Thank you Jay J., after all the shopping and research it does indeed appear that we will have to get a gas stove that is vented outside, if we get anything at all. Just too chancy spending all that money on something that may or may not cause a reaction, and we wouldn't know till it was installed and running. The unit will sit in our lower level, below grade family room (very cold in winter). Hopefully even a vented gas stove would still reduce heating costs because our main furnace would not be struggling to heat the lower level so much.