Losses & Gains
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The performance of mechanical systems depends greatly on the capacity of the building envelope for minimizing energy loss and controlling the effects of heat gains from sunlight and occupant activity.
Heat loss may happen through almost any surface in a building - through conduction, convection or radiation.
Heat gains happen when the sun shines and heats up surfaces on a building, especially through windows. The activities of people in a building also contribute to heat gains, through cooking, bathing and breathing.
| One of the most effective approaches to retrofit work is to focus on conserving energy first - creating an energy efficient building envelope may allow for optimized and 'right-sized' mechanical equipment, with long term cost and energy savings. This places a priority on minimizing losses and unwanted gains through the envelope. |
Optimizing the building envelope to mitigate heat gains and losses may include the following:
- Increased Insulation in attics, exterior walls and basements;
- Increased Air Tightness, measuring improvements by blower door testing;
- Replacement Windows and Doors with triple glazing, low-E coatings and thermal frames. Openings must blend seamlessly into the continuous air, thermal and vapour control layers;
- Improved Moisture and Water Control with improved flashing, positive overlaps, drying potential inside and out, and the addition of rain gutters / eavestrough.