How Many kWp Do You Need for Your Home?

"How many kWp does my home need?" The question we hear most often on WhatsApp from Indonesian residential homeowners. Before crunching numbers, decide first how independent you want to get from PLN (Indonesia's state utility). Are you covering 50% of your usage so the bill drops in half? 70% so your home stays comfortably independent when the next tariff hike lands? Full hybrid with battery so you can ride out a 24-hour blackout? The kWp size flows directly from that choice, plus three technical variables: your PLN connection rating, your average bill, and your city (which affects panel output).

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TL;DR

• Simple formula: kWp = monthly bill / (offset target x PLN tariff x output per kWp per month)
• Defaults: 60% offset, Rp 1,444 per kWh (R-1 small), Rp 1,699 (R-1 large), 110 kWh per kWp per month
• Tables below: recommended kWp per VA tier and bill range
• Don't oversize: target 60 to 75% self-consumption, not 100% production. After Permen ESDM 2/2024, surplus exports to PLN earn zero credit (the residential zero-export policy), so any extra production you don't use yourself becomes wasted investment. Independence is gradual, not all-or-nothing.

kWp recommendation tables per VA tier

1300 VA (PLN R-1 small subsidy)

Monthly bill	Recommended kWp	Monthly output
Rp 300,000 to 500,000	1 kWp	~110 kWh
Rp 500,000 to 800,000	1.5 kWp	~165 kWh
Rp 800,000 to 1.2 million	2 kWp	~220 kWh

2200 VA (PLN R-1 subsidy)

Monthly bill	Recommended kWp	Monthly output
Rp 600,000 to 1 million	2 kWp	~220 kWh
Rp 1 to 1.5 million	2.5 kWp	~275 kWh
Rp 1.5 to 2 million	3 kWp	~330 kWh
Rp 2 million+	3.5 kWp+	~385 kWh+

3500 VA (PLN R-1 non-subsidy)

Monthly bill	Recommended kWp	Monthly output
Rp 1 to 1.5 million	2.5 kWp	~275 kWh
Rp 1.5 to 2 million	3 kWp	~330 kWh
Rp 2 to 3 million	4 kWp	~440 kWh
Rp 3 million+	5 kWp+	~550 kWh+

5500 VA (PLN R-1 non-subsidy / premium)

Monthly bill	Recommended kWp	Monthly output
Rp 1.5 to 2 million	3 kWp	~330 kWh
Rp 2 to 3 million	4.5 kWp	~495 kWh
Rp 3 to 4 million	5.5 kWp	~605 kWh
Rp 4 million+	6.5 kWp+	~715 kWh+

7700 VA+ (premium / EV households)

Monthly bill	Recommended kWp	Monthly output
Rp 3 to 5 million	6 kWp	~660 kWh
Rp 5 to 8 million	8 kWp	~880 kWh
Rp 8 million+	10 kWp+	~1,100 kWh+

The full formula (if you want to do it yourself)

kWh_target_per_month = monthly_bill / PLN_tariff_per_kWh
kWp = ceil(kWh_target x offset_target / output_per_kWp_per_month)

• Offset target: 60% by default (conservative). Drop to 50% if budget is tight, or push to 75% if you use most of your power during the day.
• PLN tariff per kWh: Rp 1,444 (R-1, 1300 to 2200 VA), Rp 1,699.53 (R-1, 3500 VA and up).
• Output per kWp per month: 110 kWh as the Indonesia average. Bump to 120 to 130 kWh if you're in Surabaya, Bali, or Kupang (high irradiance). Drop to 90 to 100 kWh in Bandung or Yogyakarta.

Worked example

Surabaya home, 2200 VA, Rp 1.5 million per month

• Monthly usage: 1,500,000 / 1,444 = ~1,039 kWh
• Offset 60%: solar covers 624 kWh
• Surabaya output: 120 kWh per kWp per month
• kWp = 624 / 120 = 5.2 kWp

That looks high for 2200 VA. The clue: 1,039 kWh is heavy usage for that connection. The case is probably R-1 3500 VA in practice. For a typical 2200 VA home at Rp 1.5 million, the recommendation lands at 3 kWp (matches the table).

The lesson: use the calculator. The table is a starting point; the calculator handles real-world variables.

Solar calculator for your home

Why 60% offset is the default, not 100%

Net metering rate was already below the retail tariff. Under Permen 26/2021, exported surplus was credited at 65% of the regular tariff, not parity.

After Permen ESDM 2/2024, residential rooftop solar PV is zero-export. Even the 65% credit is gone. Surplus flowing to the grid earns nothing. Every kWh of production not consumed at home is wasted investment.

Self-consumption ceiling. A typical home self-consumes 60 to 75% of panel output, depending on daytime usage. The rest would have flowed to the grid (now earns zero). Sweet-spot sizing matches your self-consumption ceiling.

Diminishing returns. Going from 3 kWp to 5 kWp adds Rp 25 to 30 million but only Rp 200,000 to 300,000 per month in extra savings (the surplus you can't self-consume earns zero). Payback on the extra panels stretches to 10 to 12 years, much longer than the base system's 6 to 8.

When oversizing makes sense

• Heavy daytime usage: full-time WFH for two people, home office, AC running 8 to 12 hours a day. Self-consumption can hit 80%+.
• Daytime EV charging: a car charged during work hours (the partner's car at home), adding 5 to 10 kWh of daytime load.
• Future expansion in 1 to 2 years: planning to add bedroom AC, a pool pump, or other big loads. Sizing up upfront saves a return-trip install fee.

When undersizing is fine

• Nighttime-dominant usage: 9-to-5 office workers, empty house during the day, most consumption at night. Lower self-consumption, so a bigger system isn't optimal.
• Tight budget: start small (1 to 2 kWp) and expand later. Caveat: expansion needs another technician visit plus modification work, so it's better to commit once if you can afford it.

What the table can't capture

• Roof orientation (north-facing is ideal in Indonesia; east or west drops 10 to 15%; south drops 20%+).
• Shading from trees, neighboring buildings, water tanks.
• Available roof area (a small roof can cap your maximum kWp).

All of these get pinned down during the installer's site survey. The table and calculator give you a starting point; the survey confirms the final number.

Next step

Got a rough kWp number from the table? Use the calculator for a payback estimate.

Or chat with us if your case is unusual (home business, villa, boarding house, or a tropical home that doesn't fit the standard tables).