Most scammers aren’t thoughtful enough to use red flags on their logo, so you’ll have to figure out these warning signs on your own.

—You cannot verify the name, address, phone number or other basic info or credentials about the installer:If you can’t find the contractor on Google, Yelp!, Angie’s List or any other professional directory, there’s probably a good reason—they’re fake. Reputable companies are listed in numerous indices. Some even still use the phone book.

—You feel pressured to pay upfront, in cash, and/or without a contract:No, no, and no. Reputable contractors follow basic business principles. Never put more than 10% down on a project, always pay using a method that creates a record (check, PayPal, etc.), and never let someone start work on your house without a contract. 

—The price is too good to be true:Some rates—like a $100 flat instillation fee per room—don’t leave any space for profit, and, just like you, a contractor has to make a living. Be wary of offers of “free materials” (they could be stolen) or labor charges that don’t even meet the federal minimum wage. 

—No references: If they hem and haw when you ask for references and never get around to providing you any names or phone numbers, that means either they don’t have any previous clients to vouch for them, or worse, no one they’ve ever done work for has anything good to say about them.

—They’re impossible to get ahold of: Not only should a contractor be able to give you contact information for former clients, they ought to be reachable with the phone number and email address they provided for themselves as well. If you’re always calling and leaving messages after an indistinct, generic voicemail greeting—and they’re always calling you back from a different number—they could be hiding something. Like their identity. 

—They can’t give a straight answer to simple questions: Construction work can get pretty complicated, but it still ain’t rocket science. A reputable contractor should be able to answer your questions in plain language you can understand. Don’t let anyone baffle you with BS.  

—They aren’t good listeners:You want an installer who is going to listen carefully to what you want and give you several options that suit your needs across several price points. If you feel you’re being ignored, and only the “premium” options are being pitched, the installer is neither valuing you as a homeowner nor respecting you as a paying customer.

—No portfolio: Quality professionals like to brag about their work. If the installer doesn’t have a portfolio, either a physical book or an online gallery, highlighting the very best they’re capable of, that means they don’t have anything to be proud of. Find someone who does.

—Too many one-star ratings:You can’t make everyone happy all the time, so the rare one-off bad review may not indicate anything more than a client who couldn’t be pleased. But too many bad reviews, and a low average rating, are the telltale signs of an installer who needs to think about a different line of work.