One tiny grace for retailers during the coronavirus outbreak has been that it didn’t strike during a peak selling period like the holiday season. There’s one notable exception: the $900 billion home improvement sector, led by Home Depot and Lowe’s.

Spring for home improvement stores is by far the busiest time of year, generating about 30% of annual sales, as people catch up on things like replacing bathroom tiles, installing new kitchen cabinets, and repaving the driveway after winter. The spring season is to Home Depot and Lowe’s what the Christmas period is to Macy’s or Best Buy.

The home improvement retailers were among the lucky ones deemed essential, enabling them to stay open. And business was brisk in March, helped by millions of people working from home.

“People are home and trying to get projects done around the house,” says Shelley Kohan, a professor of retail management at the Fashion Institute of Technology.

Lowe’s CEO Marvin Ellison told Fortune last month that customers were snapping up appliances like freezers to store food for lengthy periods and buying cleaning supplies. And U.S. Commerce Department figures reflect a surge in March for home improvement stores: Sales of building material and garden equipment rose 7.6% last month.

But, as is the case with other retailers, notably Walmart and Target, the need to prevent the spread of the virus has now led them to take steps that could put the brakes on that surge.

For instance, stores large and small are limiting shopper traffic, from a tiny Sherwin-Williams paint store on Manhattan’s Upper West Side only allowing sidewalk order pickup to Home Depot’s 100,000-square-foot big-box stores keeping the number of customers to 100 at a time. Lowe’s is also monitoring store traffic.

What’s more, Home Depot has left a lot of business on the table by going further than any other major retailer when it said in early April it would not hold “major spring promotions to avoid driving high levels of traffic to stores.” That would be like Walmart saying, no Black Friday doorbusters.

And Home Depot is paying a price for that: Data from Placer.ai, a tech company that tracks store traffic, found that on April 14, for instance, visits to Home Depot were down more than 20% for the equivalent day in 2019.

But the move is consistent with Home Depot’s long-term outlook, which has served it well, analysts say. “That makes customers feel safe and shows empathy for how [the] consumer is feeling,” says Kohan. “That builds tremendous loyalty right now.”

Plus, she adds, it’s good for employee morale.

Lowe’s, whose sales growth has lagged its larger rival Home Depot’s for years, is taking a different tack. While it is pulling back on some of its marketing, it is not dropping sales events altogether, likely sensing a market share opportunity.

“Affordability matters now more than ever,” a Lowe’s spokeswoman says. Placer.ai found Lowe’s traffic has risen.

More pickup options

Both Home Depot, which last year took in $110 billion, and Lowe’s, with sales of $72 billion, have rushed in the past few weeks to provide curbside and drive-up pickup of orders at nearly all their U.S. stores to mitigate lost sales. Home Depot, in particular, is an e-commerce powerhouse, with digital sales up 20% last quarter. Lowe’s has lagged far behind but is overhauling its e-commerce.

“Customers will reward any retailer that makes it really easy for them to buy on their phone and pick up in store, so that’s an advantage,” says Joel Rampoldt, a managing partner at AlixPartners.

Drive-up and curbside pickup give shoppers additional options, but they inevitably harm impulse sales that happen in store, such as that pillow you hadn’t planned on purchasing but tossed into your cart as you walked by.

Home decor is the kind of impulse category Home Depot has waded into more recently to get more revenue per customer visit, something at which it excels. Despite its meteoric sales growth since the last recession, it did not open many new stores. It hasn’t needed to: Sales per square foot rose 63% to $454.82 between 2009 and 2010.

So far, six weeks into the pandemic’s spread in the United States, demand seems to be holding up relatively well for the home improvement retailers, analysts say. Appliances are selling, and people seem focused on renovations, all the more since so many other expenses like travel and restaurants are being cut.

“Big do-it-yourself projects will really prosper at the expense of vacations,” says Rampoldt.

Of course, the lockdown could affect projects that might require professional expertise. Restrictions may limit renovations in apartment buildings, and some may not want to invite others into their home. Some 46% of Home Depot’s business comes from professionals, and 20% or so at Lowe’s.

Still, barring any meltdown in the the housing market, there are tailwinds for these stores. “The massive wave of home refinancing, spurred by historically low rates, may mean increased maintenance and remodeling activity,” Bloomberg Intelligence wrote in a research note this week.

And FIT’s Kohan says, so far, results bear that out: “People are investing in their homes.”