How to check air/heat ducts?

Rkh

Member
My aunt has a 39yr old trailer & her heat bill & central air conditioning bill are outrageously high & was wondering if there's a way to check her but ductwork without taking off the insulation off?
 
At that age was it made before the government required certain energy standards in mobile homes? I've got one I use for storage with 2" walls that is an aluminum skin with 1" of insulation and 1/4" paneling inside,. When it's zero outside you don't want to hold your hand on an outside wall too long. Whats in the ceiling for insulation I have no idea but it couldn't be much.
 
Like Leroy said, trailers that old had very little insulation. As far as cleaning the ducts, you could get a sump pump discharge hose to use for a vacuum extension and try cleaning out the ducts. I wouldn't tear into the floor insulation unless I was pretty sure there's a problem. Covering the windows with plastic will help.
 
Amazon has endoscopes that are up to 33' long. They connect to a smartphone, and some say they have 1200p resolution. Pretty cheap prices. I remember when even a short endoscope would set you back several hundred.
 

A good shopvac and some semi rigid tubing to slide into the duct work is one method. The other is a high velocity blower to back flush the system. Some HVAC contractors have them.
 


Poking into the ducts will most likely destroy or damage them. Visual inspection from the outside would be much better.

As others have said, these homes have an r1.5 insulation, single pane windows, and loose heat very fast.

Skirting, and window treatment, door flashing and seal treatment will help also, but overall, it will loose a lot of heat.

Usually keeping the home at a modest 50-60 degrees overall and using a room heater to keep one room comfortable will probably be the best solution????

We spent 5 years traveling in our motorcoach and from the waist up, it was warm, from the waist down it was cold. Not a good winter dwelling while using electric heat. When we switched to propane, it would really take the chill off, but it ate propane like candy.
 
Back in the mid 90s I moved mobile homes all over the U.S. Most had a plastic SORT OF CLOTH THAT HELD THE INSULATION up and that stuff goes bad over the years or rats and mice eat holes in it then the insulation falls down so little to no insulation is around the ducting any more so the cost the heat and cool also goes up unless it is well skirted and the skirting well insulated. One can open up each floor vent and look in and see if the piping is still hooked up as it should be at each. Good idea to crawl under an have a look see
 
Rkh; In answer to your specific question, I'd say there is no practical way to check the condition of the ductwork without removing the insulation and inspecting it. Two days ago we paid just under $1500 to a company that does ductwork installation and repair to seal the ductwork under the part of our house which is above a crawl space. This is the original part of our house, and the part we spend most of our time in. It is about 1200 square feet.

Four young men spent seven hours removing the old duct insulation, fastening the joints of the metal ducts with sheet metal screws, applying mastic to all joints, and covering all ducts with R-13 fiberglass insulation secured with twine. (They also wrapped some water supply pipes with insulation, and replaced about 175 square feet of R-30 fiberglass insulation between the floor joists where I had pulled down the old insulation that had been damaged by rats a few years ago. Those parts of the job would have accounted for a small part of the time, but I've already taken the cost of them out of the figure I stated.)

We live in Olympia where prices are affected by our proximity to Seattle. If you don't live in the metro area of a large, overpriced city you might be able to adjust the price of such a job downward significantly. Also, you could adjust one way or the other for difference in square footage. I hope there's some information here that you can use.

Stan
 
I would have to agree with [b:8182fd71ab]sotxbill[/b:8182fd71ab].

40 year old duct work in a mobile home would be easily damage if you go poking it with objects.

Have you considered upgrading the unit to a DAOS (dedicated outdoor air system)? AC and heat all in one unit. It would be easy to run new duct work under the trailer and insulate it good. Plus a DAOS system is easily be removed and installed at another location should she decide to move or buy another home.

Paint the roof with something like Kool Seal.
 
I thought that the electric companies have a scope that they can aim at ducts while heat on and it will detect where heat lose is located. They can do the same thing with windows and doors.
 
Short of just a visual inspection, they can be checked with the "smoke" test.

I've never done it, but looks simple enough. Tape off all the registers and the plenum from the furnace. Tape the exhaust hose from a shop vac into one of the registers. Drop a couple of smoke bombs in the vacuum, turn it on and look for leaks.

The smoke bombs can be bought at HVAC supplies or online. They are odorless and safe.
 
I suppose the answer to your question would depend on what you mean by "check out".

I'm not a mobile home person, but I'm assuming that the ductwork is located under the floor (in non-conditioned space.) If it is leaking in non-conditioned space, it will create negative pressure in the conditioned space. Air will need to be drawn in from somewhere to make up for the air "leaked" to the outside.

I had a situation a couple of years ago where the electric resistance heat for my heat pump started kicking in at temperatures 15 degrees higher than I had experienced in prior years. One of the things I did to trouble shoot my issue was to borrow an infrared non-contact thermometer to "play with". (I didn't know the first thing about using one.) When I pointed it at the bathroom exhaust fans, the temperature read much colder than the surrounding ceilings. This was a sure sign that "make-up" air was being pulled in from the outside. A later inspection of my HVAC system showed that I had a major leak in my attic. (The supply plenum was a box make of insulating board that was taped at the joints. The tape holding the top on the box had failed on three of the four edges. When the blower kicked on, the top of the plenum just hinged open like a door----dumping a large portion of the heated air into the attic.)


If the mobile home has gas or oil fuel for the furnace and/or water heater, a major duct leak could cause some health/safety problems. The "make-up" air may be drawn from the furnace and/or water heater flues.


Others have stated that older mobile homes are not likely to be well insulated. Many mobile homes also seem to have bottom of the line (low efficiency) HVAC equipment. This can contribute to high energy costs.
 
As stated, old trailers typically have little insulation and very light construction, made worse by age. One quick place you can check without full tear-down is the elbows between the main ducts and the floor registers. Many trailers, especially old, relatively narrow ones, are set up with just a single run of ducting down through the rough center of the floor and elbows leading up from there to the floor registers. These are often made from leftover scraps of ducting just jammed into the main duct, and leak like sieves, putting a large portion of their air into the space under the trailer where it does little good. In my old trailer I went through each duct, pulled the register (usually just a couple screws, and often not attached at all, just pressed into place) and with a mirror, a bright light, and with my hands (careful--there's often sharp edges) examined each one and used aluminum tape (sometimes called silver tape, and it's NOT duct tape--this is the purpose-made metal tape with VERY aggressive adhesive made for just this use) to seal each one. It made a TREMENDOUS difference in the amount of heat that came through the ducts, paying for itself easily within a month or two, and should be done regardless of whatever else you do. Link below is the tape I'm talking about at Amazon--the same basic thing's available at any good hardware store in many sizes, brands, etc., I'm just including this as an example.
silver tape
 

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