Heat your water with Hawaiian sunshine. Solar thermal systems are one of the most cost-effective renewable investments — especially with increased Hawaii Energy rebates and the 35% state tax credit.
Solar collectors on your roof absorb heat from sunlight and transfer it to a storage tank. A pump circulates fluid between collectors and tank. Your conventional water heater serves as backup for cloudy days. In Hawaii’s climate, solar can provide 80–90% of your hot water needs year-round.
AEI installs SunEarth solar hot water systems — American-engineered, built for Hawaii conditions. Three product lines to match your household.
This is one of the most common questions we get. Here’s how the two technologies compare.
| Factor | Solar Hot Water | Solar PV |
|---|---|---|
| Purpose | Heats water only | Powers everything (including water heater) |
| Upfront Cost | $4,000–$7,000 | $15,000–$45,000 |
| State Tax Credit | 35% up to $2,250 | 35% up to $5,000 |
| Hawaii Energy Rebate | ✓ Yes (increased through June 2026) | No |
| Payback Period | ✓ 3–5 years | 6–9 years |
| Maintenance | Every 3–5 years | Minimal |
| Best When | Electric water heater, 3+ people, no PV yet | Want to offset all electricity |
| Can Combine | ✓ Yes — reduce load so PV can be smaller | ✓ Yes — PV handles remaining load |
See your numbers: Calculate your solar hot water savings
Solar hot water qualifies for some of the best incentives in Hawaii — and rebates have been increased through June 2026.
Apply on your Hawaii state tax return.
Rebate amount varies by system type. Contact us for current amounts.
Solar hot water system value excluded from property tax assessment.
Before incentives. With the 35% state credit and Hawaii Energy rebate, net cost can be as low as $1,500–$3,500. One of the fastest-payback renewable investments in Hawaii.
Get Free EstimateSolar hot water systems are low-maintenance, but periodic service keeps them running at peak efficiency. Here’s what’s needed every 3–5 years:
Ensure proper fluid levels and condition for efficient heat transfer.
Check for cracks, moisture intrusion, and seal integrity.
Verify circulation pump operation and controller settings.
Inspect sacrificial anode rod in storage tank and flush for mineral buildup.
AEI provides professional maintenance service. Our 10-year warranty covers workmanship. Collector warranties are typically 10 years from manufacturer.
From consultation to activation, here’s what to expect when you go solar hot water with AEI.
We assess your roof orientation and condition, review household size and hot water usage, and recommend the right system type and tank size for your home.
Our engineer finalizes the system design. We complete and submit your Hawaii Energy rebate application and provide guidance on the 35% state tax credit.
Our crew mounts collectors on your roof, connects plumbing, installs the storage tank, and tests the complete system for proper operation.
We schedule the city inspection, commission your system, and walk you through operation and maintenance. You start saving from day one.
It depends on your household size, current water heater type, and whether you already have PV. For households of 3+ with an electric water heater and no PV, solar hot water often has the fastest payback. Try our advisor tool for a personalized recommendation.
In Hawaii, typically 80–90% year-round. Your electric backup element handles the rest on cloudy days or during periods of heavy hot water use.
Reduced output but still produces heat. Your electric backup element activates automatically when needed, so you always have hot water.
Based on household size: 2 people = 60–80 gallon tank, 3–4 people = 80–120 gallon tank, 5+ people = 120+ gallon tank. We’ll recommend the right size during your free consultation.
Typically 1–2 days for residential systems. We handle permitting and inspections as well.
“We got our solar hot water system installed and the payback was under 3 years with the rebate and tax credit. Now we’re adding solar panels too — AEI made the whole process easy.”
“We did solar hot water first, then added PV panels a year later. Because the SWH handles our water heating, we needed a smaller PV system — saved us thousands on the solar install.”
“Our electric water heater was costing us over $100 a month. After going solar hot water, that dropped to almost nothing. Wish we’d done it years ago.”
Get a free estimate and find out how much you can save with solar hot water. Increased rebates available through June 2026.