Creator & Energy Systems Engineer

Marcus Delacroix

JouleIO is built and maintained by Marcus Delacroix, a power systems and residential electrification engineer focused on replacing aggressive solar sales pitches with transparent kWh math grounded in EIA utility tariffs and NREL irradiance data.

Marcus Delacroix

Founder & Lead Power Systems Engineer

Focus: EIA State Tariffs, Solar PV Derating & Home Loads

Most online solar and home energy calculators exist for one reason: to capture your home address and phone number so five local installers can call you before dinner. Worse, many of those calculators assume unrealistic 100% DC-to-AC solar efficiency, ignore inverter clipping and panel degradation, or apply flat national electricity rates in states where tiered or time-of-use (TOU) tariffs dominate.

I created JouleIO so homeowners, renters, and DIY electrifiers can run honest engineering numbers on appliance phantom loads, Level 2 EV charger circuit sizing, battery backup runtime (accounting for inverter tare loss and depth of discharge), and solar payback periods using state-level U.S. Energy Information Administration (EIA) retail electricity rates.

Primary Datasets & StandardsU.S. Energy Information Administration (EIA Electric Power Monthly Table 5.6.A), NREL PVWatts peak sun-hour maps, EPA ENERGY STAR appliance load benchmarks, and NEC continuous-load (125%) rules.

System Loss AccountingSolar and battery calculators explicitly include DC-to-AC derate factors (typically 0.82–0.86), LiFePO4/NMC usable depth-of-discharge limits, and Level 2 EV onboard charger efficiency (~88%–92%).

Our Engineering Principles

1. State-Specific Utility Rate Baselines

Running a dehumidifier or charging an EV in Washington state (~11–12¢/kWh) costs a fraction of what it costs in California or Massachusetts (30¢+/kWh). Our calculators pre-load current EIA state residential averages while letting you override the exact ¢/kWh from your utility bill.

2. Real-World Derating Over Nameplate Hype

A 400W solar panel rarely outputs 400W AC at your breaker panel, and a 10 kWh home battery does not deliver 10 kWh of AC load after inverter conversion losses. Every JouleIO model accounts for real-world conversion efficiency.

3. Zero Installer Lead Capture

JouleIO never asks for your street address, email, or phone number to display solar sizing or electricity cost results.

Have a Tariff Update or Load Question?

If your utility updated its residential baseline tariff or you want to verify an appliance wattage benchmark, reach out directly.

Contact Marcus Read Our Methodology