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Old 01-26-11, 10:51 AM   #7
AC_Hacker
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Default Turbo Mini-Split...

Quote:
Originally Posted by cholcombe View Post
...to place the outside of unit of a heat pump in your unheated attic? I figure you're losing heat through there anyways so maybe you'd be able to recapture some of it...
Thought I'd weigh in on this one...

Quote:
Originally Posted by Piwoslaw View Post
Once the heat pump starts sucking heat from the attic, it will get cold in there, colder than outside, so in effect it won't be more efficient than placing it outside.
This could be worked to your advantage... If you had no insulation between the roof and the inside of the attic, AND had some really excellent insulation in the attic floor (like maybe R-60 ridgid foam + radiant reflector on top), it would be different. Then your heat pump would greatly benefit from the trapped warmth in the attic (in this case you would want a black roof). But still, the exhaust from the mini-split would be best vented outside.

In the summer, if you could bring in fresh air straight into the mini-split and still exhaust the minisplit to the outside, it would work out.

But Xringer is right, in the winter, the minisplit put out huge quantities of very cold air. If you had your mini-split in the mud-room, you'd best change its name to 'The Deep Freeze' (in all seriousness).


Locally there is a house called 'The Rose House' that has PV on the roof and channels the hot air that is coming off the back of the PV panels to feed the input of the mini-split. It improves the efficiency of the mini-split and the PV panels.

-AC_Hacker
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