Gohn & Stambaugh technician Joe Emenheiser services a gas furnace at a Spring Garden Township home.
Gohn & Stambaugh technician Joe Emenheiser services a gas furnace at a Spring Garden Township home. (Bill Kalina photo)

As if lacking in reasons to be the object of scorn, the invasive brown marmorated stink bug is giving Yorkers another cause for contempt.

The little shield-shaped stinkers, looking for warm places to hibernate for winter, are crawling into heating units and causing sometimes-costly service calls as people fire up their furnaces for the first time this season.

The winged bugs invite attention each fall as they clamber up the sunny exterior walls of houses and buildings to bask in the warmth, said Barbara Stewart, master gardener at the Penn State Cooperative Extension in York. It's also the time of year they're seeking cozy places for a long nap before they get back to breeding, a task which they managed to perform at least twice -- maybe three times -- this year because of the warm spring, she said.

So there are a lot of them, as Ben Stambaugh, vice president at Gohn & Stambaugh Inc. in Springettsbury Township, can testify.

"I've seen them crawl into HVAC systems and cause trouble," he said. "They don't survive in there. They pile up. I've seen half of the housing clogged with them, (they have) been in the hundreds inside these things."

While some might suggest a dead stink bug is the better version of the bug, they might consider location. They might also consider that familiar odor warmed and circulating.

"Obviously when they get into the duct work, they die and they stink," he said. "I would say one out of five guys on maintenance has a stink bug somewhere (in the customer's heating system) that needs to be removed."

The presumed port of

entry is the two-or-three-inch PVC pipes used for exhaust and air intake in the heating systems.

Technicians who perform annual maintenance on units can discover and remove the bugs before the system is activated, but those inside the unit when it turns on can cause problems, said Matthew Miller, service manager at Dutch Heating Inc. in York City.

"They're getting into the burners in the furnaces," he said. "Either the unit won't work at all or it affects efficiencies and could cause damage over time."

His crews are called to a stink bug problem about once or twice per week, he said, because homeowners report their furnaces are either not working, are "rattling," or "There's something different from the previous year."

"Most of the time they'll laugh and snicker about it, but they're disappointed it required a service call that's going to follow with a bill for what's basically a pest invasion," he said.

Bills could range from between $100 and $300 depending on the damage. The cost for an inspection before starting a heating units ranges from $65 to $85, he said, and people shouldn't try to take apart their furnaces unless they know what they're doing.

"The average homeowner knows how to change the filter, and beyond that, when you're dealing with products of combustion, guesswork is not a good option," he said.

Tough buggers: Stewart said there's no extermination product that works on stink bugs, though researchers at universities such as Penn State are working to develop one.

For now, she recommended making sure homes are well-sealed and drowning any invading stink bugs in dish detergent.

But there are some potential portals that can't be sealed. Stambaugh and Miller agreed that the intake and exhaust pipes can't be blocked with something, such as a screen, small enough to keep out stink bugs without risking damage to a furnace.

"The tough part is you can't cover it or it will freeze in winter and your furnace wouldn't work," Stambaugh said.

He recommended annual inspections, and that might be a good idea in the spring as well.

The bugs have been found in air conditioning contactors, a device like a light switch, Stambaugh said.

"When it snaps closed, it smashes them and they die, but their shells have an insulating property so they don't pass voltage so (the contactor) doesn't conduct," he said. "They don't come back out very easily. They arch and char and the contacts get pitted."

Because of the damage, people often need to purchase a new contactor for between $85 and $105, he said.

-- Reach Christina Kauffman at ckauffma n@yorkdispatch.com.