Thinking about adding solar and a battery to your Kailua home? With strong sun and new electrification trends, you have real potential to cut bills and boost resilience. The details matter, because how you configure your system on Oahu changes your savings and backup benefits. In this guide, you’ll learn how export vs non-export setups work, how Time-of-Use pricing affects payback, and what to ask before you sign a contract. Let’s dive in.
Why solar works in Kailua
Kailua benefits from Oahu’s strong solar resource. In Honolulu’s climate, rooftop systems typically produce about 1,200 to 1,600 kWh per kW per year depending on roof tilt, azimuth, and shading. Your exact production depends on your roof and nearby trees or buildings. Local microclimates and trade winds can create unique shading patterns, so address-specific modeling is important.
If you plan to electrify your home with EV charging, a heat-pump water heater, or induction cooking, solar can offset more of your usage. Batteries can shift daytime solar to evening hours and help during outages, which is valuable on an island grid.
Oahu grid rules shape your choices
Hawaiian Electric moved away from legacy full-retail net metering. Today, export compensation is narrower and Time-of-Use options influence when energy is worth most to you. The Hawaii Public Utilities Commission updates these programs over time, and installers typically reference the latest tariff sheets.
The key takeaway is simple: when export credits are lower than the retail price, storing your midday solar and using it during expensive evening periods can improve savings. Your household’s hourly usage and the current tariff will drive the best setup.
Four common system pathways
Grid-tied with export
- Description: Your PV system sends surplus power to the grid and you receive compensation per the utility tariff.
- Pros: Lower equipment cost and simpler design. You need less battery capacity to handle midday surplus.
- Cons: Export credits are usually lower than retail prices. With TOU pricing, midday exports may earn less while evening purchases can be costly.
Grid-tied with export + battery
- Description: PV plus a battery that charges from solar, then serves your home during peak hours, while still exporting any additional surplus.
- Pros: Shifts energy to on-peak periods and adds backup capability if paired with the right equipment.
- Cons: You may still export at lower compensation. Smart controls are important to optimize TOU arbitrage.
Grid-tied non-export (self-supply)
- Description: The system is configured not to export. Inverter controls or hardware prevent backfeeding the grid. Excess generation is curtailed once the battery is full.
- Pros: Maximizes self-consumption and can improve savings when export credits are low and TOU peak prices are high.
- Cons: You may curtail production on very sunny days if the battery fills and loads are low.
Hybrid backup systems
- Description: Designed to provide power during outages, either to a critical-loads subpanel or to the whole home through a transfer system. Can be export or non-export in normal operation.
- Pros: Improves resilience and comfort during outages.
- Cons: Higher cost due to additional equipment and larger batteries.
TOU and export economics
Know your tariff details
Gather these items before you model savings:
- Your rate plan’s on-peak, off-peak, and shoulder prices. Confirm exact hours and whether weekends differ.
- Export credit structure and any limits.
- Fixed monthly charges and any minimum bills.
Understand your hourly usage
Your household’s load shape is the foundation. Evening-heavy use patterns benefit most from storage that shifts solar to those hours. With electrification, a heat-pump water heater, heat-pump HVAC, and EV charging can add significant kWh and change the timing. If possible, align EV charging with midday solar or use the battery to supply evening charging.
Export vs non-export tradeoffs
- If export credits are close to retail prices, exporting can be fine and batteries are primarily for backup.
- If export credits are much lower than on-peak retail prices, batteries that store midday solar for evening use often improve bill savings, even after round-trip losses.
- Batteries have efficiency losses, so you should not route every kWh through storage unless it clearly beats export value.
Model before you decide
Ask your installer to run an address-specific production model and combine it with your hourly usage. Compare bills under each scenario: export allowed, non-export, and different battery sizes. The difference in annual bills across scenarios approximates the value of the battery and your chosen configuration.
Sizing and design for Kailua roofs
Your roof matters. Tilt, azimuth, and shade from trees or nearby buildings can change production significantly. If your roof is nearing replacement in the next 5 to 10 years, consider roofing work before installing panels. Otherwise, removing and reinstalling later adds cost.
Battery siting has code and safety requirements. Location options include interior spaces, garages, or exterior placements. Each has ventilation and setback considerations. Work with installers who follow National Electrical Code and applicable energy storage standards.
Costs, incentives, and warranties
What drives cost
- PV system cost: Varies by roof complexity and equipment choice. Larger, simpler installs usually have lower per-watt pricing.
- Battery cost: Tied to usable capacity, inverter type, and whether you want whole-home backup. Lithium iron phosphate (LFP) is common for longer cycle life.
- Extras: Electrical upgrades, meter work, permitting, and a critical-loads or transfer panel if you want backup.
Incentives and financing
- Federal Residential Clean Energy Credit: A federal tax credit applies to qualifying residential solar and certain storage. Verify current rules and talk with a tax professional about eligibility.
- State and local: Hawaii incentives are limited compared to many mainland programs, though occasional utility pilots may exist.
- Financing: Solar loans or other financing can smooth cash flow and change payback timing.
Lifetime and warranties
- PV modules: Often have a 25-year power output warranty, with gradual degradation.
- Inverters: Commonly 10 to 15 years, depending on type.
- Batteries: Warranty terms vary by chemistry and cycles. LFP is favored for safety and cycle life. Ask for guaranteed capacity over time and modeled replacement timing.
Permits, interconnection, and safety
In Honolulu County, rooftop PV and batteries require building and electrical permits. Interconnection with Hawaiian Electric follows a defined process that sets export rules and system limits. Your licensed electrical contractor should file permits, coordinate inspections, and manage utility approvals.
Energy storage must follow national and local codes. That includes proper siting, labeling, and rapid shutdown for PV. Your installer should coordinate with the local authority having jurisdiction and follow fire department protocols.
Electrification and backup planning
Electrification increases your kWh usage and can shift your peak to evening. A well-sized battery helps you use daytime solar at night and reduce on-peak purchases. If you want resilience during outages, decide whether to back up critical loads only or the whole home. Backup goals often determine battery size more than economics alone.
Decision checklist
Before you speak with installers, gather:
- Last 12 months of bills and any interval data from the utility.
- Planned electrification loads and typical schedules, especially EV charging.
- Backup needs: critical loads or whole home.
- Roof age, shading, and HOA requirements.
- Tax credit eligibility and whether you plan to finance.
Questions to ask installers:
- Address-specific production and hourly output modeling.
- Bill savings under export, non-export, and multiple battery sizes with TOU assumptions.
- Interconnection steps and expected utility timeline.
- Equipment and warranty details, including battery chemistry, efficiency, and degradation.
- Whether the system supports backup, and what panels or transfer switches are included.
- Total lifecycle cost and expected replacement timing for inverters and batteries.
How to move forward with confidence
The best path for a Kailua home comes down to your usage pattern, TOU pricing, export credits, and backup goals. Export-allowed PV can be simple and effective if credits are strong or your loads are daytime-heavy. Non-export with a right-sized battery often shines when export credits are low and your peak use is in the evening. Careful modeling with your own data is the difference between a good system and a great one.
If you are buying or selling a home with existing solar and storage, understanding equipment age, warranties, interconnection status, and configuration helps you assess value and future operating costs. A clear plan will help you align upgrades with your timing, from roof work to electrification.
Ready to explore homes and make a plan around solar-readiness, backup needs, and long-term ownership costs? Start a conversation with Raymond Kang to align your real estate goals with a practical energy strategy. Schedule your consult with Unknown Company today.
FAQs
What is typical solar production for Kailua homes?
- Rooftop systems in Honolulu’s climate often produce about 1,200 to 1,600 kWh per kW per year, depending on roof tilt, orientation, and shading.
How do Time-of-Use rates affect battery value on Oahu?
- When evening on-peak prices are higher than midday prices and export credits are low, storing midday solar for evening use can increase bill savings.
Which setup is better: export or non-export in Kailua?
- It depends on your tariff and usage. If export credits are close to retail, export can work well. If credits are much lower than on-peak prices, non-export with a battery often improves savings.
What permits and approvals are required in Honolulu County?
- Rooftop PV and batteries need building and electrical permits, plus interconnection approval from Hawaiian Electric. Your licensed installer should handle submissions and inspections.
Can a battery back up my whole Kailua home?
- Yes, with the right inverter and sufficient capacity, but many homes choose a critical-loads panel to keep essentials running while managing cost.
Do federal tax credits apply to home batteries in Hawaii?
- The Residential Clean Energy Credit offers a federal tax credit for qualifying residential solar and certain storage. Confirm current rules and consult a tax professional about your eligibility.
