Before you decide
Is my roof suitable for solar panels?
The short answer
Four things decide it: which way the roof faces and at what pitch, how much shade falls on it during the middle of the day, how much life the roof covering has left, and whether the structure can carry the array. Of those, remaining roof life is the one that most often changes the plan rather than the price.
In order of how much each one matters
- Shade. Panels are affected disproportionately by partial shade, and a single chimney or tree shading part of the array at midday costs more output than the area it covers suggests. Module-level electronics mitigate it and do not eliminate it.
- Orientation and pitch. In the northern hemisphere a south-facing slope is the best case; east and west facing arrays produce less overall and can suit a household that uses power in the morning and evening. North-facing is generally poor.
- Roof age and condition. A roof within a few years of replacement should be replaced first, because removing and reinstalling an array later costs substantially more than doing it in the right order.
- Structure. Most roofs carry a modern array without difficulty; some need an engineering assessment, and that is normal rather than a warning sign.
- Available area free of vents, skylights and setbacks required by fire codes, which vary by jurisdiction.
What to have ready for an installer
The age and material of the roof, whether it has been replaced, roughly how much electricity you use across a year, and a note of what shades the roof at different times of day. An installer who asks for none of that before producing a design has produced a template.
If the roof is due for replacement within a few years, get the roofing quote before the solar quote. Doing it in the other order is the most expensive sequencing mistake in this whole subject.
Also asked
Do solar panels work in winter?
Yes, and they produce less, because the days are shorter and the sun is lower. Cold itself is not the problem — panels are slightly more efficient at lower temperatures. Snow cover stops production while it sits, and it usually slides off a pitched array. Annual production is what matters, and any credible design models it across the whole year rather than a single day.
Do I need to replace my roof before installing solar?
Only if it is near the end of its life. A sound roof with many years left does not need replacing. The reason this comes up so often is that removal and reinstallation of an array for a later reroof is a real and avoidable cost.
The long version
How to choose a solar installerThe company matters more than the panel. How to weigh a local track record against a national sales operation, and what to check before you sign.
General information about solar and about hiring, not advice about your roof or your tax affairs. Incentives, net metering and contractor licensing are set federally, by state, and by your utility, and all of them change. The authority that publishes the rule is the current answer.