Heat hoses in attic.

[CraigStu]

The heat pump in my 'garage' is in the attic. Typical blown in insulation on the attic floor and plenty thick. I have always wondered about the efficiency of putting it there vs in the workspace but I guess you do gain more work space w/ it in the attic. I happened to be standing under a ceiling heat outlet right when the fan started. It blew cold air for 5-15 seconds and then it got warm. So got me thinking about insulating the attic unit and all the hoses. The hoses are the insulated variety. Feels like a 6 inch hose wrapped w/ 2 inch insulation. They are hung w/ fabric straps from the trusses. I was thinking get a couple bags of rockwool batts to make a wrap for the unit. Also thinking lay the hoses down on the existing insulation and forming bats over them. I just don't see how it is good to have the entire system sitting in what has to be close to the outside temp w/o attempting to insulate them better? Your thoughts please.

 

[4x4Pete]

Will servicing the air handler become a problem with it covered in insulation? The air in the air handler and ducting will still get cold in comparison to heated air. Insulation doesn't prevent heat migration. It only slows it down. Longish off cycles will have the air become cooled in the ducts and air handler, and you will see little to no benefit. Insulating the attic and making it part of the heated area which the ducts and air handler would then be inside of, would make the biggest difference.

 

[frankd]

What's the heat source? We had a similar issue in our home but our heat is run through the central air conditioning ducts. There's a heating coil that used hot water from a gas fired boiler. The solution for was to add an aquastat on the water line near the air handler- which would prevent the fan from kicking on until the water reached a certain temperature.
I was told that its always going to blow cold air for a little while because you have cold air sitting in the vents when the system isn't on.

 

[jar944]

Hvac outside of the conditioned space is extremely common (fast, cheap, easy) and very inefficient.

The solution is to insulate the roof deck, not wrap the ducts and air handler. Burying it in insulation will just cause more problems with condensation and rot.

 

[CraigStu]

Sounds like my idea won't work real well. I know that some will heat/cool the attic but to me that would be a huge increase in heated/cooled volume which I think would overcome any savings I might get from the duct hose not being in ambient temp. And it would require a whole different insulation technique than is in the attic now. Oh well, it was just a thought.