Heat lamps aren’t enough to keep outdoor dining going into the Northeast’s cold weather, says the owner of The Red House in Harvard Square. (Photo: Marc Levy)

Heat lamps alone won’t be enough to keep local restaurants serving outdoors, according to a Cambridge restaurateur with years of experience in al fresco dining. But restaurants have been counting on outdoor dining space to keep their revenue high enough to survive another winter likely hobbled by a pandemic.

With social distancing and other coronavirus-enforced restrictions, Harvard Square’s Paul Overgaag said his Red House restaurant is doing 40 percent to 50 percent of the business it did in past years, and his Charlie’s Kitchen is doing just a tenth of the business. Like many restaurant owners, he’s been thinking a lot about what happens when summer’s warmth is gone altogether – especially since Gov. Charlie Baker’s order allowing expanded sidewalk and street dining ends Nov. 1.

And he’s worried.

“Unfortunately, New England is too windy for heat lamps. The heat just disappears,” Overgaag said in a phone interview.

His conclusion is based on outdoor dining experience going back decades to Giannino’s, the restaurant he once ran in the courtyard of the Charles Hotel, where he piped in gas to heat lamps that simply failed to keep customers comfortable.

“The Red House has had an Australian-made outside umbrella with heat lamps in it – that doesn’t work. The patio at The Red House has radiant heat – that doesn’t work,” he said. “We had an open pit fireplace at Charlie’s that the fire department made us take out, and that was the only thing that worked because it was a visual thing. People like a visual fire. It makes them feel warm.”

“I’m sorry for the negativity, but heat lamps are just not enough BTUs to make you actually feel warm,” Overgaag said. “You need to see the thing.”

Restaurant owners have been trading tips in online groups, with the consensus being that tall propane heaters with the mushrooming tops are the best and most cost-efficient. But with socially distanced spacing of at least 6 feet between tables, you’d need one per table, the thinking goes. While that will save on propane costs, there’s a risk of thousands of restaurants on the East Coast all seeking heat lamps at the same time – with demand likely dropping off a cliff when November arrives.

At that point, what happens is anyone’s guess. A Monday post in The Dig by food writer Marc Hurwitz runs through eight options for restaurants for the winter. But the final one is to “pray for a miracle.”

Overgaag’s plan at The Red House, 98 Winthrop St., is to enclose the patio, which would raise the number of socially distanced customers he could serve in the winter to possibly as many as 47 from 20. The plan needs to be approved by the Historic Commission. “If I have that front area where I can keep seating,” Overgaag said, “I have a chance of making it through the winter without losing a ton of money.”