It is important to consider what clients are asking to accomplish when embarking on a deep energy retrofit in order to predict energy savings in buildings. In general, whole building retrofits are done approximately every 50 years. Clients usually have multiple goals for retrofits...I have never had a client ask me to give them just the same space that they have now, only retrofitted to current codes. Owners want to update their buildings, but they also want to improve their function as well. Maybe this means adding a community room with a kitchen, improving the lighting, adding an elevator, adding automatic entrance doors, adding air-conditioning, or computer rooms, or dishwashers, or garbage disposals, or laundry facilities, or adding TV and data ports to each unit. In addition, the code may require fresh-air systems, upgraded electrical service entrances, and life safety systems that all require more energy.
At MDH there were no cooking facilities onsite so the client wanted a microwave and mini-fridge in each unit as well as a place to prepare hot food and clean up on each floor. Through interviews with the residents we learned that the gang bathrooms were really only used by one resident at a time. We believe that by providing single-user restrooms as well as showers in the cold-weather shelter that we have increased the use of showering, and, subsequently, hot-water.
Some building owners want to add space in the form of additions or making a more efficient use of space that exists. Perhaps the owner wants to implement changes that have the potential to lower energy consumption as well. For example, reducing the unit count of studios and converting to one-bedrooms or combining units to lower density are ways that energy might be reduced. But typically the desires for the new building increase the energy consumption for the new project. Making these changes part of the discussion and the prediction for the future energy profile of the building are important as the increase in energy consumption can be significant.