Mock inspection clarifications

Hi all,

Started my first mock inspection, in Ontario, Canada.

I noticed romex wire touching the air ducts (more than a few times in the basement area), I read that due to them being insulated and the air ducts never reaching extreme temperatures that it’s not a problem, I wrote that wires should have some clearance around ducts (1 inch) to prevent possible Melting and then making the duct charged. Felt more just like a save my ass inclusion.

Next I mentioned how the ducts are not fastened via 3 screws or foil tape and the ducts have become loose due to that.

Lastly I saw a rusted wing nut on a supply register above the kitchen with green/blue residue. I stated condensation Is likely the culprit and recommended an appropriate qualified professional to fix the issues.

Lack of proper verbiage aside, what are your thoughts on my findings ?

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You are correct. That is not a problem.

Narrate what you see and recommend a qualified professional make corrections, as needed.


Morning, Paolo.
Hope this post finds you and your loved ones well and you are in good humor today.
Welcome to the message board.

Great questions!
Good observations! Good grammatical syntax.
Great photos!

you will be a very diligent inspector I predict.
Thank you for your questions.

Circuit cable clearance from conductive system materials.
1: A blocked supply duct and malfunctioning gas or electric furnace can reach very high temperature high enough to melt a circuit cable insulator jacket.
2: The expansion and contraction of forced air sheet metal ductwork can wear down the insulator jacket of a circuit cable to expose the current carrying conductor therefore the ductwork becomes current carrier.
Same as conductive plumbing pipes.
It is not just about heat.

All the best with your endeavors.
I will try to follow your posts.
Keep well.

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Morning, Larry.
Hope my posts finds you and your loved ones well.

Larry, I would review your answer.

Good morning Robert, are you sure about this?

The temperature of the air coming from a furnace shouldn’t be that high, I would say 100F at most. A blocked duct would be cooler than open one.

Some expansion/contraction could occur on a system with rectangular main trunk duct but I would be very surprised to see it on a round one.


Are they supply or return ducts?

All connections should be sealed and air tight. Preferably insulated (especially supply) to prevent energy loss and condensation. Remember, you are not performing and energy audit, but the condensation may cause damage.

The contact with the wiring is not an issue, but the wire should not be supporting the duct.

They are supply ducts.

So due to them being in the unfinished part of the basement, insulation around the ducts should be recommended due to condensation issues that could arise from the temperature differences?


Appreciate the feedback and the kind words!


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Yes, it is considered best practice for the reason you mentioned. (it is also now required but you do not have to mention that in order to make a recommendation) The other consideration is energy loss.

Possible narrative.
The visible supply ducts in the basement were not insulated. I also observed loose seams/unsealed seams. This may promote condensation issues or damage as well as promote energy loss. Some moisture staining and rust observed at xxxxx. Recommend evaluation for corrections by a qualified HVAC contractor.

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Awesome, I appreciate the feedback !

Hear me out…
Metal is metal. Conductive material is conductive material.There are 3 energy transfer methods.
Read what I said: “A blocked supply duct and malfunctioning gas or electric furnace can reach very high temperature high enough to melt a circuit cable insulator jacket.” “Melt or damage”
If the last branch is blocked forces more conditioned air supplied to open registers. Closed registers and blocked floor registers forcing more supply air to open registers.

David Anderson would explain it much better than myself.

Paolo- the first thing to note is that you’re in Ontario Canada. You have weather considerations and you have radon considerations because of regional conditions that we must consider when inspecting.

Nothing in the pictures you posted are “significant deficiencies” in accordance with home inspection standards. However, you should be obliged to add into your inspection report these things which you would be allowed to talk about which definitely would is be beneficial to the client. Remember, your job is to observe and report not analyze.

These installation practices appear to be in an older home (if it were constructed in Tennessee). The return duct is a metal pan against the floor joist. This is not any longer a preferred method of installation. It is also observed that the pan is separated from the joist in the picture. This will pull in outdoor air which is a weatherization concern as well as a radon/indoor air quality concern.
Note: sellers are not required to upgrade construction standards to current standards.

If the round duct is in fact an HVAC ducts, it should (must around here) the insulated. This falls under weatherization and also as you observed, causes condensation in unconditioned spaces below the house.

You are correct about the missing three screws.

HVAC installation practices requires proper support of the duct, not using electrical wires and structural members. Not home inspection issue however.

The rusted wingnut is from the sheet metal screw attaching the register boot to the duct above and is a result of condensation. Insulation would correct this. The wingnut is for a damper to control air flow. This will always happen because of the duct is below the dew point temperature of the crawlspace/basement when the air conditioner is running. It becomes a problem when this condensation in the rots the floor, contributes to mold growth, and insect infestation .

The air duct that is not screwed or taped is not adequately inserted into the adjoining duct. This will cause leakage into the crawlspace which causes the inside of the house to go into a negative air pressure which will pull all kinds of bad stuff through the building envelope. This and the return duct leakage can become problematic because of weatherization and indoor air quality concerns. This could be reported as “does not operate as intended” because air duct is intended not to leak.

Now, in reference to the electric wire touching the duct; I am going to have to disagree to some extent with Robert Young’s opinion about the duct getting high enough to melt electrical insulation. Robert is in Canada and can probably help you more than I can concerning standards there, and is an excellent resource to new inspectors such as yourself.

The duct could get hot, but it would have to be a catastrophic malfunction which would probably be burning the house down before two layers of electrical insulation was compromised. Electric and gas furnaces have high temperature safety controls to prevent such a condition. These furnaces have multiple controls to protect over temperature of the supply Plenum/heat exchanger. They are electric snap action safety devices around 120 to 140°F ranges and fusible links which are one time safety devices like a fuse. These are rated at higher temperatures than the electrical safety’s. So it is near impossable for for a safety failure this catastrophic to occur. There is the potential for vibration or sharp electrical duct to cut the insulation, causing a breaker trip I guess.

So the short of it is that your observations are well made but your documentation should reflect the extent of the concern to your client. Referring further investigation by someone else cost money that no one will appreciate, so I would point out my observations and let the client follow-up as they see fit. No mention of the house may burn down because electrical wire is touching the duct etc. I advise my clients of the “potential” for conditions such as these (never that they actually are occurring).

There is an opportunity here to up sell radon testing/weatherization testing services once you become a proficient home inspector. But it is my opinion issued work on your home inspection standards before you branch out into other fields (unless you are already qualified from a previous life).

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I appreciate the feedback, very well written and plump with information. Being able to observe and report accurately to the client is something I really want to work on because as you said, things cost money and people dont like that, so i do not want to go around scaring people.

Hopefully down the road i can add to my ancillary services to better serve my clients.


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