What is self-consumption in a balcony solar calculation?

Self-consumption is the percentage of generated electricity used in the home while it is available. This calculator values onsite use and assigns no value to exported energy.

Does this calculator determine whether a solar system is legal?

No. It estimates energy and savings only. It does not verify local law, utility rules, certification, safe mounting or electrical suitability.

Free planning calculator

Balcony solar savings calculator

Q: How much electricity does an 800W balcony solar system produce?

Using 4.5 good sun hours per day and an 82 percent performance factor, an 800W system produces an estimated 1,077 kWh per year before accounting for self-consumption.

Estimate annual production, monthly bill savings and simple payback. The result is a planning range—not a performance promise.

Built by Johnny AltoCalculator version 1.0Updated October 25, 2026

Your system

Use the system’s AC output when available. Adjust each input to match your actual plan.

System size (watts AC) Good sun hours per day Electricity price ($/kWh) Total system cost ($) Self-consumption (%)

The model applies an 82% performance factor for heat, conversion, orientation and other losses. It assigns $0 to exported electricity unless you change your estimate externally.

Your planning estimate

Estimated bill reduction$0/mo

Energy generated—

Energy used onsite—

Savings per year—

Simple payback—

Performance factor82%

Value assumption—

Actual results vary with shade, angle, weather, downtime, load timing, utility rules and product performance. This calculator does not determine legality, certification or electrical suitability.

Transparent method

How the calculation works

Annual production = AC system size in kW × daily good-sun hours × 365 × 0.82.

Onsite energy = annual production × self-consumption percentage.

Annual savings = onsite energy × electricity price.

Simple payback = total system cost ÷ annual savings.

This is intentionally conservative about exports: it assigns no value to electricity you do not use onsite. If your utility has a verified export-payment program, model that value separately.

How to choose the inputs

System size: enter maximum AC output, not only the sum of panel nameplate watts.
Good sun hours: use an annual average for the actual orientation and shade, not the longest summer day.
Electricity rate: use your marginal per-kWh price from a recent bill.
Total cost: include the complete system, compatible mounting and any required installation work.
Self-consumption: estimate how much energy you can use while the system is producing.

California reader? Savings do not establish legality. California’s new SB 868 utility-interconnection exemption starts January 1, 2027 and applies only to complete systems meeting every statutory condition. Read the sourced California guide.

Quick answers

Balcony solar savings FAQ

How much electricity does an 800W balcony solar system produce?

With 4.5 good sun hours per day and the calculator’s 82% performance factor, the estimate is about 1,077 kWh per year before self-consumption.

What is self-consumption?

It is the share of generated electricity used in your home while it is available. Higher self-consumption usually creates more bill value when exported electricity receives little or no credit.

Is this a quote or guarantee?

No. It is a planning model. Real output and savings depend on hardware, orientation, shade, weather, downtime, rates and when you use electricity.

Does the calculator tell me whether a system is legal?

No. It does not verify laws, utility requirements, complete-system certification, safe mounting, lease permission or electrical suitability.