There are a few factors that can help us determine this.
- Dust is blowing out of your ducts, or do they smell?
- A few things are known to set it off:
- The temperature in your rooms may be different from one room to the next, for example.
- Energy bills that are higher than expected because of seasonal changes.
- A foul smell may also be coming from your vents.
Only certain rooms in the building may be affected by a blocked air duct, rather than all of them. As a result, your HVAC system will have to work harder to adequately cool or heat that room, increasing your energy bills.