Key Takeaways
- Most Hampton Roads homes need a 20–22 kW generator for full coverage
- Essential circuits only? A 10–15 kW unit usually covers it
- Total installed cost ranges from $3,500 to $15,000+
- Standby generators run as long as the fuel supply lasts
- Hurricane season makes backup power a real necessity in this area
Hurricane season in Hampton Roads is not a maybe, it’s a when. If you’ve ever sat through a multi-day outage with no AC in August, you already know a whole-house generator isn’t a luxury, it’s a necessity. But figuring out what size generator for a whole house you actually need can feel overwhelming fast.
This guide breaks it down simply. The right kW for your home size, what it’ll cost, and what Hampton Roads homeowners specifically need to know before buying.
What Size Generator for the Whole House Do I Need?
Here’s the short answer:
| Home Size | Coverage Type | Recommended Size |
| Under 1,500 sq ft | Essential circuits | 10–15 kW |
| 1,500–2,500 sq ft | Whole home | 16–22 kW |
| 2,500–4,000 sq ft | Whole home | 22–27 kW |
| 4,000+ sq ft | Whole home | 30 kW+ |
These are starting points. Your actual size depends on what appliances you run and how much of your home you want powered.
How Generator Sizing Works
Generator size is measured in kilowatts (kW). You need enough kW to cover everything you want running at the same time.
Two approaches to think about:
Essential-Circuits Coverage
This means powering only what matters during an outage:
- Refrigerator
- HVAC (heating and cooling)
- Well pump (if applicable)
- Key lights and outlets
- Medical equipment
A 10–15 kW generator handles this for most homes. It’s the more budget-friendly option and covers everything you’d actually need during a storm.
Whole-Home Coverage
Want the house running like nothing happened? You’ll need 20 kW or more. This handles all lights, appliances, HVAC, and electronics at once.
Worth it if you have a larger home, a home office, or you don’t want to think about what’s on and what’s off mid-storm.
How to Calculate Your Power Needs
- List every major appliance
- Add up the continuous watts (what each uses while running)
- Factor in starting watts — motors like HVAC and fridges pull 2–3x more power when they kick on
| Appliance | Continuous Watts | Starting Watts |
| Central AC (3 ton) | 3500 | 7000 |
| Refrigerator | 700 | 2200 |
| Well pump (1 HP) | 1000 | 2100 |
| Furnace blower | 800 | 1300 |
| LED lighting | 200 | 200 |
| TV + devices | 400 | 400 |
Size your generator to handle the peak starting load, not just the running load. In the homes we service around Newport News, underestimating starting watts is the #1 sizing mistake we see homeowners make.
How Much Does a Whole-House Generator Cost?
Honest breakdown:
| Cost Component | Estimated Range |
| Generator unit | $2,000–$10,000+ |
| Automatic transfer switch | $500–$1,500 |
| Installation labor | $1,000–$3,000 |
| Permits and inspection | $100–$500 |
| Total installed | $3,500–$15,000+ |
Smaller air-cooled units (10–20 kW) sit at the lower end. Liquid-cooled units for large homes push higher. These are estimates. A professional load assessment gives you the real number for your home.
Considering a panel upgrade alongside this? Check out our electrical upgrades and installations to see what we can do.
Natural Gas vs. Propane Generators
| Feature | Natural Gas | Propane |
| Fuel supply | Utility line (no refills) | Tank (needs refilling) |
| Cost to run | Lower | Higher |
| Best for | Homes with gas service | Rural/no gas access |
| Outage risk | Low | Depends on tank level |
Most Hampton Roads homes connect to natural gas through Dominion Energy. If you have access, natural gas is usually the easier choice. No tank management, no running dry.
How Long Can a Standby Generator Run Continuously?
As long as the fuel keeps flowing.
- Natural gas: Runs indefinitely off the utility line
- Propane: A 500-gallon tank runs a 20 kW unit for roughly 6–7 days at 50% load
Most manufacturers recommend a brief shutdown every 100–200 hours for basic maintenance. Standby generators handle this automatically with scheduled exercise cycles.
Why Hampton Roads Homes Benefit From Standby Power
Real talk. If you’re in Hampton Roads, you already know how bad it can get. Hurricane season runs June through November. Coastal Virginia deals with:
- Multi-day outages after major storms
- Grid switching events from Dominion Energy
- High humidity and lightning that trips breakers and fries appliances
Homes in Newport News, Chesapeake, Virginia Beach, and surrounding areas can lose power for days after a serious storm. A standby generator kicks on within seconds of an outage. No extension cords, no flashlights, no fumbling around in the dark.
If you’re already due for an electrical safety inspection, that’s a great time to talk backup power too.
Installation, Permits & Transfer Switch
This is not a DIY project. Here’s why:
- It involves high-voltage electrical work
- It connects to a gas line
- An automatic transfer switch is required — it disconnects your home from the grid before the generator kicks in, which is critical for utility worker safety
- Permits and inspections are required in Newport News and across Hampton Roads
Skip the permit and you’ll have issues when selling the home. Your licensed electrician handles all of this.
Service Note: Generator installation as a standalone service should be confirmed with Phase 3 before publishing. In the meantime, Phase 3 can assist with transfer switch wiring, load calculations, and standby power planning as part of our electrical upgrades and installations.
When to Call a Licensed Electrician
Call Phase 3 if you’re:
- Not sure what size your home actually needs
- Adding a transfer switch to an existing portable generator
- Planning a panel upgrade alongside generator prep
- Dealing with storm-related electrical damage — our emergency electrical service is available when you need it
We’ll run through a real load calculation, explain your options, and give you a straight number, no guesswork.
Final Advice for Hampton Roads Homeowners
Getting the right size generator for a whole house comes down to one thing: knowing your actual load. Too small and your HVAC won’t run. Too big and you’re paying for capacity you’ll never use.
For most Hampton Roads homes, 20–22 kW handles the whole house and 10–15 kW covers the essentials. Both are solid options depending on your priorities and budget.
Call us at 757-THE-WIRE (757-843-9473) or book a free quote — our expert team at Phase 3 will help you figure out exactly what your home needs.
Frequently Asked Questions:
What size whole-house generator do I need?
Most homes between 1,500–2,500 sq ft need 16–22 kW for full coverage. Essential circuits only? 10–15 kW is usually enough.
How much does a whole-house generator cost?
All-in, expect $3,500–$15,000+ depending on generator size, transfer switch, and install labor.
How long can a whole-house generator run continuously?
Natural gas units run as long as the utility supply lasts. Propane depends on tank size. A 500-gallon tank gives roughly 6–7 days of runtime.
Is natural gas or propane better for a home generator?
Natural gas is easier for most Hampton Roads homeowners. Connected to Dominion Energy’s gas lines. No tank to manage, continuous fuel supply.
Do I need a transfer switch for a whole-house generator?
Yes, always. It isolates your home from the grid, protecting utility workers and your equipment.
Can a generator power my whole house?
Yes, with the right size. A 20–22 kW unit handles most homes fully. Larger homes may need 27 kW or more.
Do I need a permit to install a home generator?
Yes. Newport News and all Hampton Roads localities require permits for generator and transfer switch installation.