RICHMOND, VA (WWBT) - Freezing temperatures have plagued Central Virginia for more than 10 days now.
Heating systems across the Commonwealth are running on high.
That has fire crews and heating experts worried about malfunctions that could be deadly.
It's called the silent killer.
Carbon monoxide is an invisible, odorless, tasteless gas and is highly poisonous.
"Most people don't even know," said HVAC technician Gary Dedrick. "They'll get home after a hard day's work. They'll be sitting on their couch, enjoying a little time with their family. They're feeling tired. They think it's from the day's work and it's not."
It doesn't matter what type of system you use to keep your house warm in these chilly temperatures.
To avoid a carbon monoxide leak:
"Don't ignore your heating systems or your gas-powered appliances," said HVAC technician Sean Cantrell. "Have them checked out at least once a year."
The annual cleaning and maintenance will keep your system running as efficiently as possible.
"Lack of maintenance, you know, dirty filters are the number one killer of any system," said Dedrick.
Fire officials recommend you have a carbon monoxide detector in your home.
But our heating specialists say you should place it on a mantle -- not in a floor-level outlet, since carbon monoxide will rise at least four feet off the ground.
And watch out for signs of over-exposure including flu-like symptoms, headaches and fatigue.
"Family is the most important thing of all, so keep 'em safe," said Dedrick.
Fire officials remind you that you should never use a generator indoors, including in your garage, basement or crawl space -- even if there is ventilation.