Commonly Mistaken and Misused Terms, Part II

Below is a list of commonly misused or mistaken terms that I hear every day - sometimes from other home inspectors, but mostly from clients.  This will hopefully clear up some misused or mistaken terms.  Feel free to add to the list.

Direct Vent A direct vent gas appliance takes all of it's air for combustion directly from the exterior.

• Furnace For a furnace, you'll see two plastic pipes running to the furnace - one for air coming in, one for combustion gases going out.   A condensing furnace with only one plastic pipe is not a direct vent.
• Gas Fireplace For a decorative gas appliance (aka - gas fireplace), you'll typically see a metal termination at the exterior of the home, where the outer 'ring' brings air in, and the inner ring exhausts combustion gas. The photo at right shows the termination for a gas fireplace.
• Water Heater Direct vent water heaters are not common in Minnesota - I think I've seen two in my life.  Powervent water heaters are.   A powervent water heater will have a single plastic pipe to force the exhaust gases to the exterior.

Attic - Attics are defined as "The unfinished space between the ceiling joists of the top story and roof rafters".  Many people refer to attic spaces as 'crawl spaces', but 'attic' is a much more specific term.

Fuse Box Most people are referring to the main panelboard when they say this, and most have circuit breakers, not fuses.


Fire Wall This is a term that only applies to commercial properties.  Most people are referring to the fire separation wall between the house and garage at a single family dwelling when they use this term, but this is not a fire wall.  A true fire wall completely separates parts of a building so that one portion may collapse and burn to the ground in the event of a fire, while the wall remains intact.  You won't find a fire wall in a single family home unless you're referring to the internet connection.


Sheetrock®, Durock®, Romex®... They're all brand names, just like Kleenex®.  Better terms would be gypsum board or drywall, cement board, and NM (non-metallic) wire, respectively.





Overflow Pipe I've heard many people use this term to refer to the pipe that gets connected to the temperature and pressure relief valve on a water heater.  I really don't know what the best term for this pipe is, but it's certainly not an overflow pipe.  I awkwardly refer to it as the "temperature and pressure relief valve discharge pipe" or "relief valve discharge pipe".
Joyce Joist
Acrost Across
Heighth Height  (thank you to Matt for this addition)
Footer Footing
House Geek Home Inspector

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspections


RELATED POST:  Houses Don't Need CO2 Alarms

Houses Don't Need CO2 Alarms

There are many common misconceptions about furnaces, water heaters, and carbon monoxide that I hear repeated on a daily basis, and I’d like to clear a few of them up.


False: Carbon Monoxide is also called CO2.  Carbon Monoxide is CO. Carbon Dioxide is CO2.  (Mono = 1, Di = 2)


False: Cracked heat exchangers create CO.  CO is caused by incomplete combustion, period.  A cracked heat exchanger does not create CO.  A heat exchanger is the part of a furnace that transfers heat from the flames to the household air.  A functional heat exchanger keeps the household air and the combustion gases completely separate from each other.  If a furnace has a cracked heat exchanger, the combustion gases can mix with the household air.  It’s usually just a little bit, but this is still unacceptable, and it means the furnace or heat exchanger should be replaced.  The photos below show cracks in heat exchangers (click the photos for full-sized images).

   

False: Cracked heat exchangers can be fixed.  They can’t be fixed.  The heat exchanger or entire furnace needs to be replaced.



False: High CO levels = cracked heat exchanger.  See above.  We test the CO levels in the flue gas, which has nothing to do with a cracked heat exchanger.  Heat exchangers fail when the metal rusts through or when it cracks.  CO does not cause this.


False: High CO levels in the flue gas mean the furnace is leaking CO.  If there is a high level of CO in the flue gas, there is a potential for the exhaust gases to mix with the household air, or ‘leak’.  One way would be for the exhaust gases to backdraft, which means that instead of rising up and out of the house, they come back down the flue.  The other way would be because of a cracked heat exchanger.  If we find high levels of CO in the flue gas, we recommend immediate repair – it doesn’t matter if the gases are mixing with the household air at the time of the inspection or not, because this condition could potentially change at any time.  Higher CO levels can often be fixed.


False: Backdrafting at a furnace or water heater means CO is coming in to the home.Backdrafting means that exhaust gases are spilling back in to the home, rather than going up the flue.  A properly functioning water heater or furnace will not create CO, so you can’t say CO is coming in to the home unless you test the exhaust gases; we do this at every inspection.  Click here to see a video of me inspecting a furnace.  While backdrafting doesn’t mean CO is coming in to the home, this is still a potentially hazardous situation that requires immediate correction.  Backdrafting has the potential to allow CO in to the home, and will always contain CO2 (carbon dioxide), which can cause sickness and headaches in higher concentrations.

Wrong Term: Hot water heater.  Just 'water heater'.  The heated water that comes out is hot.
To summarize, high levels of CO need to be fixed, cracked heat exchangers need replacement, and backdrafting is never ok.  These three things are all independent, but a combination of these conditions is especially dangerous.  When using these terms, make sure you have them correct.  It makes a difference.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspections

RELATED POST: Commonly Mistaken And Mis-Used Terms, Part II