Every generator and power station listing shouts a wattage number at you — 2,000W, 3,600W, 4,000W — but that number is meaningless until you know what you actually need to run. Buy too small and your fridge trips the unit mid-outage. Buy too big and you've overpaid for capacity you'll never use.
This guide breaks down real wattage draw by room, so you can build your own list before you shop. If you'd rather skip the math, our calculator does this automatically based on your specific home — but it helps to understand what's going on under the hood either way.
Running Watts vs. Surge Watts — The One Thing That Trips Everyone Up
Every appliance has two numbers that matter:
- Running (or rated) watts — what it draws once it's up and running, steady-state.
- Surge (or starting) watts — the brief spike when a motor or compressor first kicks on, typically 2–4x the running wattage. This lasts a second or two, but your generator or power station has to be able to handle it, or the appliance won't start at all.
A refrigerator rated at 700 running watts might briefly spike to 2,000+ watts the instant its compressor kicks on. This is the single most common sizing mistake — adding up only running watts and ending up with a unit that can't actually start your fridge.
Kitchen
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| Refrigerator/Freezer | 500–700 | 2,000–3,000 |
| Microwave (compact) | 600–900 | — |
| Microwave (full-size) | 1,000–1,200 | — |
| Coffee Maker | 800–1,500 | — |
| Electric Range (1 burner) | 1,500 | — |
| Dishwasher | 1,200–1,500 | 1,800 |
The fridge is almost always the single most important appliance to plan around during an outage — it's the one thing running continuously, 24/7, whether you're paying attention or not.
Laundry
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| Washing Machine | 1,200 | 2,300 |
| Electric Dryer | 3,000–5,000 | — |
| Gas Dryer (electric ignition/controls only) | 300–500 | — |
Electric dryers are one of the biggest single loads in a home — genuinely worth skipping during a short outage rather than sizing your whole system around it. If you have a gas dryer, it draws far less since it's only powering the controls and ignition, not generating heat electrically.
Family Room / Home Office
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| TV | 100–300 | — |
| Wifi Router/Modem | 15–30 | — |
| Laptop | 60–100 | — |
| Desktop Computer | 200–300 | — |
| Phone Charger | 5–15 | — |
This category is cheap to cover — a small power station handles all of it with room to spare, which is exactly why even a budget-tier battery is worth having on hand even if you're mainly relying on a generator for the big stuff.
Bedroom / Medical Equipment
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| CPAP Machine | 30–60 | — |
| Box Fan | 100 | — |
| Electric Blanket | 200–400 | — |
| Window AC Unit | 900–1,440 | 2,200–4,800 |
If anyone in your household relies on medical equipment, size around that first — it's non-negotiable, and it's also low-wattage enough that even a small backup battery reliably covers it for days.
Basement / Utility
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| Sump Pump (1/3 HP) | 800–1,050 | 2,000–3,000 |
| Well Pump (1/2 HP) | 1,000 | 3,000 |
| Furnace Fan (1/2 HP) | 875 | 2,300 |
If you're in a flood-prone area, the sump pump is arguably as important as the fridge — a pump that stops running during the exact storm that knocked out your power is how basements flood.
Heating & Cooling (The Big Loads)
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| Space Heater | 1,500–1,800 | — |
| Central AC (10,000 BTU) | 1,500 | 6,000 |
| Central AC (24,000 BTU) | 3,800 | 15,000 |
| Heat Pump | 4,700 | 12,000 |
This is where the math changes everything. Central air conditioning alone can exceed what most portable power stations are rated for — this is usually the deciding factor between "a battery covers everything I need" and "I actually need a generator." If central AC is non-negotiable for you (extended heat, a medical need for climate control), that alone often settles the generator-vs-battery decision covered in our full comparison guide.
Putting It Together: A Worked Example
Say you want to cover: fridge (700W), wifi router (25W), a few lights (150W total), phone charging (15W), and a sump pump (1,050W running / 3,000W surge).
Running watts total: 700 + 25 + 150 + 15 + 1,050 = 1,940W Surge watts to plan for: the sump pump's 3,000W surge happens on top of everything else already running, so you need headroom above 1,940W to absorb that spike — roughly 3,000–3,500W of surge capacity to be safe.
That's a realistic profile for a mid-capacity power station or a mid-size portable generator — not the biggest unit on the market, but more than the smallest.
Skip the Math
Manually adding up your own household's appliances works, but it's easy to miss something (or double-count). The faster, more accurate way:
Use our free Generator & Home Battery Calculator →
Answer a few questions about your home and your must-keep-running list, and it'll size a system for you — running watts, surge watts, and specific product recommendations included.
Related reading: Generator vs. Home Battery: Which Backup Power Is Right for You? and Best Portable Power Stations & Home Batteries of 2026