The Fourth of July fireworks have popped, leaving clods of burnt paper on the lawn. Summer is here in earnest. For some, this is a joy. For the rest of us, it’s a sluggish, enervating purgatory of too much heat and forced frivolity. It’s the perfect time to turn up the air-conditioning way too high and waste time (and electricity) watching “Big Brother” (8 p.m., CBS).

I don’t exactly like “Big Brother.” In fact, the exaggerated, sleazy behavior of dim bulbs tends to depress me. But I appreciate it as a perfect symbol of the slightly sour days of summer and its role as a constant companion to the vaguely decadent summer shut-in. What other show expects people to reject the “nice” weather and sit inside and watch other people who also can’t leave the house. Or don’t want to. It’s a show about shut-ins for shut-ins! So short of a “Hoarders” marathon, it’s just about perfect viewing for some.

And this year they’ve changed the house. According to CBS, it’s a “loft inspired” (whatever that means) structure featuring an “urban” design that “brings the outdoor decor in and the inside decor out.” Huh? So will host and super-serious news journalist Julie Chen be conducting her in-depth interviews inside or outside? Does it really matter?

But don’t worry. Some contestants will still be banished to the “Have/Have Not Room,” which is not a very nice room at all.

• Some business names are so iconic that you forget they’ve been associated with real people. “Titans” (8 p.m., CNBC) profiles an English candle maker and an Irish soap maker who met in the 19th century and combined to create the most powerful consumer goods company in history. William Procter and James Gamble could never have envisioned the worldwide clout of today’s Procter & Gamble, but in interviews former CEOs John Pepper and A.G. Lafley and current chief executive Bob McDonald describe how the huge company strives to remain innovative.

Tonight’s other highlights

• Two get the hook on “So You Think You Can Dance” (7 p.m., Fox).

• “An American Family: Anniversary Edition” (7 p.m., PBS, check local listings) offers two hours of clips from the innovative 1973 series that marked the birth of reality television.

• Loan shark worries on “Burn Notice” (8 p.m., USA).

• A secret is revealed on “Love Bites” (9 p.m., NBC).

• Several severed heads go missing from a lab on “Rookie Blue” (9 p.m., ABC).

• Mike needs help on “Suits” (9 p.m., USA).

• Spencer is enraged on “Wilfred” (9 p.m., FX).

• House-hunting on “Louie” (9:30 p.m., FX).

Cult choice

Director Paul Verhoeven’s 1997 satire “Starship Troopers” (8:45 p.m., Encore) takes a jaundiced look at jingoism and wraps it up in a soap opera about war with a race of alien insects.