Key takeaways
- An 800 W kit rarely produces 800 W — expect a midday peak of roughly 550–700 W in good sun.
- In a typical US location it makes about 2.5–4 kWh on a sunny day and roughly 3 kWh a day averaged over the year.
- That covers a refrigerator, router, TV and laptops during daylight — but not an air conditioner or electric oven on its own.
- Plug-in solar doesn't power specific devices: it offsets whatever your home is using while the sun shines.
- Over a year, an 800 W kit typically offsets 900–1,400 kWh — roughly 9–13% of an average US home's use.
"800 watts" sounds like it should run a microwave. It won't — and that's not how plug-in solar works anyway. Here's what an 800 W balcony kit really produces, and what that means for your home.
800 W on the box ≠ 800 W from the outlet
The 800 W rating usually refers to the panels' combined capacity under laboratory test conditions (or the microinverter's maximum output). Real life is messier:
- Panels heat up in the sun and lose a few percent of output.
- Inverter, wiring and dust losses take another slice.
- Panels are rarely perfectly aimed at the sun.
On a clear day around noon, a well-placed 800 W kit typically delivers 550–700 W. Mornings, evenings, clouds and winter bring that down considerably.
How much energy per day?
Energy (what you pay for) is power × time, measured in kilowatt-hours (kWh).
| Conditions | Typical daily output (800 W kit) |
|---|---|
| Clear summer day, south-facing, tilted | 3.5–4.5 kWh |
| Clear spring/fall day | 2.5–3.5 kWh |
| Clear winter day | 1.5–2.5 kWh |
| Overcast day | 0.5–1.5 kWh |
| Year-round average (typical US site) | ≈ 3 kWh/day |
A vertical railing mount produces roughly 30% less over a year; an east- or west-facing one about 18% less. See best direction and angle.
Over a year, that's roughly 900–1,400 kWh. The average US home uses about 10,500 kWh a year, so an 800 W kit offsets around 9–13% — more in a small apartment.
It doesn't "run" appliances — it offsets them
A plug-in system isn't wired to any particular device. It feeds power into your home's circuits, and whatever is drawing power at that moment uses solar first. Think of it as shrinking your daytime baseline.
So the useful question is: how much of my daytime use can it cover?
Typical appliance draws
| Device | Typical draw while running | Daily energy |
|---|---|---|
| Wi-Fi router + modem | 10–20 W | 0.25–0.5 kWh |
| Refrigerator (modern) | 30–60 W average* | 1–1.5 kWh |
| Chest freezer | 20–40 W average* | 0.5–1 kWh |
| Laptop | 30–70 W | 0.2–0.5 kWh |
| TV (LED, 50") | 60–120 W | 0.3–0.6 kWh |
| Desktop PC + monitor | 100–300 W | 0.5–2 kWh |
| Ceiling fan | 15–75 W | 0.1–0.6 kWh |
| Window AC | 500–1,500 W | varies widely |
| Space heater | 750–1,500 W | varies widely |
| Microwave | 1,000–1,500 W | short bursts |
| Electric oven | 2,000–5,000 W | short bursts |
*Fridges and freezers cycle on and off; the figure is the average over a day.
What 800 W covers well
- Always-on loads: fridge, freezer, router, standby electronics, ventilation — typically 100–300 W in an apartment, 200–500 W in a house. An 800 W kit can cover these almost completely while the sun is up.
- Home office: laptops, monitors, lights and chargers.
- Daytime entertainment: TVs, game consoles, speakers.
What it only partly covers
- Air conditioning on a sunny afternoon — a useful offset, but not the whole draw.
- Laundry, dishwasher, cooking — big bursts of power. Running them around midday captures more solar.
Why 800 W is the sweet spot
Plug-in systems aren't net-metered, so surplus exported to the grid earns nothing. A home with a 250 W daytime baseline will export part of a midday 650 W peak. That's why:
- 800 W suits most apartments and typical households;
- 1,200 W makes sense for larger homes, work-from-home households or with a battery;
- shifting loads (laundry, dishwasher, charging) to midday raises the value of every watt.
More on this in how much balcony solar saves and plug-in solar with a battery.
What it's worth in dollars
At the US average of about 18¢/kWh, an 800 W kit using 80% of its output at home saves roughly $165 a year. In California it's about $378, in Massachusetts about $251. See every state in our ranking, or run your own numbers in the calculator.
Frequently asked questions
Can an 800 W solar kit run a refrigerator?
During daylight, yes in practice: a modern refrigerator averages around 30–60 W of continuous draw (about 1–1.5 kWh a day), well within what an 800 W kit produces in decent sun. At night the fridge runs on grid power unless you add a battery.
How many kWh does an 800 W solar system produce per day?
Roughly 2.5–4 kWh on a clear day in most of the US with good placement, and around 3 kWh a day averaged over a year. Winter days and vertical railing mounts produce less.
Can 800 watts of solar run an air conditioner?
It can offset part of one. A window AC draws roughly 500–1,500 W when the compressor runs. On a sunny afternoon an 800 W kit might supply a large share of a small unit's draw, with the grid covering the rest.
What percentage of my electric bill will 800 W of solar cover?
For an average US home using about 10,500 kWh a year, an 800 W kit offsets roughly 9–13%. For a small apartment using 4,000–5,000 kWh, it can be 20% or more.