Ventilation is your friend, along with a CO detector.
CO detectors are required in new home construction. They are usually a combo unit that doubles as a smoke detector and a CO detector.
One must be placed within 10 feet of bedroom doors and mechanical areas.
In a remodeling situation if a wall is opened up, then code dictates that that floor must now have a Smoke/CO detector installed.
It's easy guys, just go to your local big box store or Washington Post Amazon and purchase a couple Smoke/CO combos to replace your existing single smoke detectors.
Indoor heater or no, it's a good idea to do it now.
