EVANSDALE -- At the Harris Haven Funeral and Mortuary Haunted House, employees measure their attraction's success in decibels.

"When the screams start coming, that's music to our ears," said LeRoy Wilkes, a seasoned scarer.

The Evansdale spooktacular was one of several Halloween haunts to open its creaky doors to victims -- er, clients -- this weekend. And employees relished every shriek they were able to scare up.

"When you can hear the screaming and the laughing, we know we've done our job," said Pam Kabela, another Harris Haven fright-inciter. "There's just an electricity in the air."

But even if you missed opening night, there are still plenty more opportunities to add a frightened yelp to the chorus of howls echoing through the halls of Cedar Valley haunted homes. Throughout the month, Harris Haven and other houses of horror will be celebrating the season with terror-filled tours.

"Competition is great," Wilkes said of the region's haunts. "It's like trick-or-treating; no one wants to hit just one house."

At Harris Haven, guests step back in time to visit an abandoned funeral parlor. In the 1800s "unspeakable acts of horror" occurred on-site as the Harris family conducted experiments on townspeople in an effort to cheat death. The boo building is the brainchild of owner Gary Hall, who has been running haunted attractions for about 18 years.

"We don't have no Freddie, no Frankenstein, none of the generic," said Wilkes. "Ours has a theme from front to back."

The haunt opened in 2007. This year, the Harris Haven team has updated the attraction, adding more thrills and chills and a second pathway for guests to move through the home.

"We know that people want to see something new," said Kabela. "We want them to enjoy every second in our haunt."

The owners of Heart of Darkness in Waterloo strive to create a similar experience for their customers. This year the haunt's four buildings -- Scarecrow's Nightmare, the Slaughter Cabin, the Asylum and Scream in the Dark -- have been completely rebuilt. The attraction is twice the size it was last year, and on many nights, local bands entertain customers as they wait to enter the scare-fest.

"It takes some people a half-hour to get through," said owner Kevin Shults, who has been in the business for 12 years. "The haunt this year is honestly the best haunt I've ever assembled."

Motion-controlled devices and human actors keep visitors on their toes.

"I'm always studying the elements of fear so I understand how the human psyche deals with fear," Shults said. "With everything I do, I try to get inside their heads."

Contact Mary Stegmeir at (319) 291-1482 or mary.stegmeir@wcfcourier.com.

Dying to scare you

Harris Haven Funeral and Mortuary Haunted House

Where: 3767 Lafayette Road, Evansdale

When: 7 p.m., see Web site for dates

Cost: $8 adults, $5 children

More info: www.horridhollow.com

Heart of Darkness

Where: Heartland Farms, 5111 Osage Road, Waterloo

When: 7 p.m., see Web site for dates

Cost: $10

More info: www.entertheheartofdarkness.com

Waterhawks Haunted Hayride

Where: 100 Waterhawk Road, Evansdale

When: dark-11 p.m. Fridays and Saturdays; dark-9 p.m. Sundays

Cost: $6

More info: www.waterhawks.org