A kilowatt (kW) measures how much power something draws at one moment; a kilowatt-hour (kWh) measures how much energy it uses over time. Your electric bill charges you mainly for kWh, while solar systems, generators and batteries are sized partly in kW. Knowing the difference makes your bill, a solar quote and a battery spec sheet much easier to read.
The short version: power vs energy
Think of water running from a garden hose. The kilowatt is how hard the water is flowing right now. The kilowatt-hour is how many gallons ended up in the bucket. A big flow for a short time and a small flow for a long time can fill the same bucket.
- Watt (W): a unit of power. A typical LED bulb draws under 10 watts.
- Kilowatt (kW): 1,000 watts. A central air conditioner or an electric oven element draws power measured in kilowatts.
- Kilowatt-hour (kWh): using 1 kW for one hour. It is the unit your utility meter counts and the unit you are billed for.
The math is simple: kW × hours = kWh. A 1.5 kW space heater running for 4 hours uses 6 kWh. A 10-watt LED left on for 100 hours uses 1 kWh.
Where kWh shows up on your electric bill
Whether you are on FPL (which now serves the former Gulf Power territory) or a member of a co-op such as CHELCO, Gulf Coast Electric, West Florida Electric, Escambia River Electric or Talquin, your monthly bill is built mostly around kWh. Look for these lines:
- Meter readings: the previous and current readings, and the difference between them, which is your kWh used for the billing period.
- Energy charge: your kWh multiplied by the price per kWh in your rate.
- Fuel charge: on many bills, a separate per-kWh charge that covers the utility's fuel costs.
- Customer or base charge: a fixed monthly amount you pay no matter how many kWh you use.
Because almost every variable part of the bill is a per-kWh number, cutting kWh is what lowers it. Dividing your total kWh by the number of days in the billing period gives your average daily use, which is the easiest number to compare month to month and with a solar proposal.
Where kW matters: demand and how hard your home pulls
kW describes how much power your home is pulling at any given moment. On a hot August afternoon, with the AC, pool pump, dryer and oven running together, your home's demand can be several kilowatts higher than at 3 a.m.
Most standard residential rates bill mainly on kWh, not on peak kW. Some commercial rates, and some optional rates, add a demand charge based on the highest kW you draw during the month. If your bill lists a demand charge or a kW figure, check your rate name on the bill or ask your utility how it is calculated, because spreading big loads out across the day can matter on those rates.
kW also matters for equipment sizing: a breaker, a generator, an inverter or a battery can only supply so many kilowatts at once, no matter how many kWh are available.
Estimating what an appliance costs to run
You can estimate any appliance's cost with three numbers:
- Find the wattage on its label or in the manual. If only amps are listed, multiply amps by volts (120 or 240) for an approximate wattage.
- Convert to kW (divide watts by 1,000) and multiply by the hours it actually runs per day. That gives kWh per day.
- Multiply kWh by your all-in price per kWh. To find that price, divide the total of your energy and fuel charges by the kWh billed.
Example: a 1,500-watt (1.5 kW) heater run 3 hours a night is 4.5 kWh per night, or about 135 kWh over a 30-day month. Multiply by your own per-kWh price to see the dollar figure. Remember that things with thermostats or compressors, such as refrigerators, water heaters and air conditioners, cycle on and off, so their real hours of running are lower than the hours they are plugged in. An inexpensive plug-in energy meter shows the actual kWh for 120-volt devices.
kW and kWh in a solar quote
A solar proposal uses both units, and mixing them up is the most common source of confusion:
- System size (kW): the total rated power of the panels, usually written in kW DC. A system with 24 panels rated at 400 watts each is 9.6 kW.
- Estimated production (kWh per year): how much energy the system is expected to make over a year, based on your roof direction, tilt, shading and local weather. This is the number to compare against the annual kWh on your bills.
- Price per watt: the installed price divided by the system size in watts. MSM Solar's typical pricing is about $3.25 per watt installed, so an 8 kW (8,000-watt) system would be roughly $26,000 before any site-specific changes.
When you compare quotes, compare both the price per watt and the estimated kWh per year. Two systems of the same kW can produce different kWh if one has more shade or faces a less favorable direction. Keep in mind that the 30% federal residential solar tax credit ended for systems installed after December 31, 2025, so payback math for a new home system should not include it. Florida still exempts solar equipment from sales tax and excludes the added home value from property tax assessments.
If you want a quote sized to your actual usage, our new solar installation team starts with a free site survey and your past 12 months of kWh.
Solar Cost Calculator – Florida Panhandle Only
* Estimate based on $3.25 per watt for solar installation.
* For Tesla Powerwall 3 Batteries, $15,000 for the first battery, $12,000 for each additional battery.
* Other variations and types of Batteries are available.
kW and kWh for home batteries and backup
Batteries have two ratings, and you need both:
- Capacity (kWh): how much energy is stored. Tesla lists the Powerwall 3 at 13.5 kWh of usable capacity.
- Power output (kW): how much it can deliver at once. Tesla lists the Powerwall 3 at 11.5 kW of continuous output.
Capacity decides how long you can run things during an outage; power output decides what you can run at the same time. Starting a central AC compressor, a well pump and an electric range together needs enough kW, while getting through a night needs enough kWh. A first Powerwall 3 installed by MSM Solar is typically about $15,000. The federal home battery tax credit ended along with the residential solar credit, so budget for the full installed price.
Net metering: kWh in, kWh out
With net metering, your utility meter tracks kWh in both directions: energy you take from the grid and energy your solar system sends back. FPL credits net-metered exports at the retail rate, so a kWh you export offsets a kWh you would otherwise buy. Co-ops and city utilities in the Panhandle set their own rules, which may credit exports differently, so ask your provider for its current net metering or interconnection policy before sizing a system.
On a net-metered bill you may see separate "received" and "delivered" kWh lines. The difference between them, not your total home use, is what you are billed for that month.
Simple ways to cut kWh and kW at home
- Raise the thermostat a little in summer: cooling is usually the largest kWh user in a Panhandle home.
- Run the pool pump fewer hours or at lower speed: a variable-speed pump uses far less power at low speed.
- Stagger big loads: running the dryer, oven and dishwasher at different times lowers your peak kW, which matters on demand-based rates and when sizing backup power.
- Seal ducts and add attic insulation: less heat gain means the AC runs fewer hours.
- Replace old appliances on a schedule: an older second refrigerator in a hot garage can quietly add a noticeable number of kWh each month.
Frequently asked questions
Is 1,000 kWh a month a lot for a Florida home?
It depends on the home's size, insulation, AC efficiency and whether there is a pool or electric water heating. The most useful comparison is your own home over time: look at the 12-month kWh history on your bill and compare the same months year to year.
How many kWh does a 1 kW solar system make?
It varies with roof direction, tilt, shading and weather, so any single figure is only a rough guide. A site-specific production estimate in kWh per year should be part of every solar quote you receive.
Why does my bill go up even when my kWh did not?
The price per kWh, the fuel charge or the fixed customer charge may have changed. Compare those line items, not just the total, and check that the billing period had the same number of days.
Can a battery run my whole house?
Only if its kW output covers everything you want running at once and its kWh capacity covers how long you need it. Many homes back up selected circuits or add a second battery for central AC.
Conclusion
MSM Solar works with homeowners in Seaside, St. George Island, Tallahassee, Wewahitchka, Alford, Altha and Cantonment, and in every town between Pensacola and Apalachicola.
kW is how hard your home is pulling power; kWh is how much energy it used. Your bill is mostly kWh, equipment limits are mostly kW, and a solar or battery quote needs both. Pull up your last 12 months of kWh, figure out your all-in price per kWh, and you will be able to judge any proposal with confidence. If you live in or near Crestview or anywhere else in the Panhandle, MSM Solar (Florida Certified Solar Contractor License CVC57236) offers free site surveys and written quotes. Call (850) 737-5197, and a real person will call back within 2 business days.