Draw pattern
A draw pattern is the standardized daily hot-water usage profile (Very Small, Low, Medium, or High) a water heater is tested under for its UEF rating. It indicates the household size the unit is designed to serve.
The DOE test procedure assigns each model one of four patterns based on its capacity — from Very Small (about 10 gallons per day, point-of-use units) to High (around 84 gallons per day, large-family units). The UEF number is only comparable between models tested on the same pattern.
For buyers, the pattern is a quick size class: a High-usage-rated unit is engineered for the demand of a large household, while a Low-usage unit will run efficiently in a small one.