Generator sizing Updated June 2026
Portable vs Standby Generator: Which Size Do You Need?
By Yann Buf, HVAC tech 5 min read Standards-reviewed
Choose a portable generator (3,500-7,500W) for occasional outages and a budget under $1,500. Choose a standby generator (14,000-22,000W) for automatic backup, whole-home coverage, and if you have medical needs or frequent outages.
Portable vs Standby: The Key Difference
The fundamental difference is not just size — it's how the generator connects to your home. A portable generator sits outside, requires manual setup during an outage, and connects via extension cords or a manual transfer switch. A standby generator is permanently installed, connected to your home's electrical panel, and turns on automatically within seconds of a power outage.
Portable generators are typically 3,500-7,500W and cost $400-1,500. Standby generators start at 7,500W (rare) and go up to 22,000W+, costing $2,000-6,000 plus installation ($1,000-2,500). The standby generator's value is convenience and automation — you don't have to go outside in a storm to start it.
For sizing: a portable generator powers select circuits (fridge, furnace, lights, well pump). A standby generator powers your entire home including central AC, electric stove, and dryer.
Top picks for this size
No specific product recommendations for this size yet. Try the calculator for tailored picks.
Which Generator Type Is Right for You?
- Choose portable (3,500-7,500W, $400-1,200) if: outages are rare (1-2 per year), budget is under $1,500, you have a manual transfer switch or extension cords, you want a generator you can take camping or to job sites
- Choose standby (14,000-22,000W, $3,000-6,000) if: outages are frequent or long (3+ days), you have medical equipment that can't lose power, you want automatic reassurance, you have a propane or natural gas line
- Consider a hybrid approach: a portable 3,500W now for essential circuits, upgrade to standby later if needed
Frequently asked questions
Can I install a standby generator myself?
No. Standby generator installation requires a licensed electrician for the automatic transfer switch and electrical connections, and often a plumber/technician for gas line installation. Total installation cost is typically $1,500-3,000.
Do standby generators require maintenance?
Yes. Standby generators have automatic weekly self-tests (about 15 minutes), but still need annual maintenance including oil changes, spark plug replacement, and battery checks. Plan for $200-400/year in maintenance costs.
What's the lifespan of a portable vs standby generator?
A well-maintained portable generator lasts 2,000-3,000 hours of use (10-15 years for typical home backup). A standby generator lasts 15-25 years with proper maintenance. Standby generators also have better resale value if you move.