HOUSTON -- Note: The following story is a verbatim transcript of an Investigators story that aired on Tuesday, Dec. 9, 2008, on KPRC Local 2 at 10 p.m.

Tonight, Local 2 Investigates uncovers who's leaving the lights on inside government buildings. We found empty city and county buildings in downtown Houston are being lit up like Christmas trees night after night. Not only is it not "going green," it's costing taxpayers a lot of it.

Local 2 investigative reporter Amy Davis uncovers where it's happening and why it took our investigation to get your government to turn off the lights.

At 3 a.m., your house and your neighbors' homes are likely dark. Downtown Houston even appears nearly deserted. However, it's not as dark as you might imagine. We found the lights on inside empty government offices. It's electricity you're paying for each month. We uncovered you're even paying to power flat screen TVs all night when no one is watching.

It's a problem no one knew about until Local 2 Investigates burned the midnight oil. For weeks, we checked out city and county buildings downtown overnight on both weeknights and weekends. We're shining the light on who is wasting electricity while you're footing the bill.

Seventy-one thousand tax dollars each month goes to pay for electricity at the Houston Public Library downtown. After 3 a.m., it looks like the library is open for business. We found the bottom floors lit up and even the flat screen TVs running with no audience to entertain. It's a scene we witnessed all night long, morning after morning.

It's the same story at the Harris County Family Law Center. From hallways to storage areas to individual offices, we found all of the lights left on every time we checked -- even early on a Sunday morning. The electricity bill for the building costs you about $17,000 a month.

Down the street at 611 Walker Street, we noticed lights on inside about a dozen floors of the city of Houston's 26-floor Bob Lanier Public Works Building. The same floors were lit up all night long each time we checked -- both during the week and on a Saturday night. The electric bill for the building runs a little more than $133,000 a month.

"It's really everyone's problem," said Andy Bergman, an organizer for the Lights Out Houston event and vice president of Air Zone International in Houston. "You've got to hit people close to home, in their pocket books."

Bergman discovered lights were being left on inside private office buildings earlier this year. He helped start Lights Out Houston, where companies pledged to turn out the lights over one weekend in April. Bergman projects if the same buildings made half that effort year round, they would save more than $4 million a year.

"It's not rocket science. It's the simple flick of the light switch, but what we realized was is we're dealing with changing habits analogous to quitting smoking or going on a diet," said Bergman.

But you don't pay the bills for those private buildings. Your money is spent when the lights are left on inside those city and county buildings. We wanted to know why Houston and Harris County are wasting it.

"A lot of times, people just forget to turn the light switch off," said Soumya Rege, chief operations manager for Harris County facilities and property management.

Rege oversees the operations of Harris County buildings, including the Family Law Center. She says the building was built in 1966 and it would cost too much to install new lights that would turn off automatically late at night, but Rege admits that's no excuse.

"We consider something like this a serious problem because our goal is to maximize energy savings," said Rege. "So anything we can do help in the energy efficiency of our buildings, we'll go out and do it."

"We have a problem," said Issa Dadoush, director of the city of Houston's General Services Department. We want to thank you for bringing this to our attention because we are leading by example."

Dadoush oversees the electricity usage at all city buildings. He says the lights we saw on at the Lanier building should have been turned off well before 3 a.m. -- after those offices are cleaned. The downtown library closes at 9 p.m. Cleaning crews work inside the library all night, but Dadoush says they don't need every light on while they clean.

"We take energy conservation very, very seriously over here. If this is an issue, we're going to address it and take care of it," he said.

Clearly, it's a pretty easy fix. Just one day after we spoke with the city, all of the lights that were left on inside the Houston Public Library were turned off overnight. The cleaning crews were still working, but entire floors are now dark -- including all those TVs. There was also a huge difference at the city's high rise Lanier building. All of the dozen floors that once had lights on are now dark overnight.

However, it was a different story at the county's Family Law Center. At 3 a.m. the day after our interview with Rege, the lights were still left on. Remember, the electric bill for the building costs you $17,000 a month. The county estimates it could save around $1,100 every month by just turning off most of the lights overnight. That's if the county makes the effort. In this case, time is your money.

"I can't honestly answer the question about how long this has been going on up until now," Rege said. "I can tell you that we'll make sure things like this don't happen again."

We did call Rege back to ask when the county plans to start the simple fix of switching off the lights.

The Houston Public Library initially told us it was not turning off all the TVs overnight because they were looking for a software program they could buy that would do it for them. Since we called, they say they'll just do it manually until then.

Although some lights were left on, the city says it has cut its overall energy usage by 6 percent in the past five years. That drop in usage continued despite adding many more city buildings during that time. Dadoush also adds that all city buildings have automatic cut-offs for air conditioning units, and most buildings have lights that automatically shut off at 11 p.m.

What have you seen? Did we miss a government building wasting power? Let us know.