There are a few things to keep in mind about guesthouses in Chiang Mai though. First, there are so many of them that there is currently more rooms than there is demand. This means the prices are really low. There are plenty of comfortable guesthouses available in the $5-$10 (200-400 baht) per night range. Your price per day even at the most comfortable of guesthouses will be reduced even further if you pay for a week or a month.
You’ll do better to compare prices and reserve your guesthouse room online or by phone ahead of time, or go look for a guesthouse on your own when you arrive. If you end up in Chiang Mai at the airport or bus terminal from Bangkok, many locals will come up and offer to bring you to a guesthouse. These folks get a share of every new customer they bring to the guesthouse, and you usually end up paying the price if you take them up on their offer to help you.
If you get into town without reservations, you might be better off hitting a pub or restaurant first and finding some local expats to chat with and get their recommendations.
Also, guesthouses in Chiang Mai are usually private, sometimes with shared toilets and showers though. Rooms with a air conditioner are more expensive than those with just a fan, but not by much. If you’ve been travelling south of Chiang Mai, the weather will seem much cooler to you though during most of the year and a fan room might be more than suitable here.