Yes I considered that and I was curious, so I looked it up. It seems the federal government estimates a lower bound of 25 people injured or killed in fires due to bars on windows every year. All things considered, I think that's not so extreme, although the risk should be weighed against the relative risk you believe burglary poses in your neighborhood. 25 per year is several orders of magnitude lower than the number of victims of violent crime stemming from home invasion, although many neighborhoods will not embody those averages.
There are other solutions as well. Many window frames are designed to permit the window to be cracked open but not opened fully, to prevent ingress while still allowing egress (either by disengaging the mechanism or by breaking the window if necessary.) Such a mechanism can often be retrofitted to an existing window frame for no more than a few dollars. I've seen people create their own using a short length of dowel rod placed such that it prevents the window from opening fully. There are also a variety of purpose made mechanisms on the market.
These mechanisms are not as secure as bars on windows, but about as secure as a normally closed and locked window. The payoff for less security is enhanced aesthetics and fire safety.
There are many reasonable solutions to bedroom ventilation.
https://www.usfa.fema.gov/downloads/pdf/publications/tr-138....
https://www.bjs.gov/content/pub/ascii/vdhb.txt
There are other solutions as well. Many window frames are designed to permit the window to be cracked open but not opened fully, to prevent ingress while still allowing egress (either by disengaging the mechanism or by breaking the window if necessary.) Such a mechanism can often be retrofitted to an existing window frame for no more than a few dollars. I've seen people create their own using a short length of dowel rod placed such that it prevents the window from opening fully. There are also a variety of purpose made mechanisms on the market.
These mechanisms are not as secure as bars on windows, but about as secure as a normally closed and locked window. The payoff for less security is enhanced aesthetics and fire safety.
There are many reasonable solutions to bedroom ventilation.