Knowing what you draw.
WHY IT MATTERS
Everything you buy is sized from this number, and guessing produces equipment that is too small or wastefully large.
WHAT TO LIST
Every item that uses electricity Its wattage How many hours daily it runs Whether it must run during an outage
WHERE TO FIND WATTAGE
The label on the item, or its manual.
WHAT TO DO WHEN ONLY AMPS ARE SHOWN
Multiply amps by voltage to get watts.
WHAT TO CALCULATE
- Total watts if everything ran at once: your peak load
- Total watts of essential items only: your backup load
- Units per day: watts multiplied by hours, divided by a thousand
WHY THREE NUMBERS
Each sizes a different purchase.
WHAT PEAK LOAD SIZES
A generator, or the inverter rating.
WHAT BACKUP LOAD SIZES
What you actually protect.
WHAT DAILY UNITS SIZE
Batteries and solar panels.
WHAT TO BE CAREFUL WITH
Motors and compressors, which draw far more when starting.
WHAT THAT AFFECTS
Air conditioners, refrigerators, pumps and workshop machinery.
WHAT TO ALLOW
Several times the running wattage, briefly, for those items.
WHAT HAPPENS IF YOU IGNORE IT
Equipment that trips whenever the compressor starts.
WHAT TOOL HELPS
A plug-in energy meter, for measuring rather than estimating.
WHAT TO DO WITH THE LIST
Keep it, and update it when equipment changes.
