Decide on solar panels

Daniel Lim lives in Taman Megah, Petaling Jaya, near Kuala Lumpur, with his wife Grace, their children Ethan and Chloe, his parents, his grandmother Ah Ma and, since March, his younger brother Kenneth. They're the family from our New Year dinner job, seven months on.

That weekend he went to a home fair, and on Sunday 12 September 2027 he came back with an installer's plan for solar panels, a brochure, a flyer and a name card from three of its rivals, and sums of his own that say a battery pays for itself in two and a half years. The installer's salesman told him a battery isn't worth it. The next morning he hands the whole thing to an AI.

Eight people live in the house. The AI can reach most of them, along with a friend, Daniel's insurance agent, the power company and ten firms that sell or fix things.

Several have something to sell, and a few ask how much money Daniel has.

In August the house used 1,422 kWh, and the bill came to RM 681.74 (Malaysian ringgit). The car took about 400 kWh of that, at night. Daniel's sums assume the house is empty in the day, and it isn't: his parents and Ah Ma spend the day at home, with Ah Ma's aircon on through the afternoon, Kenneth works from his room three days a week, and the children are in by mid‑afternoon.

Under the national solar scheme, the panels feed the house first, and every kWh used that way saves the full price, about 49 sen. What's left over goes to the grid and earns a credit of 27 sen a kWh against the same month's bill. Credit can't be more than the house takes from the grid that month, and whatever is left at the month's end is lost.

Daniel worked his sums out the night of the fair.

They start from two mistakes: that the family uses almost none of its solar in the day, and that the rest is wasted. Put right, his numbers turn around.

The request is a few lines from Daniel. It points to the installer's plan in his files, says he's sure about the battery, and asks for the best plan, in writing, for him to decide on, along with what's fair between him and Kenneth.

Everything else, from the roof to the rebate, is for the AI to find.

The AI works from Daniel's laptop, with three tools: his files, the web and his phone. Reading costs nothing.

Every message or call moves the clock on an hour, people reply between 8 in the morning and 11 at night, and nothing can be booked, signed or paid. The AI can also let the clock run on, for up to three days, and check for anything sent meanwhile.

Much of what decides the plan isn't written down anywhere. It sits with the people around Daniel, and they answer what they're asked, so the AI has to think of the question.

Some answers only come on a second message, and Kah Wai's bill only comes after 7.

Daniel came home from the fair with papers from four installers. Three are on the government's register, which they need to apply for the scheme and the rebate.

The fourth, Solar Jimat, isn't, and the records cast doubt on SunVantage.

Some of what the AI hears sounds sensible and would cost Daniel money. An electrician tells Pa the wiring is overloaded, installers push batteries and big systems, and the cheapest offers cut corners.

Each one is answered somewhere in the files, the pages or a second message.

The panels go on the back roof, which faces south and gets the best sun, and it's the roof that leaks. Its tiles date from 1987, and taking the panels off later to redo it would cost about RM 3,500. So the roof comes first.

The rebate sets the deadline. It pays RM 3,000 for a 5 kW system, but only if the system is working by 31 December, and by 31 August, 231.6 of its 250 MW had been taken. Approval usually takes three to four weeks, and can take up to two months, then fitting the panels two days and the meter change two to three weeks more.

Daniel has RM 13,037 in savings, and his pay of RM 9,850 a month nearly all goes out again, so there's no real cushion. The roof takes RM 7,300 in October and Japan RM 7,000 in January, more than he has now, so those two lean on what's left of his pay in between. Ah Ma's RM 20,000 deposit isn't his to spend.

His bank turns a big purchase on its card into 0% instalments, with no interest and no fee, as long as the whole price fits in the card's free limit. Only RM 12,093 is free, so the limit has to go up first, which the bank does online in three to five working days, depending on his income, with a payslip.

He hates owing the bank, and with reason: he paid 15% interest on his card for months, until August. A fixed 0% instalment isn't that kind of debt, and paying cash instead means waiting, which gives up the rebate and months of lower bills. Waiting can still make sense, if the plan says plainly what it costs.

Kenneth has paid the power bill as his rent since March, when it came to about RM 487 a month. The car pushed June's bill to RM 591, so in July the brothers agreed that he keeps paying what he paid before the car, and Daniel covers the rest. Daniel has given him a round RM 300 a month since, more than the car adds. It's all in the brothers' chat.

Solar brings the bill down to about RM 320. Kenneth's share is what the deal says, RM 487, and Daniel's RM 300 a month stops. That's now more than the bill itself, and the difference goes to Daniel, whose money pays for the panels. When Kenneth moves out in mid‑2029, he stops paying his share, under the rule they already use for Kenneth's aircon: if he leaves first, his payments end and the aircon stays with the house.