Slightly, yes. To put the same energy into the battery, Level 1 charging usually draws a bit more electricity from the wall than Level 2. ENERGY STAR says Level 2 chargers are on average about 10% more efficient than Level 1. The main reason is time: during a long Level 1 session, the car’s computers, pumps and battery management stay awake for many more hours, and in cold weather battery heating takes a larger share of the low power.
Where the Losses Come From
- Fixed overhead: the car uses a roughly constant amount of power just to stay awake while charging. Spread over 30 hours instead of 6, it adds up.
- Battery conditioning: in cold weather, heating the battery can use a big part of a 1.4 kW supply.
- On-board charger efficiency: most on-board chargers are more efficient near their rated power than at very low power.
What It Costs You
Suppose you add 300 kWh to the battery per month. At the July 2026 US average residential price of 18.31 cents per kWh reported by the EIA, a 10% efficiency difference is about 30 kWh, or roughly $5–6 per month. In cold climates the gap can be larger; in mild weather smaller. Use our home charging cost guide to work out your own numbers.
Other Reasons to Choose Level 2
- Fits charging into short off-peak windows on time-of-use rates.
- Adds range four or more times faster.
- Keeps up in winter when Level 1 may barely cover battery heating.
Choosing an ENERGY STAR certified charger also reduces standby use; ENERGY STAR says certified chargers use 40% less energy in standby mode. Options include plug-in portable units like the EVDANCE EV-ACS3210T 32A NACS portable charger and hard-wired units like the EVDANCE EV-ACT5006T 48A Level 2 wall charger.
Frequently Asked Questions
Is Level 1 charging more expensive?
Slightly, because of lower efficiency, typically a few dollars a month for an average driver.
Does a charger use power when not charging?
Yes, a small standby load. ENERGY STAR certified chargers use less.
Is DC fast charging more efficient?
Efficiency varies, but public DC fast charging usually costs more per kWh.
Related Reading
- Is Level 1 Charging Bad for Your Battery?
- Is a Level 2 Charger Worth It?
- Smart Charging and Time-of-Use Tariffs
Key Takeaways
- Level 2 is on average about 10% more efficient than Level 1 (ENERGY STAR).
- Longer Level 1 sessions keep car systems running longer.
- For a typical driver the difference is a few dollars a month.