I don’t know it seems they want you to have an airtight house, no chimney, and furnace plumbed to the outside that can plug up in winter and the carbon monoxide reports keep climbing which was unheard of years ago.
Funny thing is, we never used to get reports of elevated radon gas in homes, but in many areas we had abnormally high incidences of cancer, especially lung cancer.
Similarly, we didn't used to get so many reports of carbon monoxide reporting either. But so many people would get "sick" in the winters and it was attributed to seasonal flus and such.
Then we started putting sensors in homes, and undertook extensive research.
The government had a huge issue when Mike Homes stated publicly that R2000 homes were bad, and that new homes were too tight. It took many years and many educated people to beat into Mike's brain why he was wrong, and now he is a convert.
I am not claiming that tight homes are perfect, in fact many tight homes are far worse than older leakier homes, because the builders made fundamental errors due to their lack of knowledge in building said homes. But I'd far prefer a properly built new tight home. But they are not easy to get right. And yes, sealed combustion appliances when installed poorly are prone to plugging with ice. It is sad really when manufacturer's engineers design a system to drain condensate but a slub in the field installs them incorrectly.
Not to say engineers are perfect by any means. When condensing furnaces first started wide spread introduction into the Canadian marketplace, Carrier had major major issues with furnaces shutting off and venter motors burning out. Engineers were scratching their heads going WTF we never had any of these issues in our extensive lab testing. Too bad these clowns never had seen an actual Canadian basement or furnace installation. Basement floors are sloped. An installer removing an old oil furnace yanked it out and stuck in the new gas furnace without a second thought. And rightly so, they'd been installing gas furnaces this way for decades.
The first year the Carrier SX furnace came out 50-75% of them had issues. Carrier dealers I know called the them sucks furnace.
The issue was that the drainage was poorly designed so it only worked if the furnace was within 1-2 degrees of level. Otherwise the fan housing and drainage box would fill with condensate, and the fan blades would splash in the condensate making noises that alarmed the owners. Eventually the furnace would fail from a pressure switch in the venter assembly, and or the venter motor would burn out.
This required the training of every carrier dealer installer and service mechanic across Canada, and much of the US. It led to design revisions on all future models to improve drainage of condensate.
Over the last 30 years of housing research and improvements in construction and materials, and resulting code requirement changes and increases in required energy efficiency levels and you create thousands of individual issues like this example. I'm privy to literally hundreds of discovered issues and the stories behind their discovery and eventual solution.
I can say, given the players involved in the field, the climate, the weather, the bureaucrats, the greed, the speed of the evolution of housing technologies, I'm pleasantly surprised our housing isn't total garbage