Self-Consumption Rate
The percentage of your solar generation that you actually use — rather than sending back to the grid. In states without net metering, it's the single most important variable in your payback calculation.
The definition
Self-consumption rate = the percentage of your solar system's output that you consume directly in your home, rather than exporting to the grid.
Self-consumption rate = 600 ÷ 1,000 × 100 = 60%
In plug-in solar states like Utah and Maine, exported power is not credited (no net metering). Those 400 exported kWh are effectively donated to the grid for free. At $0.14/kWh, that's $56/year in lost savings — every year.
Why it matters more for plug-in solar
Rooftop solar owners in most states can sell excess power back to the grid at the retail rate through net metering. Every kWh generated is worth something regardless of when it's used.
Plug-in solar is different. Utah's HB 340 and Maine's LD 1368 — the two laws that legalized plug-in solar in the US — both explicitly exclude these systems from net metering. Exported power has zero value. This makes self-consumption the mechanism through which your system generates savings.
Impact of self-consumption rate on a 800W system at $0.17/kWh
| Self-consumption | kWh used/yr | Annual savings | 10-year savings | Payback (on $1,200) |
|---|---|---|---|---|
| 30% | 370 | $63/yr | $630 | 19 yrs |
| 45% | 554 | $94/yr | $940 | 13 yrs |
| 60%(calculator default) | 739 | $126/yr | $1,260 | 10 yrs |
| 75% | 924 | $157/yr | $1,570 | 8 yrs |
| 90% | 1,109 | $188/yr | $1,880 | 6 yrs |
Typical rates by household type
Self-consumption is primarily determined by when you use electricity. Solar generates from roughly 8am to 5pm, with a peak around noon. The more of your consumption falls in that window, the higher your rate.
Most generation occurs while the home is empty. Only base loads (fridge, standby) consume solar. Most kWh are exported or lost.
Some daytime activity — morning routines, occasional use. About half of generation is used; the rest lost to the grid.
Home office, retired, or part-time schedule. Cooking, appliances, climate control occur during solar hours. Good baseline self-consumption.
Deliberate appliance scheduling during solar hours. Laundry at noon, pre-cooling, EV charging. No battery needed to achieve strong results.
Battery stores excess midday generation for evening peak consumption. Best-case scenario — most of what's generated is used, even in empty households.
What affects your self-consumption rate
Occupancy hours
The single biggest factor. If your home is empty 9–5, your consumption pattern is almost entirely out of phase with solar generation. Even partial daytime presence dramatically improves the rate.
System size vs. household load
Oversizing your system relative to your daytime load creates surplus you can't consume. A 600W system in a home that draws 200W during the day will have 400W of unavoidable excess.
Battery storage
A battery decouples generation from consumption by storing midday surplus and releasing it during the evening peak. The most impactful upgrade for households with low daytime occupancy.
Appliance scheduling
High-draw appliances (dishwasher, washer, oven) can be deliberately scheduled to run during peak solar hours. Smart plugs and timer outlets make this automatic.
Climate control
HVAC is the largest residential load. Pre-cooling or pre-heating during peak solar hours shifts significant load into the generation window and reduces evening grid demand.
Season and sun hours
In summer, longer solar windows mean more overlap with typical household activity. In winter, the generation window narrows and peaks when most people are still at work.
10 ways to improve your self-consumption rate
Roughly ordered by impact. The free behavioral changes alone can push a typical household from 45% to 65%.
Run your dishwasher at noon
HighCost: FreeA dishwasher draws 1,200–1,800W. Running it during peak solar hours (10am–2pm) can consume most of what a 600–800W system generates in a single cycle. Set a delayed-start timer the night before.
Do laundry during solar hours
HighCost: FreeWashing machines use 500W on the cycle and up to 5,000W on heat-dry. Running a full load during peak generation hours is one of the highest-impact free changes you can make.
Pre-cool or pre-heat your home
Very highCost: FreeHVAC is typically the largest load in any home. Running it harder during solar hours — cooling your home to 68°F at noon rather than 72°F — uses solar power and requires less energy at night.
Charge devices and EVs during the day
Medium–HighCost: FreePhone and laptop charging is negligible, but EV charging is significant (Level 1 = 1,440W, Level 2 = 7,200W+). Even Level 1 charging during peak solar hours absorbs most of a 600–800W system's output and can meaningfully raise your self-consumption rate.
Use smart plugs to automate appliances
MediumCost: $15–40 per plugSmart plugs with scheduling let you automatically turn on high-draw appliances during solar hours without thinking about it. Pair with a solar monitoring app to automate based on actual generation, not just time of day.
Add a battery buffer kit
Very highCost: $500–1,200 for the batteryA battery stores excess midday generation and releases it during the evening peak (5–10pm), when your household typically uses the most electricity but solar has stopped. A 1–2kWh LFP battery typically raises self-consumption from 45–55% to 75–90%.
Right-size your system
HighCost: Free (planning decision)A 1,200W system in a 500 sq ft apartment with one resident will have poor self-consumption — it generates more than the apartment uses during the day. Matching system size to your actual daytime load is more efficient than going maximum size.
Work from home
HighCost: FreeOffice workers who leave at 8am and return at 6pm lose most of their solar generation to the grid (in states with net metering) or lose it entirely (in states without). Working from home — even two days a week — meaningfully shifts consumption into solar hours.
Use a monitoring app with real-time alerts
MediumCost: Usually included with systemMany plug-in solar systems include apps that show live generation in watts. Setting a notification at "system generating above 400W" prompts you to run a load during peak generation — turning passive savings into active optimization.
Cook during solar hours
MediumCost: FreeElectric stovetops and ovens draw 1,000–3,000W. Cooking lunch or batch-cooking dinner ingredients during peak solar hours shifts significant load into your generation window. Slow cookers (200–300W running) are especially good as they run for hours during the day.
Frequently asked questions
What is the default 60% used in the calculator?
Does self-consumption matter if my state has net metering?
Can I measure my actual self-consumption rate?
Is higher self-consumption always better?
Why is self-consumption so much more important for plug-in solar than rooftop solar?
Does battery storage really make that big a difference?
See how self-consumption affects your numbers
The payback calculator lets you adjust your self-consumption rate with a slider. Move it from 40% to 80% and watch how dramatically the payback period changes.