Wattage Calculator
Generator Wattage Sizing Calculator
Stop guessing. Calculate exactly what size generator or battery power station you need to survive the next LUMA blackout.
Size Your Inverter Generator for Home Emergency Backup in Puerto Rico
Surviving long-term utility grid failure, post-hurricane blackouts, and unpredictable LUMA outages requires robust home emergency backup power. Our free sizing calculator helps homeowners in San Juan, Bayamón, Ponce, Carolina, and Guaynabo find the best inverter generator for home use to keep critical loads running, including inverter air conditioners, water cistern pumps, and refrigerators.
Inverter generators produce clean, stable power (pure sine wave) to safeguard sensitive home electronics and appliances from dangerous voltage surges (bajones de luz). Order your generator online for direct shipping to Puerto Rico with no Florida freight forwarders required.
Generator Wattage Sizing Calculator
Select the appliances you plan to run at the exact same time during an outage to estimate your power needs.
⚠️ Do not select every appliance you own. Only select the items you will power simultaneously to avoid overestimating.
Start With a Preset
Select your situation and adjust from there.
Apartment
House
Refrigerator/Freezer150W / 700W
0
Inverter Refrigerator80W / 250W
0
Chest Freezer100W / 500W
0
Microwave (1000W)1000W / 1000W
0
Coffee Maker1000W / 1000W
0
Toaster850W / 850W
0
Blender400W / 850W
0
Rice Cooker700W / 700W
0
Electric Pressure Cooker1000W / 1000W
0
Air Fryer1200W / 1200W
0
Electric Griddle1500W / 1500W
0
Deep Fryer1500W / 1500W
0
Electric Oven/Range2000W / 2400W
0
Dishwasher1200W / 1500W
0
Countertop Ice Maker150W / 200W
0
Washing Machine500W / 1500W
0
Electric Clothes Dryer5400W / 5400W
0
Gas Clothes Dryer700W / 1800W
0
Clothes Iron1200W / 1200W
0
Electric Water Heater4500W / 4500W
0
Electric Showerhead Heater (Ducha)3500W / 3500W
0
Cistern Pump (1/2 HP)800W / 2000W
0
Cistern/Tank Pump (3/4 HP)1200W / 3000W
0
Pressure Booster Pump500W / 1500W
0
Well Pump (1/2 HP)1000W / 3000W
0
Sump Pump (1/2 HP)800W / 2100W
0
Ceiling Fan75W / 120W
0
Pedestal/Standing Fan75W / 75W
0
Box Fan100W / 100W
0
Inverter AC (9k BTU)700W / 1000W
0
Inverter AC (12k BTU)1000W / 1500W
0
Inverter AC (18k BTU)1500W / 2000W
0
Inverter AC (24k BTU)2200W / 2800W
0
Window AC (10k BTU)1200W / 3600W
0
Window AC (15k BTU)1800W / 5400W
0
Central AC (2 Ton)2800W / 8400W
0
Central AC (3 Ton)4500W / 13500W
0
Dehumidifier300W / 300W
0
Humidifier200W / 200W
0
LED/LCD TV80W / 80W
0
Cable/Satellite TV Box30W / 30W
0
Gaming Console200W / 200W
0
Modem/Router20W / 20W
0
Starlink Dish65W / 65W
0
Security Camera System (NVR)50W / 50W
0
Laptop Computer50W / 50W
0
Desktop Computer300W / 300W
0
Laser Printer600W / 600W
0
Inkjet Printer30W / 30W
0
Smartphone Charger10W / 10W
0
Tablet Charger20W / 20W
0
LED Bulb (x1)10W / 10W
0
CPAP Machine (no humidifier)50W / 50W
0
CPAP Machine (with humidifier)100W / 100W
0
Oxygen Concentrator300W / 300W
0
Baby Monitor5W / 5W
0
Pool Pump (1 HP)1500W / 3600W
0
Outdoor Water Pump (1/2 HP)800W / 2000W
0
Electric BBQ Grill1500W / 1500W
0
Outdoor String Lights (LED)50W / 50W
0
Mosquito Trap / Bug Zapper40W / 40W
0
Corded Drill600W / 900W
0
Circular Saw1400W / 2300W
0
Table Saw1800W / 4500W
0
Air Compressor (1 HP)1500W / 4500W
0
Shop Vac1000W / 1500W
0
Bench Grinder1400W / 2500W
0
Belt Sander1200W / 2400W
0
RV AC (13.5k BTU)1500W / 3500W
0
RV Refrigerator200W / 200W
0
Hair Dryer1800W / 1800W
0
AM/FM Radio50W / 50W
0
Total Running Watts:
0 W
+
Total Starting Watts:
0 W
(Includes highest starting wattage)
Frequently Asked Questions
Yes, but inverter generator sizing is critical. According to Innovair HVAC and EcoFlow's generator sizing guide, a 12,000 BTU mini-split typically requires 2,000–2,500 running watts, while an 18,000 BTU unit needs 3,000–3,500 running watts. Keep in mind that starting wattage (surge) is generally double the running wattage — so always size your generator to handle that initial surge. A 5,000W+ inverter generator is recommended for reliable mini-split operation, especially when powering other home appliances simultaneously during LUMA power outages. Source: Innovair HVAC (innovair.com) | EcoFlow Generator Sizing Guide (ecoflow.com)
Yes, but you must use a generator or battery backup system with pure sine wave output. According to Jackery and the PoweredThrough Medical Device Guide, CPAP machines consume 30–60 watts without a humidifier, rising to 70–100 watts with a heated humidifier. Pure sine wave output is essential — modified sine wave power can cause erratic device behavior or damage sensitive medical electronics. For overnight CPAP use (8 hours), a battery power station with at least 600–800Wh capacity is recommended. An oxygen concentrator draws significantly more — 100–300 watts — and requires a minimum of 2,000Wh capacity for extended use. Source: Jackery CPAP Power Guide (jackery.com) | PoweredThrough Medical Device Guide (poweredthrough.com)
Running watts (also called rated watts) are the continuous power an appliance needs to operate normally. Starting watts (also called surge watts) provide a brief 2–3 second burst of extra power needed to start motor-driven appliances like refrigerators, air conditioners, and pumps. When sizing a generator, you must account for both — your generator needs to handle the starting watts of the largest motor in your setup, plus the combined running watts of everything else.
Add up the running watts of all the appliances you plan to run at the same time. Then add the single highest starting wattage from that list. This total is your minimum required generator starting wattage. Use the wattage calculator above to do this automatically — select only the appliances you will run simultaneously, not every appliance you own.
If your generator is undersized, it will overload and shut down — and can potentially damage both the generator and your connected appliances. Generator sizing experts recommend always targeting at least 20% more wattage than your estimated total (a 20% safety margin) to safely accommodate startup surges and load fluctuations. To protect sensitive electronics from voltage fluctuations and "bajones de luz" when the grid fluctuates, use a high-quality inverter generator which outputs a clean pure sine wave. Source: Fahrenheit AC (fahrenheitacfl.com)
It depends on your home size and the generator's capacity. Small to medium portable generators (3,000–8,000W) are best suited for essential circuits. To power an entire home including central AC and major appliances, you typically need a standby generator or a very large portable unit (10,000W+). For most Puerto Rico homes, focusing on essential circuits — refrigerator, AC unit, lights, fans, and communications — is the most practical and cost-effective approach during an outage.