SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/solar-inv-eff

What default inverter efficiency does NREL's PVWatts use?

96% nominal efficiency.

Start playing free

  1. 70%
  2. 96% ✔
  3. 99.9%

Why: No inverter is perfect. Some energy becomes heat during DC to AC conversion, so PVWatts assumes about 4% is lost.

Huh, didn't know that: The PVWatts V8 tool accepts inverter efficiencies from 90% to 99.5%.

The dad joke
Why did the sun go to school? To get a little brighter!
Like this card?
Play the game

References

Answer: 96%. No inverter is perfect. Some energy becomes heat during DC to AC conversion, so PVWatts assumes about 4% is lost.

  1. NREL Developer Network: PVWatts V8 API developer.nrel.gov/docs/solar/pvwatts/v8
    inv_eff, decimal, default 96, Inverter efficiency at rated power.
    Checked 2026-10-10.
  2. NREL: PVWatts Version 5 Manual www.nrel.gov/docs/fy14osti/62641.pdf
    The default nominal efficiency ηnom is 0.96.
    Checked 2026-10-10.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Home & YardNREL's current PVWatts (Version 8) uses a default DC-to-AC ratio of 1.2. What does that mean?Home & YardWhen a PV array briefly produces more power than the inverter's AC rating, what happens?Home & YardWhat kind of electricity do solar PV cells generate?

That's stuff everyone should know.