PLUGWATTS / SMALL SOLAR GUIDES
Is plug-in solar worth it for your home?
By PlugWatts editorial · Reviewed September 15, 2026 · AI-assisted research and review
Plug-in solar is worth investigating when the electricity you can use justifies the complete cost of the project. A low kit price is not enough: sunlight, daytime demand, meter treatment, any installation work and how long you expect to use the system can change the answer.
Below are three hypothetical scenarios that show how to compare a proposal. They are not market prices, Maryland production forecasts or promised savings. Use the downloadable worksheet to replace every assumption with evidence for your situation.
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Start with a complete cost
Ask for the price of the exact configuration, including panels, inverter, mounting, specified cables, delivery, taxes and any required professional work. List optional batteries separately. A battery changes cost, losses and operation; it needs its own comparison.
For your private record, separate a written quote from an allowance you have guessed. Include recurring costs or replacement allowances where appropriate. Do not count an incentive until you have verified that your project and purchase date qualify.
Turn usable energy into value
For the simplified, no-battery examples here:
Annual net value = self-consumed solar energy × avoided electricity rate + export credit − annual costs.
“Self-consumed” means solar electricity used at home as it is produced. It is not necessarily all of the panel's generation. Use only the bill charges that actually decline when imports decline; fixed monthly charges do not disappear in this model.
The avoided rate is a user-supplied assumption. On a time-varying tariff, calculate value for the periods when solar actually replaces grid use rather than applying the highest rate to every kilowatt-hour.
Three scenarios, the same assumed generation
All cases assume 1,000 kWh of annual AC generation, no battery, a flat avoided rate of $0.20/kWh, zero export credit and $0 annual ongoing costs. The assumptions are chosen to isolate the effect of self-consumption and upfront cost. They are not derived from a measured installation or a local quote.
| Scenario | Upfront cost | Used at home | Annual net value | Simple payback |
|---|---|---|---|---|
| A: More daytime overlap | $1,000 | 800 kWh (80%) | $160 | 6.25 years |
| B: Less daytime overlap | $1,000 | 400 kWh (40%) | $80 | 12.5 years |
| C: Higher complete cost | $1,800 | 800 kWh (80%) | $160 | 11.25 years |
The calculations are straightforward: case A uses 800 × $0.20 = $160 per year; $1,000 ÷ $160 = 6.25 years. Case B saves half as much despite identical assumed generation. Case C adds upfront cost without increasing useful energy.
These results are simple payback, not a lifetime return. They omit financing, discounting, degradation, rate changes, repairs, replacement and relocation costs. Zero ongoing costs is a simplifying assumption, not a statement that ownership is cost-free. A long payback is not proof that equipment will remain usable for that period.
Try to make the result worse
A useful estimate should survive less favorable assumptions. Starting from case A:
- If annual generation is 25% lower, with the same 80% self-consumption fraction, value falls to $120 and simple payback becomes about 8.3 years.
- If the avoided rate is $0.15/kWh, value is also $120.
- If annual costs are $20, net value is $140 and simple payback becomes about 7.1 years.
- Over three years, the original $160 annual value totals $480 before the excluded costs. A three-year stay would not recover the $1,000 cost at that address. Reuse after moving is a separate, uncertain assumption.
When annual net value is zero or negative, there is no positive simple payback under those assumptions. Do not display a misleading number by dividing through a loss.
Where your inputs should come from
Generation: use a documented estimate for the proposed configuration, location, orientation, shade and losses. PVWatts is a starting point for estimating grid-connected PV production, not a certification or a promise of bill savings. Its results depend on inputs and modeling assumptions. It does not establish that a small balcony configuration is eligible or that your home can use all its energy. PVWatts calculator.
Self-consumption: compare production timing with household demand using appropriate interval data where available. Annual electricity use alone cannot show daytime overlap. With no reliable estimate, compare several explicit assumptions instead of selecting the most favorable one.
Export treatment: ask your utility. Maryland's PSC warns that meter behavior can change how excess energy is recorded. Zero credit in our examples is not a guarantee that export has no other billing effect. Resolve the actual arrangement before using the examples as a purchase basis. PSC guidance.
When to pause or choose another option
Pause if the quote excludes necessary work, the output estimate ignores shade, certification is unresolved, or the result depends on credit the utility has not confirmed. If there is no usable space or you expect to move soon, compare renter alternatives.
A favorable spreadsheet cannot approve equipment or a site. Once the economics make sense, use the Maryland guide and Check to organize the remaining conditions.
Method and corrections
PlugWatts created these hypothetical examples and checked their arithmetic. No retail-price survey, location-specific generation simulation, product test or personalized financial assessment is represented. Research and editorial review were AI-assisted. There are no affiliate links or paid recommendations. Report calculation or source issues through About & corrections; do not send private bills or account numbers through that form.