carbon monoxide: Carbon Monoxide Detector Placement - 10/08/18 04:06 AM
Carbon monoxide detector placement.
That title surrounds a question I get a lot during home inspections.  And this one -
Is carbon monoxide lighter or heavier than air?
Of course, any time you have gas appliances or a wood-burning fireplace, you should have at least one carbon monoxide (CO) detector in the home.
CO is odorless, tasteless and DOES NOT GIVE WARNING that it is being produced or building up.
And, is it lighter or heavier than air?  Which means, does it rise or fall when produced?
Since the molecular weights of gases differ, what makes them move is convection.  If a gas is released because of … (55 comments)

carbon monoxide: "By Law" The "Technicians" Had To Shut Down The Water Heater - 10/09/15 05:54 PM
When he called me, my neighbor said, "By law the technicians had to shut down the water heater."
An HVAC company went by my neighbor's house to perform a fall check up and service.
While there they said they would "take a look" at the water heater just as a kindness.
Turning up the temperature to fire it up, they drilled a hole in the exhaust flue 3' from the hood, and inserted a CO probe.
It read 143.  The "technicians" were horrified.
They said  that by law they had to shut down the water heater.
They said  it needed to be replaced immediately.
They said  that something … (31 comments)

carbon monoxide: A Scary Phone Call - "You Ruined The Sale Of My House!" - 06/06/14 08:39 PM
After hardly saying hello, the voice on the phone yelled, "You ruined the sale of my house!"
He then went on in a rant that ended with, "I know where you live."  It was said in a very unkind manner.
I have heard this sort of thing before.  People upset that I identified something on their house that "cost" them the sale.
Frankly, and properly said, a home inspection doesn't make or break the sale of any house.  It is merely observation of the house on the day on an inspection and reporting conclusions. 
But after hearing the threat I … (29 comments)

carbon monoxide: This Is Deadly Air Being Drawn Into The House - In Northern Virginia? - 11/16/13 09:54 PM
There'e no other way to say it - this is deadly air in being drawn back into the house - in Northern Virginia?
Say it ain't so!
Well it is.
A high-efficiency condensing gas furnace is a wonderful and extremely efficient appliance.  I wish my furnace was this efficient.
Most gas furnaces, like mine, have a flue which expel their exhaust through a metal flue extending through the attic and roof.  I am losing huge amounts of heat through my roof!  And my furnace is only capturing, and using, a percentage of the heat generated by the furnace to send through … (35 comments)

carbon monoxide: No Matter The Code, Or General Practices, I Don't Like This - 05/22/13 08:56 PM
One of the most confusing, and changing, practices is how to exhaust a high-efficiency, direct vent furnace. 
But, no matter the code, or general practices, I don't like this. 
These are enclosed systems.  One recent practice that I don't like is that they take indoor air.  Always I would prefer to see outdoor air as they suck in a lot to make the system work.  Why take in so much indoor air when it is not necessary?
But, the exhaust is what seems so confusing.
The tubing pointing down is drawing air in.  The tubing pointing out is the furnace … (38 comments)

carbon monoxide: With HVAC Vents, Do A Lot Of Small Holes Let Out Less Carbon Monoxide? - 05/08/13 08:08 PM
So, the age-old question - with HVAC vents, do a lot of small holes let out less carbon monoxide?
This is a house with a brand new gas HVAC system and gas water heater.  They were both high quality and in good shape.  Their efficiencies and installation all met all the recent codes.
But the venting through the house, and their connections were original, and nearly 40 years old.
I was disappointed to see that the HVAC installation company paid no attention to the venting.
You can see that the main exhaust stack is rusting, corroded and has the infamous brown … (13 comments)

carbon monoxide: But They're Really Small Holes - 10/17/12 11:57 PM
I got a response back from a recent home inspection - "But they're really small holes."
For sure, I am not going to say if this comment was from a seller or listing agent disagreeing with me.  It was, but I am not going to identify from whom.  For sure, it was a very out-of-place, even stupid, comment.
Those are the small holes.
They are located where a boiler exhaust vent attaches to the main exhaust stack which proceeds from there through the roof.
Certainly those holes represent a carbon monoxide danger to the house.
Has CARBON MONOXIDE been a problem … (41 comments)

carbon monoxide: When It's Flu Season, It's Flue Season - 12/17/11 08:38 PM
When it's flu season, it's flue season - the furnace flue that is.  Gas and oil systems utilize a flue to exhaust their combusted gases out of the house. It's simple really - various tubes connect to provide a contained, directed flow of furnace exhaust outdoors.
When an older system is replaced in an older house, typically the entire flue system is replaced at the same time.
It's just smart to do that.
Let me do some what ifs...
What if the sales literature states that the HVAC system was completely replaced in August?
What if this is the first winter … (35 comments)

carbon monoxide: The Whistle While You Work Furnace Vent - 11/01/11 09:30 PM
This is the story of the Whistle While You Work Furnace Vent.
One of my practices as I enter a house to do a home inspection is to immediately turn on the HVAC system.  When it is cold, I turn on the furnace. 
Descending to the basement I thought I heard a whistle.  The house wasn't occupied, so I wondered what could be causing it.  Trying to follow the sound, I was led to the furnace room.
Opening the furnace room door, the sound was even more pronounced.

Still looking, my ear directed me toward the metal furnace vent tube, … (29 comments)

carbon monoxide: Flipper Forgot Step Two! - 10/16/11 09:48 PM
Sometimes the job isn't done until it's done!  Some things take more than one step and this time Flipper forgot Step Two!
Step One was to install a new water heater.
And it was done well - there are a few things to look for and they were present.
Okay, it was small and really inefficient, but new!
Well, he used the old plumbing, including the gas shut-off valve being on the wrong side of the sediment trap, but we've already had that lesson.
You can see that's been there for a while!
Would he take the time to replumb the … (46 comments)

carbon monoxide: Pet Peeves - 09/02/11 12:08 PM
All home inspectors probably have their pet peeves.  My biggest involve carbon monoxide.  PVC vents that I think are too close to windows or doors and furnace/water heater vents through the roof that are very short and vulnerable to back drafting are two that come to mind.

I was reminded of this the other day on a one-year inspection.
All of the houses had the high-efficiency furnaces with PVC exhaust venting.  And all of the houses looked like the photo on the left.
Manufacturer recommendations say, depending on the … (17 comments)

carbon monoxide: "Where Should I Put A Carbon Monoxide Detector?" - 03/17/11 11:19 PM
"Where should I put a carbon monoxide detector?"
That is a question I get a lot during home inspections.  And this one -
Is carbon monoxide lighter or heavier than air?
Of course, any time you have gas appliances or a wood-burning fireplace, you should have at least one carbon monoxide (CO) detector in the home.
CO is odorless, tasteless and does DOES NOT GIVE WARNING that it is being produced or building up.
And, is it lighter or heavier than air?  Which means, does it rise or fall when produced?
Since the molecular weights of gases differ, what makes them … (24 comments)

carbon monoxide: Whistle While You Work - 03/15/11 11:37 PM
The house is old but the HVAC system is very new.  The compressor outside said 2009, so it is a good bet the indoor units are similarly new.  They were.
Entering the furnace room, not only was the furnace and AC equipment new, but so was the water heater.
Both exhaust flues were newer also.  And they both entered into an older double flue, which had been there for some time.
The double flue was very long, approximately 15', and while I am not a fan of exhaust flues hitting another at a 90 degree angle, it is permitted here.
However, … (57 comments)

carbon monoxide: "Furnace Has Had An Annual Service Contract" - 01/01/11 10:22 PM
I can tell you that when a home inspector sees a service sticker on an HVAC unit, and the service is up to date, that inspector will feel a little bit better about the system.  Even if it is an older system, as on this house.
And, knowing that the system is old, the agent thought to feature the fact that the diligent homeowners had a regular service contract.  Prominent in the list of features was listed, "Furnace has had an annual service contract."  And, normally, that is great information.
The key word however is system.  If a company is going … (51 comments)

carbon monoxide: Bird Condo - 12/29/10 09:57 PM
As houses sit for months, and in the case of this house over a year, conditions can develop that buyers might not consider.  This one photo is reason enough to get a home inspection!  This buyer told me he had been to (and since there was a combo box on the door INSIDE) the house many times.  He had not noticed a lot of what I had on my extensive report, but certainly had not noticed this.

Unfortunately it was a very cloudy and dark day, so this picture may not do this circumstance justice.
This is the gas water … (44 comments)

carbon monoxide: Don't Turn On The Furnace - 11/18/10 10:56 PM
On a recent new construction inspection I arrived much earlier than my clients.  I like to do that.  When they arrive I can greet them and introduce myself, and mention a couple of things about the house.
Usually the supervisor comes to the house when he sees me.  Often he will say something like, "Well, you won't find anything wrong with this house!"  This supervisor was no different.
I was inside this house about 10 minutes when I found three serious problems.
This is one.
The house has two furnaces, the lower level being a high efficiency, condensing gas furnace.
Very … (126 comments)

carbon monoxide: Carbon Monoxide Poisoning - 05/09/10 12:13 AM
I was called by someone who found me on line.  She wanted me to find the solution to a problem.
It seems the three kids in the family have all moved on, with Mom still living alone in the old house they grew up in.  Until recently.  She was "continually sick with the flu" and only felt better when she went to visit one of the kids, all nearby.  Their conclusion:  the house was making Mom sick and they moved her out to figure it out.  That could really be true.  In this case it was true.
They checked with an … (71 comments)

carbon monoxide: There Was A Train In The Living Room - 03/22/10 11:01 PM
Nothing unusual - very old house, chimney in the center which passed through the roof, thermostat in the dining room.
Doing my normal routine, I turned on the dishwasher and oven, and found the thermostat to turn on the furnace.  I noticed oil tank lines on the outside of the house, so I already knew the house had an oil furnace.
About a minute later we heard what sounded like there was a train in the living room!  Well, you don't hear that every day!
Looking around, here is what I found:


carbon monoxide: New Boiler, Old Chimney, Missing Hole - 11/15/09 09:05 PM

Old house, new boiler, new flue, new connection to the old chimney.  All good.
Except for a couple of things.
First, the hole beneath where the flues connect to the chimney has been filled with mortar.
That is not good.
Second, the new connection to the chimney required that the old connection from the water heater inclines downward. That impedes exhaust drafting.
That is not good, either.
On top of the hip roof, the chimney is on the side of the house.  It is very high, too high for most ladders.  And dangerous to access from the roof side.  … (10 comments)

carbon monoxide: Hide and Seek - 08/19/09 08:15 AM
Every inspection probably brings the opportunity to teach and learn.  A recent inspection was no different.
This is the HVAC unit of a two-story, 60 year old house.  It was manufactured in 1993.
While I won't go into everything possible here, there are some things worth mentioning.  They are all correctable.  They are all important.
The house sits on a masonry foundation with a "continuous crawl space perimeter."  That means that the crawl space is the footprint of the entire house.
The crawl space is used for everything from plumbing to drainage to HVAC return ducts, electrical, gas lines, etc.  Some … (11 comments)

Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) Rainmaker large

Jay Markanich

Home Inspector - servicing all Northern Virginia

Bristow, VA

More about me…

Jay Markanich Real Estate Inspections, LLC

Address: Bristow VA 20136

Office: (703) 330-6388

Mobile: (703) 585-7560

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An experienced home inspector's look at current home inspection events and conditions along with his useful recommendations.




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