PITTSBURGH (KDKA) – A word of caution this morning: take action now or you could end up a bit chilly when the truly cold weather finally arrives.

When the hard freeze hits it always reveals problems in home heating systems.

READ MORE: Jackpot-Winning Lottery Ticket Worth $1.75 Million Sold In Indiana County

“The first day we get cold weather, our phones will be ringing off the hook, and we’ll be booked up for three weeks,” says Rocco Florio of Air Pro Heating and Cooling.

Florio says your unit may have been fine all summer, but cool in the summer does not guarantee heat in the winter.

“There are a lot of electronics in furnaces like igniters flame sensors that get dirty igniters that go bad, which you wouldn’t use in the summertime because you’re using it just for the air conditioning,” he says.

Florio says the first thing you should do is change your filter.

A dirty filter slows the airflow.

“Without the airflow, it’ll shut right down,” he says. “It’ll kick off on the limit because you’re building up too much heat in there.

He says replace one-inch filters monthly during the heating system. The more technical stuff inside the furnace he says should be checked out at least every other year.

If you call someone into your home he says beware of upselling.

“Basically, your furnace was working fine last season and they start talking about you know, you have this problem and your bills getting upward of $900, you got to call somebody else,” he says. “I mean, get a second opinion.”

WATCH: Beware Of Upselling, Hidden Fees

Caitlin Driscoll from the Better Business Bureau says nationwide, they have had 2.5 million inquiries about the HVAC industry in the last year.

“We also processed over 3,000 complaints regarding this industry,” she explains. “Common types of complaints, typically include substandard work. Another issue with contractors who never finish the job that they start, as well as an issue with billing for expenses that weren’t discussed with the homeowner upfront.”

She says check out the contractor on the BBB website before hiring them.

READ MORE: COVID-19 In Pittsburgh: Allegheny County Reports 3-Day Total Of 989 New Cases, 11 More Deaths

Then, ask a lot of questions because fees often go beyond that advertised price for a clean and check.

For instance, she says some are “charging what’s called a trip fee to help offset their travel expenses, and then they charge for their actual service.”

And that’s not all.

“Some contractors may also even charge a diagnostic fee that could cost you hundreds of dollars before they even do any actual work,” Driscoll says.

Ask if they are charging an hourly or flat rate.

Driscoll says just because they offer 24-hour service, “that doesn’t necessarily mean that you won’t pay a lot extra for those types of times, as opposed to just a normal service.”

None of those charges are illegal, but if you don’t ask they can be a surprise.

“Get everything in writing, any type of agreement, any type of information regarding payments, any warranty information.”

Also, note if your provider starts talking about delays in getting some major parts that may very well be legit.

Florio says for some of the bigger parts, or assembled units.

“It’s about a two-to-three-week wait for you know, getting this equipment,” he says.

Driscoll says, “it’s a quite unfortunate issue for both consumers and the businesses and being able to obtain the supplies in order to get the jobs done.”

And Florio warns, “the more we go into the season that we’re going to see this get worse before it gets better.”

MORE NEWS: COVID-19 In Pennsylvania: State Reports 3-Day Total Of 10,412 New Cases, 73 More Deaths

Which is another reason to get your furnace checked before the cold snap that is just around the corner.