7.1.7 Describe the effect of mechanical systems on heat, air and moisture movement in the building

  • Heating Systems:
    • Boilers add heat but allow air to circulate freely, while furnaces add heat and mechanically move air within the building.
    • Some boilers and furnaces also draw combustion air from the building. Water heaters usually draw combustion air from the building.
  • Ventilation:
    • Exhaust fans move local air and moisture out of the building;
    • HRVs do the same while transferring heat to incoming air.
    • ERVs bring in fresh air with little change in temperature or humidity.
  • Air Conditioning:
    • Cools and dries air while circulating it within the house.
    • Residential system usually do not exchange air with the outside