The warranty is usually 1 year. If you own a new, currently marketed model, go to the Canon USA website and check it. After you pick your camera model, you can drill into "Service and Support" and on that page you'll find a link ot "Warranty Terms".
For example, heres' the link to the Service and Support page for the EOS Rebel T5i:
I have seen extended warranties for things like printers and scanners... but I haven't seen extended warranties offered directly by Canon for cameras. There are a LOT of retailers who will sell you 3rd party warranties but I generally avoid extended warranties.
To set pricing, they work to determine the average rate of failure and the average cost of repair. The price is set so that they're profitable... which means that MOST of the time, you'll pay significantly more for the warranty than it saves you. If you happen to get that rare unlucky product that seems to break a lot and costs a lot to repair, then the extended warranty saves you -- but this is like playing the odds in Vegas... the odds are stacked in favor of the house... the house always wins.
If you took all of the money you would ever spend on an extended warranty for every product you ever bought and saved it in an account... then when that one rare product fails, you'd easily have enough money to just replace it or pay for the repair and would still have quite a chunk of money left over.
Oops - I missed the part about it being a refurb. Although... I'm actually pretty comfortable with a refurb. I feel like when you buy a "new" product, random units are checked for quality control. But when you buy a refurb, it was _specificially_ checked for quality and serviced appropriately.
I don't know if you've bought the camera or not yet. If you haven't, check out Adorama's VIP program. Doesn't cost too much and anything you buy though them for the following year has an additional year added to the respective warranty. A 90 day warranty becomes a year + 90 day warranty.
I bought a Sigma lens with a 3 year warranty through them. By having the vip plan, it makes it a 4 year warranty. I happened to buy the plan at the same time as the lens, but I've bought a couple of additional things through them and they get an added year to their respective warrantys automatically.
Check it out and see if it works for you or not.