Short Answer: Weather can vary significantly from one year to the next so developing
“typical “meter-based weather sensitive load profiles would require 8760 load data for
many years, which does not exist. Space heating, AC and ventilation electricity use is
determined primarily by outdoor weather temperatures and does not reflect the random
load patterns of non-weather sensitive loads. Fortunately, many years of weather data
are available to develop typical weather profiles for more than 900 locations across the US.
These weather data are applied to develop MAISY RECS weather-sensitive hourly loads.
Longer Answer: MAISY RECS Residential Hourly Load Databases apply EPlus
engineering analysis to calculate space heating, air conditioning and ventilation loads (weather
sensitive loads or WS loads). EPLUS is a US Department of Energy engineering heat load model that
calculates hourly kW use for space heating, air conditioning and distribution based on dwelling
unit, occupant characteristics and weather data.
EPLus model simulations from more than 900 weather stations are used to develop
weather-sensitive hourly load estimates for “typical meteorological year (TMY)” data.
TMY data reflect typical hourly data for actual days in individual months based on
an analysis of historical data. This database reflects typical hour to hour variation
in outdoor temperatures. This approach is superior to modeling WS loads based on average
daily temperatures as averages dampen hour to hour variations that are important in
estimating peak kW impacts of weather. Simulation results are calibrated to individual
RECS record space heat, air conditioning, and ventilation (fans and pumps) annual kWh
estimates and dwelling unit floor space.