FULL CALCULATOR

Solar calculator: size a system for your home.

Tell us your home situation: city, PLN connection, monthly bill. We'll show you how much of your home can leave PLN behind, the system size required, and a 25-year cost trajectory. Every assumption is visible. The real numbers come later, on WhatsApp.

What this calculator computes

This residential solar calculator returns four numbers at once: the panel size you need (kWp), the inverter capacity to install (kW), the battery capacity to cover nighttime use plus cloudy-day buffer (kWh), and the equipment investment estimate in Rupiah. It also charts a 25-year projection of your bill with and without solar. The point is to give you a sensible sizing number before you talk to any installer.

How it works under the hood: the engine pulls peak sun hours (PSH) per city from Global Solar Atlas, multiplies by the panel area required to cover a chosen percentage of your daily home usage, then matches the inverter to your installed PLN rating (PLN VA plus a 15% buffer), and sizes the battery from your daytime-vs-nighttime usage pattern plus the number of cloudy days you want covered. Equipment pricing is calibrated against real field-quote data from our partner installer network (around 100 residential quotes, Java and Bali, Q2 2026), not retail-website guesses.

The inputs that move the result the most: city location (PSH ranges 4.2 to 5.8 across Indonesia, which directly drives panel count), PLN VA rating (sets the inverter), monthly bill (proxy for daily kWh use), coverage % (your independence target from PLN: 50 to 80% is the savings sweet spot, 100% means free of PLN on normal days), and day-vs-night usage pattern (sets battery size). The result is a sizing estimate, not a quote. Real per-home numbers only emerge after a site survey: roof orientation, shading, building structure, and local PLN conditions all shift the final figure by 10 to 15%.

Primary goal

Energy independence first, savings second.

Solar's primary win isn't lower bills, it's freeing your home from PLN dependency: protected from yearly rate hikes, electricity costs locked for the next 25 years, blackout-safe. Savings come as a side effect once you're independent. Because Indonesia has no net metering, a battery is mandatory in every setup so daytime production isn't wasted and you draw from your own power at night, not PLN.

Your home's baseline

Electricity use

29.4 kWhper day

(~883 kWh per month)

Based on a Rp 1,500,000/month bill at the R-1 3500 sampai 5500 VA tariff (Rp 1,699.53 per kWh, PLN April 2026), your home uses about 29.4 kWh per day. That's the baseline we use for everything else.

Primary goal: energy control

Covers 70% of your usage

70%grid-free

  • Panels cover about 70% of your daytime electricity use
  • Home usage is 50% daytime, 50% nighttime
  • Real savings ~70% of the bill, with the battery capturing daytime surplus so nothing is wasted
  • "Save while staying semi-independent" mode: PLN rate hikes only affect your remaining usage, not the total
  • Good fit if your priority is lowering the bill while staying covered during blackouts via battery

System configuration

What you'll install on your roof

Panel production

20.7 kWhper day

(~621 kWh per month, assuming 4.5 peak sun hours)

  • Solar panels

    4.6 kWp

    ~8 modules at 580 Wp

  • Inverter

    3.6 kW

    Hybrid-ready

  • Battery

    10.2 kWh

    2 LiFePO4 modules

  • Panels: Jinko Tiger Neo 580W N-type, 8 modules x 580 Wp = 4.6 kWp datasheet rating (~25 m² of roof area)
  • Estimate uses datasheet rating; real-world output varies with temperature, soiling, and installation quality
  • Inverter: Deye Deye 3,6kW 5kW Hybrid | 3600W , 5000W | Low Voltage Battery 3.6 kW Hybrid-ready, sized to MAX of (PLN rating 3500 VA) or (panel 4.6 kWp divided by max DC:AC ratio 1.3)
  • Actual DC:AC ratio = 1.3 (healthy range 1.1 to 1.5)
  • Battery: HinaESS Hi-5 (2 modules x 5.1 kWh = 10.2 kWh nominal LiFePO4)
  • Sized for 50% nighttime usage (100% coverage assumes clear weather with 4.5 peak sun hours, no oversizing)
  • The more nighttime-dominant your use, the bigger the battery (panels only produce by day; at night you time-shift from the battery)

Equipment cost (excludes VAT and labor)

Estimated equipment cost

Rp 67,950,000

Excludes 11% VAT (Rp 7,474,500). Excludes balance of system (mounting, cabling, protection), installation labor, and commissioning.

Payback: about 6 years at your current bill

The number above is for the main equipment only (panels + inverter + battery). Balance of system, installation labor, and transport vary by location (roof condition, panel-to-meter distance, remote-site access), so they're discussed during the site survey. Reach out on WhatsApp below to get a full estimate for your home.

Solar panels
8 modules x 580 Wp = 4.6 kWp
Rp 16,100,000
Inverter
Deye 3.6 kW Hybrid
Rp 18,450,000
Battery
2 modules x 5.1 kWh = 10.2 kWh LiFePO4
Rp 33,400,000
Equipment subtotal
Before VAT, balance of system, and installation labor
Rp 67,950,000

Note: balance of system and installation labor depend on roof condition, panel-to-meter distance, site access (Java-Bali / Sumatra / eastern Indonesia), and PLN SLO certification. Typical balance-of-system range: Rp 3 million per kWp plus Rp 10 million fixed for protection. Typical installation labor: Rp 2 million per kWp. The exact number is set during the site survey.

Remaining PLN dependency

Your PLN bill after solar

Before

Rp 1,500,000

100% PLN

After

Rp 450,000

rest from PLN

  • Your PLN bill drops to Rp 450,000 per month
  • Panels cover 70%, the battery captures daytime surplus to use at night
  • When PLN rates rise next year, your bill goes up only on the remaining usage, not the total
  • If full grid independence is the goal, push coverage to 100% (panels just match daily use plus a nighttime battery, no oversizing)

25-year projection

PLN rates rise. Your bill doesn't have to.

This chart shows total cumulative electricity cost over 25 years. Red line: PLN-only, where annual cost compounds and rates climb 5% per year. Amber line: with solar, starting from the equipment investment of Rp 75.4 million in year zero (excluding balance of system and installation labor), then rising slowly from any remaining PLN draw. The crossover point (year 2031) is where the amber line drops below the red. Hover the dots every 2 years for per-year and per-month detail.

Total cumulative without solarTotal cumulative with solar (starts at upfront Rp 75.4 million)

After year 2031 (the payback point), every additional year is net savings vs. the PLN-only path. Total cumulative difference at year 2050: Rp 482.4 million net of the upfront investment.

Assumptions: PLN rates rise 5% compound, panels degrade 0.5% per year. Coverage at or above 100% has a battery sized to absorb degradation, so the residual stays at 0. Below 100%, the residual PLN cost rises gradually with drift. The upfront investment includes 11% VAT.

Fast response. Free. Consultant, not salesperson. If your home isn't a fit, we'll tell you.

Conservative estimate based on Indonesia's average irradiance and PLN tariffs as of April 2026. Real numbers depend on the specific brands picked, roof orientation, shading, and your local PLN conditions. For precise sizing, chat on WhatsApp. Independence is gradual, not all-or-nothing: we'll recommend sizing that fits, not the biggest system.

How we calculate

Engine assumptions plus technical terms. Open any card for details.

PLN tariff rises 5% per year (compound).
Anticipating subsidy reform plus carbon-pricing pressure. The 2020 to 2025 average for the 1300 to 5500 VA non-subsidized tier was 3.5 to 4% per year; 5% is a forward-looking conservative for 25-year planning.
Irradiance based on your home's location.
Pick your city under "Home location" for a more accurate per-region calculation. Indonesia is equatorial, so every region is solar-viable; output ranges from Excellent (Sumatra, Kalimantan, West Java) to Outstanding (East Java, Bali, NTT, Sulawesi, NTB). The default with no city picked is the Java baseline. Peak Sun Hours (PSH) = equivalent hours of full radiation per day. The math uses the panel datasheet rating; real-world output varies with temperature, soiling, mounting, and installation quality.
580 Wp tier-1 Grade-A modules (Jinko, Trina, LONGi).
Default panel spec. N-type 144-cell, 25-year warranty. Equivalent brands are fine as long as they are Bloomberg Tier-1 with warranty support in Indonesia. Module count = ceil(panel_kwp x 1000 / 580).
Inverter sized to PLN connection plus 15% buffer.
Not to panel kWp. The inverter has to serve the home's max load (= installed VA), regardless of panel size. The 15% buffer covers transient surges plus headroom for degradation. The DC:AC ratio (panel kWp / inverter kW) can run 1.1 to 1.5; midday clipping is small (under 3% per year).
Panels degrade 0.5% per year.
Tier-1 Bloomberg panels lose ~10 to 12% output over 25 years. Linear approximation. Coverage at or above 100% absorbs the degradation via panel and battery headroom (chart: the with-solar line stays flat). Below 100%, residual PLN cost rises gradually with drift.
The coverage % you pick is your independence target, not a fixed residual.
The engine does not assume a 10% residual. You pick 25/50/75/100/150/200%. At 100% or above you are free of PLN on normal days, with the battery handling cloudy stretches. Below 100%, part of usage still draws from PLN, the rest from solar.
Investment uses Q2 2026 retail plus 11% VAT.
Tier-1 panels Rp 5.5 million/kWp + hybrid inverter Rp 3 million/kW + LFP battery Rp 5 million/kWh + balance of system Rp 1.8 million/kWp + labor Rp 5 million flat + Java/Bali transport Rp 0. Source: market triangulation Q2 2026, refreshed quarterly. The exact number depends on the specific brands picked, mounting, and the actual roof orientation.
kWp (kilowatt-peak)
Maximum panel capacity at standard test conditions. A 2.5 kWp system = 2,500 watts peak output.
Payback period
Years until total savings equal the install capex. After payback, panels produce free electricity for the rest of the system life (~25 years).
Yield (specific yield)
AC kWh produced per kWp of panels per day (after inverter, cabling, and soiling losses). Indonesia averages 3.0 to 3.7 depending on location and roof orientation. The engine uses a Java baseline of 3.1.
Grid-tied vs hybrid
Grid-tied: panels connected to PLN, no nighttime backup, no operation during PLN outages. Hybrid: grid-tied plus battery backup, runs through PLN trips. Juragan Listrik always recommends hybrid (you pick the coverage %); pure grid-tied is not something we sell.

Assumption Glossary term

Frequently asked questions

For something specific to your home, chat on WhatsApp.

How accurate is this calculator?
It's a sizing estimate, not a final quote. The math uses averages: PLN tariff rising 5% per year, peak sun hours (PSH) per city from Global Solar Atlas, equipment retail Q2 2026 plus 11% VAT, and 580 Wp tier-1 panel modules. Yield uses the panel datasheet rating without real-world derating (cell temperature, soiling, mounting quality). The final number from a real installer can vary 10 to 15% depending on the specific panel brand, roof orientation, shading, and field conditions. For a precise number, chat on WhatsApp after a site survey.
What is PSH and why does location matter?
PSH (peak sun hours) is the equivalent number of full-radiation sun hours per day at your home location. Indonesia averages 4.2 to 5.8 PSH. West Java and Sumatra run around 4.5, Bali 4.7, NTT 5.5. The calculator pulls per-city PSH from Global Solar Atlas (Solargis, an open free dataset, looked up per coordinate) instead of using a flat assumption. The higher your location's PSH, the fewer panels you need for the same electricity output. That's why picking your city under 'Home location' makes the result more accurate per region.
How is panel yield calculated?
Monthly yield per kWp = effective PSH x 30 days. Java baseline of 4.5 PSH x 30 = 135 kWh/month per kWp installed. Kupang at 5.8 PSH = 174 kWh/month per kWp. The engine uses panel datasheet ratings directly; real-world output runs lower because of cell temperature, soiling (dust and pollution), and mounting (roof orientation, tilt angle). For conservative planning, build in a 10 to 15% margin, or pick a coverage % slightly above your independence target.
How is equipment cost calculated?
The engine reads retail prices per component, calibrated against real field-quote data from our partner installer network: tier-1 panels Rp 5.5 million per kWp, hybrid inverter Rp 3 million per kW (Growatt under 3 kW, Luxpower 3 to 5 kW, Deye at 5 kW or above), LiFePO4 battery Rp 5 million per kWh. The subtotal you see is equipment only and does NOT include 11% VAT, balance of system (mounting, cabling, protection, around Rp 3 million per kWp), installation labor (around Rp 2 million per kWp), or commissioning. The full all-in number in the field typically runs 25 to 35% above the equipment subtotal.
When does the calculator recommend hybrid vs grid-tied vs off-grid?
Pure grid-tied (panels only, no battery) means lights are off at night and during PLN outages. We don't sell that setup. Hybrid means grid-tied plus battery backup, still connected to PLN, running through PLN trips, with you picking the coverage % from solar (default 70%). Off-grid means no PLN connection at all, with the battery covering the full night. Off-grid is for locations PLN doesn't reach or for homeowners targeting full independence. Our default recommendation is hybrid; off-grid is the fit when there's no PLN at the address or full independence is the explicit goal.
Why is battery sized differently per usage pattern?
The 'When is your electricity use heaviest?' slider (daytime / balanced / nighttime) directly drives battery size. Nighttime-dominant use means a heavy load at night, which means the battery has to store unused panel output from the day to power the home overnight. That requires a bigger battery. Daytime-dominant use (home active during work hours, AC plus WFH plus appliances during the day) means the load draws straight from the panels, so the battery just buffers cloudy stretches and can stay smaller. The engine sizes battery capacity from night-usage fraction x cloudy-day buffer x daily kWh.
What's NOT included in this estimate?
The equipment subtotal covers panels, inverter, and battery only. It does NOT include 11% VAT, balance of system (mounting brackets, DC and AC cabling, breaker protection, surge protection, grounding, monitoring), installation labor (the partner installer crew on site, mounting panels, wiring, commissioning), shipping equipment and crew to the site (Java and Bali typically Rp 0, Sumatra and eastern Indonesia adjusted by distance), or PLN documentation (SLO certification for grid-tied hybrid systems). The full all-in cost typically runs Rp 15 to 18 million per kWp for hybrid systems on Java and Bali. The exact number is set during the site survey.

Methodology and data sources

Irradiance source (PSH per city). The engine reads peak sun hours per city from Global Solar Atlas (Solargis, an open free dataset, looked up per coordinate). Every city in the input list has a specific PSH value, not a flat assumption. Indonesia averages 4.2 to 5.8 PSH; the Java baseline of 4.5 PSH is the default when you don't pick a city.

Equipment pricing calibration. Retail prices per component (panel, inverter, battery, balance of system, installation labor) are calibrated against real field-quote data from our partner installer network on Java and Bali, Q2 2026. Not scraped retail prices and not global benchmark guesses. Refreshed each quarter when the partner updates their pricing sheet.

Engine math. The calculation uses: monthly yield = PSH x 30 days x panel kWp (datasheet rating, no real-world derate); panel kWp = (daily kWh x coverage %) / yield per kWp; inverter kW = PLN VA / 1000 x 1.15 buffer; battery kWh = night-usage fraction x cloudy days x daily kWh / depth-of-discharge 0.8. The default panel module is 580 Wp tier-1 (Jinko, Trina, LONGi, or a Bloomberg Tier-1 equivalent).

Update cadence. Equipment pricing refreshes each quarter as the partner installer updates field-quote rates. PLN tariffs assume a 5% annual compound rise (forward-looking conservative; the historical 2020 to 2025 average for the 1300 to 5500 VA non-subsidized tier was 3.5 to 4% per year). Engine logic and technical assumptions are reviewed quarterly.

Privacy: the math runs in your browser.

We don't store your calculator inputs on our servers. Everything computes client-side. Continue on WhatsApp and we'll send a real per-home quote within 24 to 48 hours, free, with no obligation to proceed.

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