Whole House Generator Cost 2025: Standby Installation Prices & Sizing Guide
Power outages are no longer just an inconvenience; they are a threat to your home's safety and comfort. Whether it’s a winter storm in Texas or a hurricane in Florida, losing power means no heat, no air conditioning, and spoiling food. How much does a whole house generator cost in 2025?
The national average cost to install a standby generator ranges from $5,000 to $12,500. While a small portable unit might cost $800, a permanent whole-home system (14kW - 22kW) that kicks on automatically requires a significant investment in equipment, electrical work, and plumbing.
In this guide, we break down the costs of Standby vs. Portable generators, fuel types (Propane vs. Natural Gas), and the hidden installation fees nobody tells you about.
⚠️ Electrical Warning
Installing a generator involves connecting high-voltage electricity to your main service panel. Improper installation can cause "backfeeding," which can electrocute utility workers fixing power lines down the street. Always hire a licensed electrician. (See our Electrical Panel Upgrade Guide).
1. Standby vs. Portable: What's the Difference?
The price gap is huge, but so is the convenience.
Portable Generators ($500 - $2,000)
Best for: Essentials only (Fridge, a few lights, phone chargers).
Pros: Cheap, mobile.
Cons: You must drag it outside in the rain, fill it with gas manually, and run extension cords everywhere. No automation.
Whole House Standby Generators ($5,000 - $15,000+)
Best for: Powering the entire home (AC, Heater, Sump Pump).
Pros: Turns on automatically within 10 seconds of an outage. Runs on your home's natural gas or propane supply (no refueling).
Cons: Expensive installation. Requires permits and a concrete pad.
2. Cost Breakdown by Size (kW)
Generator size is measured in kilowatts (kW). To run a central air conditioner (See HVAC Costs), you typically need at least 14kW.
| Size (kW) | Unit Price | What It Powers |
|---|---|---|
| 7kW - 10kW | $2,000 - $3,500 | Lights, Fridge, Sump Pump (No AC). |
| 13kW - 18kW | $3,500 - $5,000 | Small AC (3-ton), most appliances. |
| 20kW - 26kW | $5,000 - $7,000 | Whole house luxury (Large AC, Electric Oven). |
3. Installation Labor Costs
Buying the unit is only half the cost. Installation is complex and typically costs between $3,000 and $6,000 alone.
- Electrician ($80 - $120/hr): Must install an Automatic Transfer Switch (ATS). This device senses power loss and switches the house to generator power.
- Plumber ($90 - $150/hr): Must run a gas line from your meter to the generator. If you don't have natural gas, you'll need a large propane tank installed.
- Site Prep: The generator needs a poured concrete pad or a leveled gravel bed ($300 - $600).
4. Operating Costs and Maintenance
Like a car, a generator has an engine that needs oil changes and filters.
- Annual Maintenance Contract: $200 - $400 per year.
- Fuel Consumption: A 20kW unit can consume 2-3 gallons of propane per hour. A 3-day outage could cost $300+ in fuel.
5. Does a Generator Increase Home Value?
Yes. Remodeling Magazine reports that a standby generator offers a 50% to 70% ROI (Return on Investment). In storm-prone areas, it is a major selling point that sets your home apart.
Conclusion
A whole house generator is an expensive insurance policy, but for families with medical needs or those working from home, it is priceless. The peace of mind knowing your lights will stay on when the grid fails is worth the investment.
Need to upgrade your panel to handle the new generator? Read our guide on Electrical Panel Replacement Costs.
Disclaimer: Costs are national averages for 2025. Brands like Generac, Kohler, and Briggs & Stratton vary in price. Always check local noise ordinances before installation.