I have been working a job on a high-efficiency “huge house” sitting on top of a hill.
When there is a fire in the first floor fireplace, smoke gets sucked down an adjacent flu (in the same chimney) from three stories above and discharges smoke into the master bedroom through the fireplace there.
Contractors have yet to come to grips with this new technology without abandoning old construction technique.
Also, last week we had a report hit the newswire were someone’s kid had a hamster that died. They replaced the hamster and it died two days later so they got a mouse which died in two hours! Hazmat was dispatched to find high levels of CO2 (enough to kill a small rodent). Not CO, CO2. There was no fossil fuel appliances anywhere in the building. The house was built to high-efficiency standards and obviously a design to ensure rodents will not infest the residence!
We have yet to fully see this high energy efficiency technology rare its ugly head.
As far as this situation is concerned, anyone that spends the effort and money on a high-efficiency home and installs an 80% furnace in this manner is a total idiot. This furnace does not have a supply air connection that can be piped to the exterior.
Installing combustion air vents from the attic to the exterior wipes out the entire principal of insulating the roof versus the ceiling. It will also produce the moisture issues at in the attic as those who misunderstand a sealed attic design pointed out concerning moisture entering attic from the finished space below. Adding vents into the attic is not a proper method of mediation.
If properly installed, a sealed attic will not have any problems with moisture levels from the interior of the house, if these moisture levels are properly maintained and someone doesn’t do something else stupid. Improper use of humidifiers, failure to use installed ventilation equipment in bathrooms etc. Buy the way, HVAC equipment does not produce moisture inside the house when installed inside the house unless it’s leaking all over the place.
Kevin, I think you did good by reporting what you saw, even though you did not have the tools to determine if this is actually a hazardous condition. This evaluation is not part of home inspection and not your job. In principle, this could be a very hazardous situation if we take into account other conditions built into the house.
Whenever I see a high-efficiency home or building, the hair automatically stands up on the back of my neck!
I have not been doing many home inspections since Thanksgiving, but I have been booked up with building performance issues. Surprisingly the majority of them are high-efficiency homes that are improperly built. Maybe it’s just that those homeowners expect more and recognize these problems, however I find it interesting at the ratio of buildings with problems in relation to the efficiency standards that the buildings are built by.