There are certain qualities that a good replacement window company should have and if these area not available chances are you are dealing with someone who will scam you. Below I provide a quick list of these:
Certification and licensing
Replacement window contractors are expected to have a certificate that allows them to operate in an area. A scammer can produce some forged certificate to prove that they are both certified and licensed to do business in your area. You need to follow up and check with the relevant authorities before you hire any one. If a company is not certified then there must be a reason, which should tell you not to hire them.
Membership
If you've ever hired a contractor before then you know that they always boast of being a member to a certain industry association. They all know this is key because being a member means you are at a certain "better" level that your competitors. Now a ruthless company will present false information on this just to get them to commission them to do the job
Someone else's portfolio
If you've ever read some of my reviews then you know that I always recommend checking out some previous jobs done. This puts you at ease as you see the kind of job the replacement company can produce. These companies know this and may "steal" other companies' portfolio and show it off as theirs.
Expensive quotation
This is an obvios way to be scammed. I've had a contractor produce a quotation and told me it was the cheapest in the area. He spoke to convincingly I believed him and never bothered to get some more quotations from other companies. Need I say what unfolded.
Add on on quotation
Sometimes you'll get them to provide a quotation, you double check it with others and choose it as the best. After you sign the contract unscrupulous window replacement companies will then tell you that they have to requote and will give you a thousans confusing reasons for requoting. This is why you need to make sure that a potential contractor inspects your home and ascertains the exact costs before you sign anything.