing company owns the system and claims the federal commercial credit, which may be passed to you as a lower payment (Department of Energy, SEIA).

How to save more with solar panels in Hawaiʻi

• Size from 12 months of bills. A system bigger than your usage mostly earns 13.5-cent credits that can expire.
• Move big loads to midday. Laundry, dishwashers, pool pumps, water heating and EV charging between 9 a.m. and 5 p.m. turn exports into savings.
• Pre-cool the house in the afternoon. Running AC on solar before sunset reduces evening grid use.
• Add a battery if your evenings are heavy, and use BYOD Plus to lower its cost.
• Fix the roof first if it's near the end of its life, so you don't pay to remove and reinstall panels later.
• Compare itemized quotes on price per watt, expected yearly production and the share of your usage covered.

There's a wider benefit too: petroleum fueled 64% of Hawaiʻi's electricity in 2025 (EIA), so every kilowatt-hour you make on your roof is one less made from imported oil.

Solar savings FAQ

How much do solar panels save per month on Oʻahu?

It depends mostly on how much of your solar you use yourself. In our example of an 8 kW system in Honolulu, the value works out to about $264 a month if you use 30% of the output at home, $343 at 50%, and $481 at 85% with a battery, at November 2026 Hawaiian Electric rates. Your own usage and roof set the real number.

How much should your electric bill be with solar?

With a well-sized system, your Hawaiian Electric bill usually drops to the monthly customer charge, which is $13.90 for single-phase residential service on Oʻahu as of November 2026, plus any grid power you buy at night, minus your export credits. Leftover export credits expire at the annual true-up, so oversizing doesn't pay.

Do solar panels save money without a battery in Hawaiʻi?

Yes, but less. Without a battery, everything you don't use as it's produced is exported, and on Oʻahu daytime exports earn 13.5 cents per kWh while grid power costs 48.6 to 52.3 cents. Running laundry, dishwashers, pool pumps and AC during the day raises your savings.

How does BYOD Plus change solar savings?

Hawaiian Electric's BYOD Plus pays a one-time $400 per kW you commit to export from a new battery during a daily two-hour window, and qualifying lower-income households get another $400 per kW. BYOD Plus export credits don't expire. It lowers your net battery cost, and the battery lets you use more of your own solar.

How much do solar panels save over 25 years in Honolulu?

EnergySage estimates the average Honolulu homeowner saves about $45,962 over 25 years by going solar, based on its own price and usage assumptions. Your result depends on your system price, how much solar you use yourself and future Hawaiian Electric rates.

Do solar export credits roll over in Hawaiʻi?

Month to month, yes, but not forever. Under Smart Renewable Energy Export, credits are trued up once a year and any credits left at the end of the year expire. BYOD Plus export credits are the exception and do not expire.

Sources

• Hawaiian Electric: Effective Rate Summary (Oʻahu, November 2026)
• Hawaiian Electric: Average price of electricity (2025)
• Hawaiian Electric: Smart Renewable Energy Export
• Hawaiian Electric: BYOD Plus
• NREL PVWatts Calculator (Honolulu, 8 kW, fixed roof mount, 20° tilt, south-facing, 14.08% losses)
• EnergySage: Solar panel cost and savings in Honolulu, HI (November 2026)
• EnergySage: How much do solar panels save in 2026?
• U.S. Department of Energy: Will I save money with solar energy?
• Act 24 (SB 3125 CD2)
• IRS: Residential Clean Energy Credit
• SEIA: clean energy provisions of the One Big Beautiful Bill
• EIA: Hawaii State Profile (updated June 18, 2026)

Find out what solar would save in your home

Send us 12 months of Hawaiian Electric bills and we'll show you what solar, with or without a battery, would save on your roof: expected production, how much you'd use yourself, your export credits, your state credit and BYOD Plus amounts. Alternate Energy Hawaii has installed solar on Oʻahu since 1993 with our own employee crews. Call (808) 842-5853 or request your free estimate.