What Size Solar System Do I Need for 2,000 kWh per Month?
Two thousand kilowatt-hours a month is a large residential bill. Confirm the meter before you scale an array to it.
Full breakdown: what size solar system.
Panel-count context for a whole house: how many solar panels.
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Kilowatts, two ways
| Method | Array | 400 W panels, rounded up | Source |
|---|---|---|---|
| Phoenix year: annual kWh ÷ 1,755 | 13.68 kW | 35 | PVWatts v8 |
| 4 peak sun hours, then ÷ (1 − 0.14) | 19.38 kW | 49 | Battle Born hours; PVWatts v5 losses |
| 5 peak sun hours, then ÷ (1 − 0.14) | 15.50 kW | 39 | Battle Born hours; PVWatts v5 losses |
A 2,000 kWh month makes the panel column large, so the 400 W divisor is called out as illustrative only. Phoenix kilowatts use 1,755 from lat 33.45, lon −112.07, tilt 20°, azimuth 180°, 14% losses.
How to size it
Treat a 2,000 kWh month as a claim to verify, then as a division. The year is twelve times the month only if every month really looks like this one.
- Annual energy: 2,000 × 12 = 24,000 kWh.
- Phoenix array: 24,000 ÷ 1,755 = 13.68 kW. That 1,755 is AC kilowatt-hours per kilowatt of DC for the Phoenix inputs in the PVWatts v8 run. Unrounded, an illustrative 400 W panel count rounds up to 35.
- Daily energy: 2,000 ÷ 30 = 66.67 kWh. The 30-day step compares the bill with a monthly average; EIA does not print the number 30.
- 4 peak sun hours: (66.67 ÷ 4) ÷ (1 − 0.14) = 19.38 kW, which rounds up to 49 illustrative 400 W panels.
- 5 peak sun hours: (66.67 ÷ 5) ÷ (1 − 0.14) = 15.50 kW, which rounds up to 39 panels.
Using Louisiana's 14,774 kWh/year again: 14,774 ÷ 12 = 1,231 kWh per month, and 2,000 ÷ 1,231 = 1.62. This page's bill is about 1.62 times the highest state average month in that FAQ, and 2,000 ÷ 899 = 2.22 times the U.S. monthly average. Read the utility's own annual kWh before locking an array to a single high month — the Phoenix math below assumes every month looks like this one, because 2,000 × 12 = 24,000 kWh.
At this size, using the wrong column is a lot of array. 13.68 kW trusts Phoenix's 1,755 kWh per kW, December included at 4.75 (annual plane-of-array 6.54). 19.38 kW trusts 4 peak sun hours and then divides by (1 − 0.14). Neither is a substitute for PVWatts at the address or the solar size calculator with the real loads.
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FAQ
How many kilowatts offset 2,000 kWh a month in Phoenix?
24,000 kWh a year ÷ 1,755 kWh per kW = 13.68 kW. On an illustrative 400 W panel that rounds up to 35.
What do 4 and 5 peak sun hours give?
2,000 ÷ 30 = 66.67 kWh/day. (66.67 ÷ 4) ÷ (1 − 0.14) = 19.38 kW. At 5 peak sun hours the same steps give 15.50 kW.
How many illustrative panels is the generic high end?
The unrounded 4-hour result rounds up to 49 panels of 400 W. The 5-hour result rounds up to 39. The 400 W figure only turns watts into a whole-module count.
Does this replace a PVWatts run at my house?
No. Neither 13.68 kW nor 19.38 kW knows the roof. The Phoenix inputs are lat 33.45 and lon −112.07. Enter the address before sizing a 24,000 kWh year.
Related questions
- What size solar system for 1,500 kWh per month
- What size solar system for 1,000 kWh per month
- What size solar system for 30 kWh per day
All of these questions are listed on the topic map.
Sources
- NREL/NLR PVWatts Version 8 API documentation — accessed Oct 2, 2026.
- PVWatts calculator — accessed Oct 2, 2026.
- NREL PVWatts Version 5 Manual, A. Dobos, September 4, 2014 — accessed Oct 2, 2026.
- Battle Born Batteries, How to Size Solar Panels for a Deep Cycle Battery System — accessed Oct 2, 2026.
- U.S. Energy Information Administration, How much electricity does an American home use? — accessed Oct 2, 2026.