Determining if your HVAC system is sized incorrectly for your house typically requires a professional load calculation. However, there are a few indicators that can give you a rough idea:

1. Short Cycling: If your HVAC system frequently turns on and off in short cycles, it may be oversized for your home. Short cycling occurs when the system quickly reaches the set temperature and shuts off, only to start again shortly afterward.

2. Inadequate Cooling or Heating: If your HVAC system struggles to cool or heat your home adequately, it may be undersized. You may notice uneven temperatures, rooms that take a long time to reach the desired temperature, or the system running continuously without achieving the desired comfort level.

3. High Energy Bills: An oversized HVAC system may lead to increased energy consumption and higher utility bills. If your energy bills are consistently higher than expected, it could be an indication that your system is too large for your home.

4. Excessive Humidity or Poor Indoor Air Quality: Improperly sized HVAC systems may struggle to remove moisture effectively from the air, leading to excessive humidity levels. Additionally, an oversized system may not run long enough to properly filter the air, resulting in poor indoor air quality.

While these indicators can suggest an incorrectly sized system, it's crucial to consult with an HVAC professional for an accurate assessment. They will perform a detailed load calculation, considering factors such as your home's square footage, insulation, windows, orientation, and local climate, to determine the appropriate HVAC system size for your specific needs.