[{"data":1,"prerenderedAt":226},["ShallowReactive",2],{"page-\u002Fblog\u002Fthe-question-calculators-forget":3,"author-mike":189},{"id":4,"title":5,"author":6,"bare":7,"body":8,"dateModified":168,"datePublished":168,"description":169,"extension":170,"howToSteps":171,"kits":171,"layout":172,"meta":173,"navigation":174,"path":175,"schemaType":176,"seo":177,"sources":178,"stem":182,"targetKeywords":183,"titleTag":187,"translationOf":171,"__hash__":188},"content\u002Fblog\u002Fthe-question-calculators-forget.md","The one question every solar calculator forgets to ask","mike",false,{"type":9,"value":10},"minimark",[11,18,23,26,89,92,95,99,102,109,112,116,119,125,131,137,148,152,159,162,165],[12,13,14],"answer-box",{},[15,16,17],"p",{},"Is anyone home during the day? That single question moves the savings from a plug-in solar system by up to 40 percent — more than the choice of kit, more than a battery, more than anything except which way the panel faces. Almost no solar calculator asks it, because the industry grew up in an era when exported power was paid at the retail rate and it genuinely didn't matter. It matters enormously now.",[19,20,22],"h2",{"id":21},"the-arithmetic","The arithmetic",[15,24,25],{},"Take an 800-watt system on a west-facing Irvine balcony, tilted, open sky. It produces about 1,050 kilowatt-hours a year.",[27,28,29,45],"table",{},[30,31,32],"thead",{},[33,34,35,39,42],"tr",{},[36,37,38],"th",{},"Household",[36,40,41],{},"Share used at home",[36,43,44],{},"Value at 33.2¢",[46,47,48,63,76],"tbody",{},[33,49,50,54,57],{},[51,52,53],"td",{},"Someone home most days",[51,55,56],{},"75%",[51,58,59],{},[60,61,62],"strong",{},"$262",[33,64,65,68,71],{},[51,66,67],{},"Home a couple of days a week",[51,69,70],{},"62%",[51,72,73],{},[60,74,75],{},"$217",[33,77,78,81,84],{},[51,79,80],{},"Empty from morning to evening",[51,82,83],{},"45%",[51,85,86],{},[60,87,88],{},"$157",[15,90,91],{},"Same panel. Same balcony. Same city. Same weather. A $105 spread, which is 40 percent of the return, decided entirely by whether anyone's in.",[15,93,94],{},"Now compare that to the things people actually agonise over. Choosing a premium panel over a budget one might get you 5 percent more output. Adding a third panel to a two-panel setup adds maybe $60. Neither is close.",[19,96,98],{"id":97},"why-it-stopped-mattering-and-started-again","Why it stopped mattering and started again",[15,100,101],{},"Under the old net metering rules, exported power was credited at close to the retail rate. Your meter effectively ran backwards. Whether you used your production at noon or bought it back at 8pm was very nearly a wash, so nobody modelled it and nobody asked.",[15,103,104,105,108],{},"The CPUC's net billing decision in December 2022 changed that for rooftop solar, cutting export compensation to avoided-cost rates. And SB 868 goes further: it's silent on export compensation entirely, which means for a plug-in device, exported power is worth ",[60,106,107],{},"zero",".",[15,110,111],{},"So a kilowatt-hour you use is worth 33 cents and a kilowatt-hour you export is worth nothing. That's not a discount. That's the whole value of the thing, present or absent, depending on whether somebody happened to be running a dishwasher.",[19,113,115],{"id":114},"what-you-can-do-about-it-free","What you can do about it, free",[15,117,118],{},"This is the part that makes the question worth asking rather than just interesting.",[15,120,121,124],{},[60,122,123],{},"Move one load into daylight."," Set the dishwasher for 1pm rather than 8pm. Run the washing machine at lunchtime. If you have a timer on a water heater or a pool pump, move it. On a time-of-use plan you're shifting electricity from a 58-cent window to one where your panel covers it — worth roughly $60 a year for a single daily cycle, and it costs nothing.",[15,126,127,130],{},[60,128,129],{},"Pre-cool in summer."," Run the air conditioning harder at 2pm and let the house coast through the evening. Free, effective, and the house is more comfortable at 6pm.",[15,132,133,136],{},[60,134,135],{},"Charge things at midday."," Laptops, tools, an e-bike, a portable power station. Anything with a battery is a load you can move.",[15,138,139,142,143,108],{},[60,140,141],{},"Think about it before you buy a battery."," A battery is the equipment answer to this problem and it costs $800 to $1,500. Two timers cost nothing. Do the free things first, measure what changes, then decide. ",[144,145,147],"a",{"href":146},"\u002Fguides\u002Fbattery-or-no-battery","The battery decision",[19,149,151],{"id":150},"why-we-ask-it-in-the-wizard","Why we ask it in the wizard",[15,153,154,158],{},[144,155,157],{"href":156},"\u002Fwizard","Our calculator"," asks seven questions and this is the fourth. We phrase it as \"is anyone usually home during the day\" rather than \"what's your self-consumption ratio,\" because those are the same question and only one of them can be answered by a person.",[15,160,161],{},"It's also the question that most often turns a yes into a marginal, and occasionally into a no. A west-facing balcony with good sun and an empty flat produces a figure low enough that we'd rather you knew before buying than after.",[15,163,164],{},"That's uncomfortable for a site that earns commission on kits. It's also the reason to trust the number when it comes back high.",[166,167],"sources-block",{},"2026-09-01","Whether someone's home during the day changes your solar savings by up to 40%. It's the biggest lever in the model and no calculator asks about it.","md",null,"article",{},true,"\u002Fblog\u002Fthe-question-calculators-forget","Article",{"title":5,"description":169},[179],{"title":180,"url":181,"accessed":168},"CPUC Net Billing Tariff decision, December 2022","https:\u002F\u002Fwww.cpuc.ca.gov\u002Fnembt","blog\u002Fthe-question-calculators-forget",[184,185,186],"solar self consumption","does solar work if you're not home","solar savings work from home","The Solar Question Nobody Asks: Is Anyone Home?","KmegZR0RFNzszdpACIruJq48axadXAZvAk03mrASxEA",{"id":190,"title":191,"body":192,"description":217,"email":216,"extension":170,"location":218,"meta":219,"name":198,"navigation":174,"path":220,"photo":221,"role":222,"sameAs":171,"seo":223,"stem":224,"__hash__":225},"authors\u002Fauthors\u002Fmike.md","Mike",{"type":9,"value":193},[194,200,203,207,210],[15,195,196,199],{},[60,197,198],{},"Mike Yu"," started SmallSolarCo after working out that a plug-in panel was the only kind of solar available to him — he rents in Irvine with a west-facing balcony and no roof of his own. He is not an electrician, a solar installer, or a lawyer, and the site says so wherever it matters. He has a background building web products, and built the savings model here himself, using NREL irradiance data and Southern California Edison's published rates.",[15,201,202],{},"Since September 2026 he has been running a plug-in kit on that balcony and logging what it actually produces. Every measured figure on this site comes from that kit. Everything else is labelled as an estimate.",[19,204,206],{"id":205},"editorial-independence","Editorial independence",[15,208,209],{},"We don't accept review units on terms that involve anyone approving the review first. If a manufacturer sends us a kit, we say so on the review, and we keep the right to publish a bad one.",[15,211,212,213,108],{},"Reach him at ",[144,214,216],{"href":215},"mailto:hello@smallsolarco.com","hello@smallsolarco.com","Mike Yu started SmallSolarCo after working out that a plug-in panel was the only kind of solar available to him — he rents in Irvine with a west-facing balcony and no roof of his own. He is not an electrician, a solar installer, or a lawyer, and the site says so wherever it matters. He has a background building web products, and built the savings model here himself, using NREL irradiance data and Southern California Edison's published rates.","Irvine, California",{},"\u002Fauthors\u002Fmike","\u002Fimages\u002Fauthors\u002Fmike.jpg","Founder",{"description":217},"authors\u002Fmike","kb0uodhMlGk_YV3nMOIXdr6bpZgtB5zNoRxdGxsXMQ8",1788387858677]