a carbon monoxide detector can actually be pretty useless in an ice hut situation because the amount that is lethal over say a ten hour time span will not set off most detectors. Enough to kill you in an hour will however set it off. Sounds like the OP might be looking to heat a sleeper hut not a pop up. Many people use a two burner gall stove with a chimney welded on it or if its a bigger one a gas fireplace. Ventilation is still important.
Guys build a hunt camp and seal it up to tight then turn down the stove to go to sleep and they are all found tucked in nice and tight in their sleeping bags dead, is a common story from the old days.
