We have another cold day ahead of us, with temperatures starting off in the low 20s and creeping up to the mid-30s. I’m Felicia Gans Sobey, a digital editor at The Inquirer, and I’m filling in for Kerith today.

Today we answer some commonly asked questions about at-home COVID-19 tests and how to use their results.

Also, we take a look at the region’s shrinking housing supply.

— Felicia Gans Sobey (@FeliciaGans, morningnewsletter@inquirer.com)

It’s never been easier to get your hands on an at-home COVID-19 test. With the government offering to send four free tests per household and insurance companies covering up to eight a month, all that’s left is knowing how to use them correctly.

Are the rapid at-home tests reliable?

Antigen tests have a sensitivity of 80% to 90%, studies show, so if you get a positive result, it’s pretty likely you have COVID-19. But false negative results are more common with these tests, so a negative result doesn’t necessarily mean you don’t have the virus.

So what do I do if I get a negative at-home test result?

If you’re symptomatic, have had an exposure, or were in a high-risk environment, you should isolate for two days and then take a second at-home test. If the second is also negative, it’s more likely that you’re actually negative.

How much will this cost me?

The tests mailed out by the government are entirely free. The rest gets a bit more complicated.

Insurance companies will cover eight tests per member per month — but only up to $12 a test. You pay the rest. PCR tests are generally free, but there are some exceptions. Insurers can technically deny covering a test if it’s for someone without symptoms (but in practice they probably won’t).

“Clear as mud, right?” says Sabrina Corlette of the Center on Health Insurance Reforms at Georgetown University.

Our reporters Jason Laughlin and Sarah Gantz answer more of your questions.

Buying a home is already hard enough. But with the housing supply continuing to shrink, prospective buyers in the Philly area have even fewer options than they did last year.

The numbers tell the story.

Our reporter Michaelle Bond has more on the state of the housing market.

Philly is getting a fantasy-themed bar-restaurant, and it could open as early as this spring. Its founders say it’s not endorsed by, affiliated with, or associated with Warner Bros., J.K. Rowling, or J.K. Rowling’s Wizarding World. But our reporter Michael Klein says Harry Potter would feel right at home. Today’s Question: What will the bar be called? Find the answer here.

a. Wing-BREW-dium leviosa

b. Draco’s Den

c. The Cauldron Magical Pub

d. Butterbeer Manor

That’s all for today. Kerith will be back in your inbox tomorrow.

Have a great day, Philly. 👋