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Are there any red flags for covering High Velocity Air Conditioner with blown-in insulation?

We have a high velocity (spacepak air conditioning) in our attic. We currently have about 4-5 inches of insulation on there. The local gas company is offering a rebate if we add in 10-12 inches of blown-in insulation so we can get a rating of R49. If we do this the entire truck line and supply lines will be covered in insulation and they we submerged entirely in insulation. The contractor we are using says it should help our air conditioner work better. I do agree but I have concerns about covering the parts in that much insulation. Won't it be harder to repair? We are currently planning to mark (with flags) where the supply lines meet the truck and go down into the house however, I am still concerned. Does anyone have any experience with something like this? I know a few supply lines will need to be repaired in the future and our handler is older 1990's. We already had to replace our truck line and a few supply lines that were crushed when we bought the house. The contractor I am working with is familiar with spacepak but has never heard of having to replace trunk or supply lines so he kind of thinks I am crazy when it comes to my concerns. Any words of wisdom would be greatly appreciated.


  • Jamie Hall
    Jamie Hall Member Posts: 22,934
    There shouldn't be a problem covering the air handling ductwork, although I would examine it pretty closely to make sure that all the joints are properly sealed -- particularly any return lines. Your idea of putting in markers where there are connections or grilles is a very good one.

    That said. Do NOT bury any of the electrical lines, nor any mechanical equipment, nor any lines containing refrigerant or anything of that sort. Also don't bury electrical lines connected to other things -- overhead lights, or feeders to outlets etc. And don't bury any overhead lights or recessed fixtures, unless you are absolutely sure that they are rated for that. Most aren't.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 15,335
    I would make any ductwork repairs needed before insulating. I would suggest enclosing any duct runs likely to be walked on (if any) with a wood enclosure if they will be concealed by the insulation.

    @Jamie Hall is correct that some recessed light fixtures are not rated to be buried in insulation.
    JUGHNE Member Posts: 11,021
    You are lucky to have an insulation contractor aware of your duct work. Many will not worry about walking on anything, they know they will be gone before you realize there is a problem.

    I would build a wood bridge over any duct that may become a walkway now and in the future.
    If I were asked to repair attic ductwork that just 2 weeks ago was not buried in the insulation.....I would be too busy or certainly charge accordingly.

    As for recessed lights. If you take out the bulb and trim the label inside will tell you if they are IC type, that is insulation coverage. If so then you are limited on bulb size installed. I would usually wrap IC cans with fiberglass insulation so the dust of blown in would not seep thru the housing. ( Plus not all blown in insulation is as fire resistant as fiberglass)

    If you have the TC type, this requires 3" separation from insulation......these cans usually let you install a higher wattage bulb. They might be the same construction as the IC, but the label inside the can dictates the max bulb size.
    I have built large wood boxes to sit over the TC type where we needed more wattage. If it over heats inside the box (unlikely) the thermal overload will trip and shut the bulb down.
  • BobC
    BobC Member Posts: 5,473
    Using incandescent bulbs in recessed fixtures is a problem.

    Replacing the bulbs of recessed cans with LED lamps reduces the temperature dramatically especially if you can find the cloud type, they separate the LED's from the driver and run much cooler then traditional LED lamps. I have a couple of them and they probably run at 90F or so.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • adam061712
    adam061712 Member Posts: 11
    Thanks for everyones comments. This is very helpful information. The insulation project is part of a bigger Home Energy Audit. We had the attic sealed and as part of that. Included as part of it they box out the can lights as well as the house fan. Currently, my understanding is that none of the mechanical tied to the air handler will be covered in insulation. We are concerned about the return. There is only one air return for our system and it is old so we were going to specifically make sure they don't fill the insulation to high around that. As for the electrical up there most of it is up high. Now that you all mentioned that I am going to make sure that none of the electrical is covered. I am also going to check the refrigerant line.

    Any other words of wisdom would be greatly appreciated. Also if anyone has worked/seen a spacepak in a lot of insulation (12 inches +) I would love to hear what your experience was with working on it. Also if you know of people that added this much insulation and were extremely happy with the efficiency/inefficiency of the system as a result I would love to hear that too. The contractor is convinced this insulation will help the system work better and more efficiently. I never thought the system was inefficient to begin with. My electric bills have always been very reasonable in the summer time.
  • unclejohn
    unclejohn Member Posts: 1,833
    All spacepac replacement units will require a larger trunk line then what you have now. There are no more 8" trunks.