What to know
Ask what portion of the system is included
Some quotes cover the accessible runs. Some cover the supply side only. Some cover everything reachable including the returns and the boots under each register.
Those are different jobs, and the difference in scope explains most of the difference in price. Get it in writing before comparing anything.
Ask what happens when they find damage
Sealing assumes the ductwork is intact enough to seal. If a run turns out to be disconnected, crushed, or too far gone, what then?
A good answer is that they stop, show you, explain what it changes, and let you decide. A company with no answer to that question has not thought past the sale.
Ask to see the ductwork
Before and after, in your house, not a stock photograph. Anyone doing genuine work can produce it, and reluctance at this exact point is the most useful signal you will get.
Things worth comparing
- Whether anyone inspected before quoting, or the price arrived over the phone.
- How much of the system the figure covers, in writing.
- What the plan is for runs that are damaged rather than leaky.
- Whether the person quoting is the person doing the work.
- Whether they will tell you when sealing is not the right answer.
The answer that tells you most
A company that will explain when you do not need the work is showing you the thing you cannot verify any other way. It costs them the job to say it, which is exactly why it is worth listening for.
Where to start
Which of these applies to your house is not something a page can tell you. It depends on how the ducts were built, what has been done since, and how much of the system is reachable.
Our inspection is free. We will show you what we find, and if the ductwork is sound and simply needs cleaning, that is what we will say.