Don't know about on the counter, but I've had peppers last for months in my fridge. Maybe check them periodically and remove any bad ones? What's the expression...one bad apple spoils the bunch?

Keep them away from other ripe fruit. The ethylene in ripe bananas, tomatoes and other fruit may cause them to ripen faster (so, keeping them away from those may help). Keeping them cooler may also help to keep them unripe longer.

@albert_135 Our peppers last a really long time unrefrigerated, but they do often change color outside the refrigerator. Thinner peppers will dry instead of going bad unrefrigerated here. Thicker ones generally stay good until they start to dry or longer, here. My area is semi-arid. I'm not sure if it's a good idea to keep them unrefrigerated for long periods in humid areas or not.

For future reference, there is supposed to be a green-when-ripe Habanero. It might turn a little yellow eventually, but I imagine it stays green longer than usual.

Apparently the ''beautiful green'' we found so fascinating dulls very fast after harvesting. In just a matter of a few hours the peppers are just lovely, yea, even still beautiful, but the special green of that first impression is gone.