David Jackson thought he was called to a home in Conroe to repair the heater.
"Busy time of the year for ya huh," an undercover FOX 26 Investigates producer asked Jackson upon his arrival.
"Yea," Jackson replied.
But according to the Texas Department of Licensing and Regulation Jackson shouldn't be busy working on heaters and air conditioners because he doesn't have a license.
"Without a license the state can come in and order a cease and desist," said Susan Stanford with the state's licensing department.
And state licensing officials have one of those orders against Jackson.
"Yes," Standford said. "There is a cease and desist order against David Jackson."
But it sure looked like Jackson wasn't abiding by that order.
"How long have you been doing this?" the homeowner asked
Jackson who replied, "All my life."
But the state has no record of Jackson ever having or even applying for a license. Candy Martin said she found out something even more troubling about Jackson.
"We had a really strong odor of natural gas in our master bedroom," Martin said.
According to complaints filed with the Better Business Bureau, the Texas Attorney General's Office and the Montgomery County District Attorney's Office, Martin paid Jackson 12 hundred dollars for a new heater.
"He told me that the unit in question, the downstairs furnace had a cracked heat exchanger and that there was no way to repair it the entire unit had to be replaced" Martin said.
Martin's complaints allege Jackson didn't really install a new heater, he just applied sealant to the old one.
"And stuck a Coleman sticker on the door to disguise a York furnace," Martin said.
Martin's friend Ann makes the same disturbing allegation in her criminal complaint against Jackson. That he charged her 12 hundred dollars for a new heater but did nothing more than apply sealant to her old one.
"I was furious to say the least," Martin said. "Because in this day and age no one can afford to just throw away 12 hundred dollars."
When FOX 26 Investigates confronted Jackson about his license, he claimed to have one. Jackson showed us an invoice with a license number but we later found that number doesn't belong to him.
FOX 26 Investigates also asked Jackson about the allegations his two customers are making about making their old furnaces appear to be new. Jackson didn't answer us. Instead he drove off.
While Jackson is now the target of a criminal investigation, currently there are no criminal charges filed against him. Through court records we found Jackson is serving deferred probation for writing hot checks to purchase heating and air conditioning equipment.
Even though Jackson had nothing to say to us, Candy Martin has plenty to say to him.
"You may have stolen that money from me and I hope you enjoyed it because I can sleep at night. I don't have things weighing on my conscience that I'm taking advantage of people," Martin said.
State officials urge all consumers to check it's website to ensure the person working on their heaters or air conditioners is licensed to do so.
-- Visit the Texas Department of Licensing and Regulation: http://www.license.state.tx.us/LicenseSearch/