The Solarholm Glossary of Home Solar and Battery Terms

Quality panels are typically warranted for twenty-five years or more and usually continue producing at reduced output well beyond that. String inverters generally have shorter warranties and are the component most likely to need replacement within the life of the array, while microinverters commonly carry terms closer to the panel product warranty. Batteries are commonly warranted for around a decade, subject to cycle or throughput limits.

Yes, though at reduced output. Panels respond to light rather than heat, so a cold, clear winter day can be surprisingly productive, while overcast skies reduce generation substantially. Annual estimates already account for local weather patterns, which is why the same array produces different totals in different regions.

An owned system in good condition with transferable warranties is generally viewed as an asset by buyers, particularly where electricity rates are high. A leased system or a power purchase agreement can complicate a sale because the buyer must qualify for and accept the contract. Documented production history strengthens the case in either situation.

There is no typical answer, because size should follow your actual consumption, your utility's export rules, and your plans for electric vehicles, heat pumps, or a battery. A designer should model at least a year of interval data from your utility rather than a national average. Under net billing, a modestly smaller system often delivers a better return than a larger one.

A standard grid-tied system without a battery shuts down when the grid fails, for the safety of utility workers. To keep power on you need a battery paired with a backup gateway or transfer arrangement that lets the system island from the grid. Even then, only the circuits included in the backup design will stay on.

Surplus power flows to the grid and is credited under the terms of your interconnection agreement. Under net metering it offsets your consumption at full retail value; under net billing it is credited at a lower rate. A battery lets you store the surplus for evening use instead, which is why storage becomes more attractive as export rates fall.

It changed the comparison. The residential clean energy credit a homeowner could claim on a purchased system, Section 25D, is not available for expenditures made after 2025. Third-party owners such as lease and power purchase agreement providers may still claim the commercial credit under Section 48E on systems placed in service through 2027, subject to sourcing rules, and some pass part of that value through in their pricing. That narrows the cost gap that once favored buying outright, but a lease still leaves ownership and much of the long-term savings with the provider and can complicate a home sale. Model the full-term cost of each path and confirm the tax position with a professional.

Very little in most climates. Rain keeps panels adequately clean, and there are no moving parts. Occasional professional cleaning may help in dusty or pollen-heavy regions, vegetation should be kept trimmed to preserve the original shade analysis, and monitoring data should be checked regularly so that a failing component is caught early.

A properly installed system with flashed and sealed penetrations should not damage a roof, and panels can actually shield the shingles beneath them from weather. Problems arise from poor workmanship or from installing on a roof near the end of its life. Ask how penetrations are sealed and what the installer's workmanship warranty covers.

If the roof has less than a decade of life remaining, replacing it first is usually wise, because removing and reinstalling an array later adds cost and risk. Do not rely on the solar company's site survey alone; hire a roofer with no financial stake in the solar sale to inspect the surface, the flashing, and the decking from the attic, and ask for a written estimate of remaining life before the panels go on.

A kilowatt is a rate of power at a moment in time, like the speed of a car. A kilowatt-hour is an amount of energy accumulated over time, like the distance traveled. Array sizes and battery output are in kilowatts; production, consumption, and battery capacity are in kilowatt-hours.

It depends on the roof. On a large, unshaded roof, a strong mid-tier panel may deliver similar lifetime energy for less. On a small or complex roof, higher efficiency lets you fit the capacity you need, and a slower warranted degradation protects output in the later years that matter most for payback. Judge the whole system, not the panel in isolation.

Neither is better in the abstract; the timing of the storage decision usually settles it. DC coupling through a hybrid inverter is the more efficient and tidier path when the battery is planned from day one, at the price of committing to a compatible equipment ecosystem. AC coupling gives the battery its own inverter, adds a small conversion loss from handling the power twice, and attaches to nearly any array while leaving the original inverter in service. Ask the installer to state the round-trip efficiency and the compatibility assumptions of whichever design is proposed.

Proposals differ in equipment tier, inverter architecture, design assumptions about shading and roof usability, labor models, overhead, and sales commissions. Normalize them to price per watt, projected production per watt, warranty terms, and the assumptions behind the savings estimate before drawing conclusions about which is the better value.