Find answers to the most common questions about going solar in Hawaii. Can't find what you need? Contact us or call (808) 842-5853.
A typical residential solar PV system in Hawaii costs between $20,000 and $40,000 before incentives, depending on system size and equipment choices. Most Oahu homes install 8–14 kW systems. After the Hawaii state tax credit (35% up to $5,000), the net cost is significantly reduced. Battery storage (Tesla Powerwall 3) adds roughly $12,000–$16,000 per unit.
Use our free solar calculator to get a personalized estimate based on your electric bill in about 60 seconds.
The 30% federal Investment Tax Credit (ITC) for residential solar PV expired on December 31, 2025. However, solar is still an excellent investment in Hawaii for several reasons:
Adding a qualifying battery to your system means you can still capture federal tax savings on the battery portion of your investment.
The total timeline from signing a contract to generating solar power is typically 8–16 weeks. Here is a breakdown:
The physical installation is the quickest part. Most of the timeline is permitting and utility approval, which we handle entirely on your behalf.
System size depends on your electricity consumption, roof space, and shading. Most Oahu homes need 8–14 kW (17–30 panels). A good rule of thumb: take your monthly electric bill in kWh and divide by 130 to get an approximate kW system size.
The best way to find out is to use our Solar Calculator, which estimates your ideal system size based on your actual electric bill and energy goals.
Not necessarily, but your roof should be in good condition. Solar panels last 30+ years, so if your roof needs replacement within the next 10 years, it makes sense to re-roof first. During our free site survey, we assess your roof's condition and let you know if any repairs are needed.
If you do need roofing work, Alternate Energy Hawaii also offers roofing services, so we can bundle both projects together for a seamless experience.
With battery storage (e.g., Tesla Powerwall 3): Your home seamlessly switches to battery power within milliseconds. You likely will not even notice the outage. Your solar panels continue generating and recharging the battery during the day, so you can potentially ride out extended outages.
Without battery storage: Your solar panels automatically shut off for safety reasons. This is an anti-islanding requirement that protects utility workers from live wires. Your home will lose power just like your neighbors.
This is one of the top reasons Hawaii homeowners are adding battery storage to their solar systems.
Yes! Battery retrofits are one of our most popular services. We can add a Tesla Powerwall 3 to most existing solar systems, regardless of who installed the original panels. The Powerwall 3 has a built-in inverter, which simplifies the retrofit process.
Adding a battery also opens the door to HECO's BYOD Plus program, which pays you for allowing HECO to dispatch your battery during peak demand—potentially earning you $400/kW upfront.
We are selective about the equipment we install, choosing only brands with proven performance in Hawaii's climate:
All equipment is backed by manufacturer warranties plus our own installation warranty.
Yes, we offer several financing options to fit different budgets:
Many homeowners find that their monthly loan payment is less than their old electric bill, resulting in immediate savings from day one.
We stand behind every installation with comprehensive warranty coverage:
Learn more on our Warranties page.
Most roofs in Hawaii are suitable for solar. The ideal conditions are:
During our free site assessment, we use satellite imagery and on-site evaluation to determine your roof's solar potential, optimal panel layout, and any shading concerns.
Solar PV (photovoltaic) converts sunlight into electricity that powers your entire home—lights, appliances, AC, and everything else on your electric bill.
Solar hot water (solar thermal) uses the sun's heat to warm your domestic water supply. It only offsets the energy used for water heating, which is typically 30–40% of a home's electricity in Hawaii.
Many homes benefit from having both. Not sure which is right for you? Try our Solar vs Hot Water Advisor tool.
SRE (Smart Renewable Energy) Export is HECO's current program for new solar installations that export excess energy to the grid. It uses time-of-use (TOU) rates, meaning the value of your exported energy varies by time of day:
SRE rates are locked for 7 years from your interconnection date. This is where battery storage becomes powerful—you can store daytime solar energy and export it during the high-value peak window for maximum credit.
Learn more at our HECO Program Navigator.
BYOD Plus (Bring Your Own Device Plus) is HECO's grid services program for battery owners. When you enroll, you allow HECO to dispatch your battery for up to 2 hours per day during peak demand events. In return, you receive:
For a Tesla Powerwall 3 (11.5 kW), that is approximately $4,600 upfront (or $9,200 with the LMI adder). The battery is still available for backup and self-consumption the rest of the time.
Yes! SRE and BYOD+ are complementary programs. SRE governs how your exported solar energy is credited, while BYOD+ compensates you for allowing grid dispatch of your battery. Many of our customers enroll in both to maximize their return on investment.
Use our HECO Program Navigator to see which combination works best for your situation.
Under SRE's time-of-use rates, the peak evening window (5pm–9pm) pays $0.329/kWh on Oahu—nearly 2.5 times the daytime rate. The strategy is simple:
This strategy can increase your annual solar savings by 30–50% compared to exporting all energy during daylight hours. The Tesla Powerwall 3 can be programmed to automate this behavior.
Net Energy Metering (NEM) was Hawaii's original solar program where customers received full retail credit for every kWh exported to the grid. NEM was closed to new applicants in October 2015 due to grid capacity concerns.
It was replaced by a series of successor programs: Customer Grid Supply (CGS), Customer Self-Supply (CSS), and eventually today's Smart Renewable Energy (SRE) Export program. Existing NEM customers are grandfathered into their agreement terms.
Generally, no. If you are on the original NEM program, you receive full retail credit for your exports, which is significantly more valuable than SRE rates. Switching is a one-way decision—you cannot go back to NEM.
However, if you are adding a battery or significantly expanding your system, it may be worth evaluating whether the combination of SRE peak rates plus BYOD+ payments could offset the loss of NEM credits. We can model both scenarios for you during a free consultation.
SRE export rates vary by island and time of day. Here are the current rates:
| Time Period | Oahu | Hawaii Island | Maui |
|---|---|---|---|
| Daytime (9am–5pm) | $0.135/kWh | $0.113/kWh | $0.128/kWh |
| Peak (5pm–9pm) | $0.329/kWh | $0.290/kWh | $0.312/kWh |
| Overnight (9pm–9am) | $0.189/kWh | $0.167/kWh | $0.178/kWh |
Rates are locked for 7 years from your interconnection date. Check our HECO Program Navigator for the latest rates.
Your HECO program is listed on your monthly electric bill under your rate schedule. Look for codes like:
You can also log in to your HECO account online or call HECO directly. If you need help understanding your program, contact us and we can review your bill.
The federal Investment Tax Credit (ITC) allows you to deduct a percentage of your solar investment from your federal income taxes. Important updates for 2026:
For full details, visit our Incentives & Tax Credits page.
Hawaii offers a state Renewable Energy Technologies Income Tax Credit (RETITC):
This credit is applied directly against your Hawaii state income tax liability. If the credit exceeds your tax for the year, the unused portion can be carried forward. This is one of the most generous state solar incentives in the country and remains available even after the federal residential PV credit expiration.
The payback period is the time it takes for your cumulative energy savings to equal your net system cost (after incentives). We calculate it by:
Most Hawaii solar systems pay for themselves in 5–8 years, with 25+ years of additional savings after that. Use our Solar Calculator to estimate your specific payback period.
Our 25-year projections assume a 3% annual utility rate increase, which is conservative based on HECO's historical rate trends. Here is why those numbers get large:
Solar locks in your energy cost at installation. The longer you own your system, the greater the gap between what you would have paid HECO and what you actually pay.
We work with several lenders to give you flexible payment options:
Many customers choose cash or the 0% credit union option for the best long-term value. We can discuss all options during your free consultation.
Yes. In Honolulu County, solar energy systems are exempt from property tax increases for 25 years. This means that even though solar adds value to your home, your property taxes will not increase because of the system. Other Hawaii counties have similar exemptions.
This is an often-overlooked benefit—you get the property value increase (studies show solar adds 3–4% to home value) without the tax increase.
Yes, solar hot water systems qualify for excellent incentives:
Combined, these incentives can reduce the net cost of a solar hot water system significantly. Visit our Incentives page for current amounts.
Under SRE, your HECO bill shows separate line items for energy imported from the grid and credits for energy exported. The credits are calculated at time-of-use rates based on when the energy was exported (daytime, peak, or overnight). Export credits offset your import charges on the same bill.
If your credits exceed your usage in a billing cycle, the excess carries forward as a credit to the next month. You will still pay HECO's minimum monthly customer charge (approximately $25/month on Oahu) regardless of your credit balance.
The Tesla Powerwall 3 is a home battery system with these key specifications:
As a Tesla Certified Premier Installer, Alternate Energy Hawaii is authorized to install and service Powerwall systems throughout Hawaii.
Most Hawaii homes do well with a single Powerwall 3 (13.5 kWh). You may want to consider two Powerwalls if:
During system design, we analyze your usage patterns and recommend the optimal number of batteries for your goals.
Modern solar panels are built to last. Here is what to expect:
Solar panels have no moving parts, which means very little can go wrong. They continue producing power well beyond their warranty period, making them one of the most durable home investments you can make.
REC 460W panels use heterojunction technology (HJT), which combines two types of silicon to achieve higher efficiency and better performance in hot climates like Hawaii. Key advantages:
REC is a Tier 1 European manufacturer with an excellent track record. We also install Hyundai TOPCon panels as an alternative option.
Microinverters (Enphase IQ8): Each panel gets its own small inverter. This means each panel operates independently—if one panel is shaded or has an issue, it does not affect the others. Microinverters also enable panel-level monitoring so you can see exactly how each panel performs.
String inverters: All panels connect in series to a single central inverter. They cost slightly less but if one panel underperforms (due to shade or debris), it can reduce the output of the entire string.
We primarily install Enphase microinverters because they offer better performance, individual panel monitoring, and superior reliability for Hawaii's varied rooflines and partial-shading conditions.
Every system we install comes with monitoring so you can track your energy production in real time:
Monitoring helps you verify your system is performing as expected and alerts you to any issues. Our service team also monitors systems proactively and can reach out if we detect a problem.
All solar panels gradually lose a small amount of output over time. This is normal and factored into our savings projections. With the REC 460W HJT panels we install:
Premium panels like REC degrade more slowly than budget panels, which is one reason we choose them—more energy over the life of the system means a better return on your investment.
Yes. Solar panels installed in Hawaii are engineered for our specific conditions:
We have been installing solar in Hawaii since 1993. Our mounting systems and equipment choices are specifically selected for the islands' unique climate challenges.
Here is the typical timeline for a residential solar + battery installation:
We keep you updated at every stage and handle all paperwork, permits, and coordination with HECO.
You do not need to be home for the entire installation. However, we ask that you or an authorized adult be available at the start and end of each installation day so our crew can review the plan, access the electrical panel, and walk you through the completed work.
Installation typically takes 1–3 days. Our crew works during normal business hours (approximately 7:30am–4:00pm).
Possibly. Whether your electrical panel needs modification depends on its age, capacity, and available breaker spaces. Common scenarios include:
We assess your electrical panel during the site survey and include any necessary upgrades in your proposal. As a licensed electrical contractor, we handle all panel work in-house.
HECO interconnection is the process of getting your solar system approved to connect to the utility grid. Here is how it works:
We handle the entire interconnection process for you. The PTO step is typically the longest wait (2–6 weeks), but we track it closely and push things along.
After installation, your system must pass the following inspections:
We schedule all inspections on your behalf. Our installations are designed to pass on the first inspection—we have a 98%+ first-pass rate because we build to code every time.
Yes, 100%. We manage the entire paperwork process from start to finish:
Going solar should not mean drowning in paperwork. Our team handles everything so you can focus on enjoying your new system.
You can schedule a service call through any of these methods:
Our service team is available Monday through Friday, 7:30am to 4:00pm. We typically respond within 1 business day and schedule service visits within 1–2 weeks.
Our standard service call rate is $250 plus tax. This covers a technician visit, system diagnosis, and minor adjustments. If parts or additional labor are needed, we provide a separate quote before proceeding.
Warranty-covered issues are handled at no cost to you. If the service call reveals a manufacturer defect or installation issue covered by your warranty, the service fee may be waived.
If another company or unlicensed individual has modified, repaired, or altered your solar system, it may void our workmanship warranty. This includes:
If you need service, always contact us first. Manufacturer warranties (REC, Enphase, Tesla) are handled separately through their own terms and are generally not affected by third-party work.
Replacement part timelines vary by component:
We maintain local inventory of the most common parts to minimize wait times. For warranty claims, we work directly with manufacturers to expedite replacements.
Solar PV systems require very little maintenance. Panels have no moving parts and are cleaned naturally by rain in most locations. That said, we recommend a professional system check every 3–5 years to:
Contact our support team to schedule a system health check.
All systems we install include free monitoring through the equipment manufacturer's platform:
We also monitor our customers' systems on the back end and may proactively reach out if we detect underperformance or an equipment alert.
We install the full line of Mitsubishi Electric ductless and ducted systems:
Mitsubishi mini-splits are ideal for Hawaii homes because they are highly efficient, whisper-quiet, and do not require ductwork. Learn more on our Air Conditioning page.
Mini-split systems offer several advantages over traditional central AC, especially in Hawaii:
Central AC can still make sense for new construction with existing ductwork. We can help you evaluate both options.
Absolutely. Air conditioning can account for 30–50% of a Hawaii home's electricity usage. By pairing solar with AC, you can:
Many customers add solar and AC together as a bundled project. Use our Solar Calculator and include your AC usage for an accurate estimate.
We specialize in Mitsubishi Electric systems, but our licensed HVAC technicians can service and repair most major AC brands. For new installations, we exclusively recommend Mitsubishi due to their superior efficiency, reliability, and warranty support in Hawaii's climate.
If you have an existing non-Mitsubishi system that needs service, contact us and we will let you know if we can help.
This depends on your specific situation. Solar hot water can be more cost-effective per BTU for water heating, but PV panels offer more flexibility since they generate electricity for any purpose. Factors to consider:
Try our Solar vs Hot Water Advisor tool for a personalized recommendation.
Solar hot water systems require periodic maintenance every 3–5 years, which typically includes:
Regular maintenance extends system life and keeps efficiency high. We offer solar hot water maintenance services—contact our service team to schedule.
Solar hot water systems qualify for several valuable incentives:
These incentives combined can significantly reduce the upfront cost. Visit our Incentives page for a complete breakdown of available credits and rebates.
With proper maintenance, a solar hot water system typically lasts:
Regular maintenance every 3–5 years (fluid replacement, anode rod checks) is key to maximizing system life. Many of our solar hot water installations from the early 2000s are still operating well today.
Our team has been helping Hawaii homeowners go solar since 1993. Get a free, no-pressure consultation.