Path-Q Solar
Should I size solar to cover all of my annual electricity use or only part of it?
Answer
Neither target is automatically best. Size for the share of consumption that provides acceptable value after considering production timing, export treatment, future loads, roof constraints, budget, and the likelihood of remaining at the property. Annual production equal to annual use does not mean the home will be independent of the grid.
Key points
- A partial system may offer better economics when exported energy is less valuable than onsite use.
- A larger system may make sense for planned electrification, such as a heat pump or electric vehicle.
- A system designed around current use can become undersized if consumption rises.
- Grid connection and billing arrangements usually remain relevant even with annual energy matching.
What it depends on
- Current and expected future electricity use
- Hourly load and solar-production overlap
- Export compensation and tariff structure
- Budget, roof capacity, and ownership horizon
Risks and trade-offs
- Oversizing can increase cost and excess exports without proportional benefit.
- Undersizing may require a later expansion that is technically or financially less convenient.
- Annual offset percentages can obscure seasonal deficits and surplus production.
Information you may need
- At least 12 months of electricity use
- Planned electric appliances or vehicles
- Export and billing terms
- Candidate system prices and production estimates
Your next step
What to do next
Compare partial-offset, current-use, and future-use designs using the same assumptions for cost, production, export value, and expected ownership period.
Path-Q
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