Card condition and temperature storage effects

ID cards left in environments with extreme temperatures degrade faster than cards stored at room temperature. Having seen the effects of summer car interiors and cold wallets on different card types, here is what the data shows.

Heat exposure

The interior of a car on a hot summer day can reach 60-70°C (140-160°F). PVC cards begin to deform at around 60°C. Polycarbonate cards have a higher thermal stability — they begin to soften around 130°C and show no significant deformation at car-interior temperatures. However, adhesive layers in composite cards (including some holographic overlays) can separate at lower temperatures than the card substrate itself.

Cards left on a dashboard in direct sunlight accumulate UV exposure in addition to heat. UV exposure can bleach certain inks over time, particularly on the printed side of the card. The degradation is slow and cumulative — a few hot days will not noticeably affect a card, but regular sun exposure over months shows up as color shift in lighter printed areas.

Cold exposure

Cold temperatures make PVC cards brittle and more prone to cracking at the edges when flexed. A PVC card taken directly from a cold environment and flexed sharply may crack where a warm card would not. This is more relevant for cards carried in outdoor winter conditions than for stored cards. Polycarbonate cards are less susceptible to cold-induced brittleness.

Ideal storage conditions

Room temperature (15-25°C), away from direct sunlight, stored flat without pressure bending. For cards in daily use, the environmental exposure is unavoidable — a card in a wallet in your pocket experiences daily temperature and humidity cycles that are well within the tolerance range. The concerns above apply primarily to cards stored long-term or to situations of extreme temperature exposure like car interiors in summer.

For long-term collection storage, maintaining consistent room temperature and avoiding humidity fluctuations matter more than specific temperature targets within normal residential ranges. The most common storage damage in collections comes from repeated cycles of temperature change — storing near heating vents, exterior walls, or in vehicles — rather than from steady conditions that are slightly above or below ideal. Consistency is the primary environmental variable to control.