Hi there! After reading this post I just wanted to add a comment about carbon monoxide - it is a gas that is deadly to both pets and humans, plus there is no way to know if you have a carbon monoxide leak in your house until it is too late- unless you have a CO2 alarm. I found out lots of information from this website by a company called corgi homeplan (Carbon Monoxide - How safe is your home?) and I have had a CO2 alarm installed in my house as I have 3 dogs and 2 children (a bit of a mad house - I know!) but I thought it would be the responsible thing to do. I hope you find this helpful!