Independent education, real-world experience, and no-pressure planning tools.

Home energy made understandable

Make smarter energy decisions for your home.

Straightforward calculators and plain-English guides for electricity costs, solar, batteries, EV charging, heat pump heating and cooling, and heat pump water heating.

Explore the calculators Estimate solar savings

Your 60-second energy snapshot

Enter your bill and what you're thinking about. See where you're headed, then jump to the right tools with your numbers filled in.

$
I'm thinking about
Electricity use
Monthly bill
Solar + battery could save

Your next steps

    Free planning tools. Put your own numbers to work.

    Each tool answers one practical home-energy question and shows the assumptions behind the estimate, so you know exactly where the numbers come from.

    Best place to start

    Future Electricity Cost

    See how your current bill, an EV, heat pumps and rising PG&E rates could affect your costs over 25 years, and how much solar and a battery could save.

    Open calculator

    EV Charging Cost

    Compare home charging with gas for your actual car, and see how much solar would cover it.

    Open calculator

    Solar & Battery Savings

    An honest savings estimate under PG&E's current solar rules, with and without a battery.

    Open calculator

    Battery Backup Planner

    Estimate how long Tesla, FranklinWH or Enphase batteries could keep your essentials running.

    Open planner

    Heat Pump HVAC

    Compare heating and cooling costs with your current system, plus the solar to cover it.

    Open calculator

    Heat Pump Water Heater

    Compare gas, propane and electric water heating with a heat pump water heater.

    Open calculator

    Home Heating Warm-Up

    How long a gas furnace and a heat pump take to warm your home, and what each costs.

    Open calculator

    SEER2 & HSPF2 Savings

    Turn efficiency ratings into dollars: 15 years of savings from a more efficient heat pump.

    Open calculator

    Panel Readiness Check

    See if your electrical panel can handle a heat pump, EV charger, or solar and battery.

    Open check

    New Home Energy Planner

    Building new? Compare mixed-fuel and all-electric designs and size solar before construction.

    Open planner

    Start broad, then explore the details.

    Not sure which tool to use? Most homeowners get the most out of them in this order.

    Step 1

    See the big picture

    Start with your future electricity costs: what your home uses today plus what you're thinking of adding.

    Future Electricity Cost

    Step 2

    Check each decision

    Use the focused EV, heat pump, water heater and battery tools when you want a more detailed answer on one upgrade.

    Browse the focused tools

    Step 3

    Confirm it fits your home

    Check whether your electrical panel can take it, then bring your results to your next conversation with a pro.

    Panel Readiness Check

    Learn before you buy.

    Short, plain-English guides to how the pieces fit together, with the questions to ask before you sign anything.

    Robert Kelly on a mountain bike ride above Marin

    Robert Kelly

    Founder, NRG Geek

    27years in Marin
    26+years building and improving homes
    16+years in solar and energy

    Hi, I'm Robert Kelly.

    Marin has been my home for 27 years. I'm a homeowner, husband, father, neighbor, and avid mountain biker.

    For more than 26 years, I've helped people plan, build, and improve their homes and businesses. For over 16 of those years, I've specialized in helping homeowners and businesses make informed decisions about solar, battery storage, electrification, and energy costs.

    I created NRG Geek because good energy decisions start with understanding your own numbers. These tools show the math clearly, so you can evaluate your options and walk into any conversation with a contractor knowing the right questions to ask.

    NRG Geek is my personal educational platform. I'm also Director of Partnerships and an employee-owner at SolarCraft.

    Ask Robert.

    Have a question the calculators didn't answer? Send it over. No pressure, just a straight answer.

    • Include your calculator results if you have them.
    • Mention your county and PG&E rate plan if you know it.
    • Photos of your electrical panel help with upgrade questions.

    Prefer email? Write to rkelly@nrggeek.com.

    By sending, you agree Robert may contact you by email, or by phone if you include a number, about your question. NRG Geek does not sell personal information. See the Privacy Policy.