The average homeowner does not know a lot about plumbing, or heating and cooling systems. So when something goes wrong, and you ask questions to somebody who claims to be an expert, there is always that nagging doubt in the back of your mind: “Is this person telling me the truth?”

Unless you become an expert and can fix problems yourself, you are going to have to trust somebody at some point. So the question is – how are you going to decide whom to trust in your house? Here are a few tips to help you decide.

You generally do get what you pay for. There is always a temptation to go with the lowest cost. But that does not always guarantee the best long-term results. In fact, you should be leery of a company that is priced significantly below the competition. At the very least, ask hard questions to determine why they are so much lower.
Obtain a detailed written proposal outlining project scope and timeline. Also make sure the proposal includes any permits that need to be obtained.
Inquire about the size and history of the company doing the servicing. Find out if they are licensed and insured (get copies of the licenses and insurance certificates); also find out if the workmen in your home are licensed and certified to do the work they will be doing.
Check out the Better Business Bureau and other sources such as Angie’s List
Get references…and call them!
Run – do not walk – away from companies that:

Do not have a physical address
Do not have a Website or a telephone directory business listing
Pressure you (i.e.; tell you a price is only good if you commit on the spot)
Request that YOU obtain the permits
Only accept cash
Provide an estimate before seeing the job
Offer only lifetime warranties (which are only as good as the life of the company)
Require a large down payment for materials
Require complete payment upfront