Modeling Multifamily Heating Energy Use

1. Modeling Multifamily Heating Energy Use Can SEEM be used, or do we need to use a multi-zone model? Regional Technical Forum January 17, 2011

2. Background • MF Weatherization UES is “out-of-compliance” due to lack of model calibration • In the RTF’s “Multifamily Weatherization UES Scoping Study (Phase 1),” SBW identified 5 studies that would provide useful data for calibration • See link to memo on MF Weatherization UES measure page • In “Phase 2,” the RTF will hire a contractor to use those 5 studies to perform a calibration exercise. • The SOW should specify the preferred model. • RTF-staff preference = SEEM • At the December 2011 RTF meeting, there was concern regarding using SEEM for multifamily buildings

3. Today • What’s Needed from RTF… • Clear direction regarding modeling software and approach to use for the Multifamily Weatherization UES measures and attempted calibration exercise.

4. Background (2) • Definition: Multifamily • More than 4 units; and • 3 floors or less above grade • Prototypes • Townhouse • 12 units • 3 stories • 1500 ft2 per unit • Apartment Building (Double-loaded corridor) • 24 units • 3 stories • 1000 ft2 per unit • Apartment Building (Outdoor Entry) • 8 units (4 units per floor) • 2 stories • 942 ft2 per unit • Measures • Insulation (Attic, Floor, Walls) • Windows

5. Use SEEM or not? • Benefits of using SEEM • Consistent with other RTF work • Simple • Easily documentable • Negatives of using SEEM • Doesn’t allow for multi-zone modeling

6. Discussion • What would we expect to get from multi-zone modeling that single-zone modeling wouldn’t provide? • Will ability to model common areas and individual dwelling units allow better savings estimates? • Common area heating setpoint & ventilation rates • Vary heating setpoint across units to account for different behavior (including vacancies) • What data would we need for model inputs?

7. Option 1Buildings with common areas are too different – leave them out • Assumption • Since measures are typically performed on the whole building, interaction between apartments and their different t-stat settings average out. • Model Using SEEM • Prototypes • Use the Townhouse and Outdoor Entry Apartment Prototypes modeled with both slab and crawlspace, weighted appropriately • Do not model the double-loaded corridor prototype • Calibration Data • Only include data from exterior entry buildings without significant common areas • Measures • Disallow buildings with interior entries and common areas

8. Option 2Buildings with common areas are different, but savings will be similar • Assumption • Savings from improved insulation and windows will be similar for all buildings, even with the HVAC/ventilation impact on buildings with common areas • Model Using SEEM • Prototypes • Use the Townhouse and Outdoor Entry Apartment Prototypes modeled with both slab and crawlspace, weighted appropriately • Do not model the double-loaded corridor prototype • Calibration Data • Where possible, only include data from interior entry buildings with common areas where there are adequate data available for the common areas to allow their removal from the SEEM modeling • Measures • Continue allowing buildings with interior entries and common areas as long as they meet the MF definition (i.e. 3 stories or less, more than 4 units)

9. Other options…Yes • Discussion • Direction (or Decision, if necessary)