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

Background MF Weatherization UES is out-of-compliance due to lack of model calibration In the RTFs 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 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 2

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

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

Use SEEM or not? 5 Benefits of using SEEM – Consistent with other RTF work – Simple – Easily documentable Negatives of using SEEM – Doesnt allow for multi-zone modeling

Discussion What would we expect to get from multi-zone modeling that single-zone modeling wouldnt 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? 6

Option 1 Buildings 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 7

Option 2 Buildings 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) 8

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