Crawl space duct insulation

[Raisedonadeere]

Overheard my son mention recently widowed mother in law suffering with high lectricity bills and over 85 degrees in house on peak days. Had a look and saw one of thos situations that could destroy all respect for the Hvac guys that installed the ductwork and the later ones that serviced it in response to her calls for help. Long story to make the case against the HVAC people, but it is not pretty. This lady is one of the kindest most community oriented people you would ever have as a customer but perhaps it has something to do with deceased husbands somewhat abusive ways. Just trying to imagine how someone could do this kind of work without a grudge to motivate it.

Any way my son and I have set out to rehang the ducts, 8” metal runs that fell down, and my question for here is what is a good economical way to insulate them. Her crawl space is actually muddy under the ducts from the condensate dripping on these 90+ percent humidity days of late.

There is just adequate space to work so we need economical that works vs expensive but convenient. Is there a cheap plastic coated insulation of some sort that is suitable for ventilated crawl space? Other tricks of the trade? Her 2.5 ton unit is working its heart out and getting the blame for all this. We are going to do a generous mastic sealing of all the joints, some of which the elbo was just laying over the hole with no sign of attempt to cinch.

I can’t stand to see all the poor systems that I see when I visit homes but this lady needs the help because of finances. We are footing the bill and doing the labor as soon as we can get a plan together.

 

[HotRodBoater]

I don't know what part of the country you're in, but I've been doing a lot of research lately. Down here in the hot and very humid South, the current trend is to seal and insulate both crawl spaces and attics. The "experts" are saying this is the smart thing to do and ventilating these areas (in the South) is old outdated way of thinking. Basically the air conditioner and duct work will be in a part of the "conditioned" area and therefore leaky duct work won't be leaking to the outside. I'm not sure if this info is helpful to you or not

 

[JackDiddly]

Not sure that it would be "cheap" but you can get insulation sleeves for round duct that slide over the pipe. It would require you to disconnect one end of the duct run and slide the sleeves on over the duct. Local codes would dictate what R-value your insulation should be but likely not less than R-8.

 

[Raisedonadeere]

Not sure that it would be "cheap" but you can get insulation sleeves for round duct that slide over the pipe. It would require you to disconnect one end of the duct run and slide the sleeves on over the duct. Local codes would dictate what R-value your insulation should be but likely not less than R-8.

Hotrodboater if you know of any good resources for information on how to retrofit a crawl space to sealed insulated space I would appreciate a reference or two to get started on my research. I want to aim that way on my own house although it has tight sealed duct work. I live in KY but high humidity is the norm for summers. Just moved here from ALABAMA and the humidity makes for much more heat distress and challenges to good air conditioning than northern al

Thanks JackDiddly, those sleeves will be the best trick for this situation. No problem with disconnecting the ducts. They are all on the verge of falling out anyway I was just hoping for something cheaper, stuff was over $2/ft so this project would hit me in the wallet as well as my time. Won’t hurt me. Just don’t get as speedy on other people’s problems as my own

 

[NUTTSGT]

I've wrapped some of my ducts with Reflectix, foil faced bubble wrap, in my basement. I sealed the overlapped edges with foil tape.

While I don't believe their claims of R-values, I believe that they are based on a recipe of air gaps and layers of their products.

 

[stm317]

Hotrodboater if you know of any good resources for information on how to retrofit a crawl space to sealed insulated space I would appreciate a reference or two to get started on my research. I want to aim that way on my own house although it has tight sealed duct work. I live in KY but high humidity is the norm for summers. Just moved here from ALABAMA and the humidity makes for much more heat distress and challenges to good air conditioning than northern al

Here's a thread from a few months ago about crawl space encapsulation. It's got some good links for the concepts behind encapsulation as well as a reputable DIY website.
https://www.garagejournal.com/forum/showthread.php?t=384734&page=3

 

[yeldogt]

Getting someone to evaluate the crawl space would be my first move. Get a couple estimates ... it's impossible to tell you what to do with the information available.

Venting crawls and attics is outdated --- and was illogical for conditioned building ... vented roofs don't make any sense in most climates and are only a response to poor building practices .. there is always a better way.

If you leave the space open and tighten up the buildings ductwork -- you run the risk of actually making it work and lowering the floor above under the dew point .. that will have all that moisture condense on the underside of the floor. So what do people do? they insulate the floor.

The answer is to close up the vents and condition the crawl space -- problem solved