Hard to say. Warranty covers "normal usage", maybe defined by mild californian weather.

Severe heat or cold wrecks havoc on battery life. Even in southern Canada I am certain you won't get anywhere near the 8 full years, now imaging you live anywhere that gets down to -30C frequently during the winter.

That's my biggest concern right now, heating an electric car uses the battery as heat is NOT a byproduct of an electric engine. Very impractical in the winter.