Construction forum - Extracting energy from the attic and outside?

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Extracting energy from the attic and outside?

2007-11-13, 8:25 pm

Hey Guys,

I am renting a one-story house that has an insulated attic space. The
house heating is not yet running because of some boiler tasks that need
attention. Today the temperature in the rooms below was 62 and the
temperature in the attic was 94. Outside the temperatire was about 65.
The insulation is chopped up bits - like fistfuls - of glass fibre. I
am thinking of using a fan to extract the warm air from the attic and
suck or blow it down through a HEPA filter and the attic access hatch.

Has anyone done this and, if so, I'd like to know the make/model of the
fan/filter unit? I am having trouble finding a fan/filter unit. Seems
that the filter is always the missing part. The attic hatch is 16"x25".

One wall of the house is facing south and it has two small bathroom
windows there - typical stupid construction to have two tiny windows
facing south and a far bigger area of glass facing north. Anyway, I
would like to know of a solar air heater that I could attach to that
window and have the warm air circulate into the house, or pumped in with
a small fan. I would not mind making the unit myself, if I had a proven
design. That side of the house is seldom used because it is basically a
yard with a 6' high fence about 10' away from the window.

Comments appreciated.

RF

hawgeye

2007-11-14, 9:25 am

"RF" <RF@Den.con> wrote ...
> Hey Guys,
>
> I am renting a one-story house that has an insulated attic space. The
> house heating is not yet running because of some boiler tasks that need
> attention. Today the temperature in the rooms below was 62 and the
> temperature in the attic was 94. Outside the temperatire was about 65. The
> insulation is chopped up bits - like fistfuls - of glass fibre. I am
> thinking of using a fan to extract the warm air from the attic and suck or
> blow it down through a HEPA filter and the attic access hatch.
>
> Has anyone done this and, if so, I'd like to know the make/model of the
> fan/filter unit? I am having trouble finding a fan/filter unit. Seems that
> the filter is always the missing part. The attic hatch is 16"x25".

First off, before you do anything you may want to get the owners permission.
Secondly, it sounds like the attic is poorly ventilated, which could become
a problem if you start creating a negitve pressure by sucking air out of it
with a fan.
Not to mention if that is loose insulation, chances are you'll be clogging
that hepa filter in no time.

> One wall of the house is facing south and it has two small bathroom
> windows there - typical stupid construction to have two tiny windows
> facing south and a far bigger area of glass facing north. Anyway, I would
> like to know of a solar air heater that I could attach to that window and
> have the warm air circulate into the house, or pumped in with a small fan.
> I would not mind making the unit myself, if I had a proven design. That
> side of the house is seldom used because it is basically a yard with a 6'
> high fence about 10' away from the window.
>
> Comments appreciated.

One word... heat-pump! Then again today's temps may have been a rare
occasion.
You didn't mention where you were, so anything you come up with may not be
worth the effort if it can only be used once in a while.
I applaud your efforts of using free heat but keep in mind this is a rental
property.

--
hawgeye ©

2007-11-14, 1:25 pm

hawgeye wrote:
> "RF" <RF@Den.con> wrote ...
>
> First off, before you do anything you may want to get the owners permission.

The installation I have in mind would simply sit in the hatch to the attic,
possibly with a few screws into the rafters and a few small plywood sheets
on top of the insulation near the hatch - no other construction.

> Secondly, it sounds like the attic is poorly ventilated, which could become
> a problem if you start creating a negitve pressure by sucking air out of it
> with a fan.

The attic has plenty of vents but when there is little or no wind, the
hot air accumulates
there. That's simply a law of nature :-)

> Not to mention if that is loose insulation, chances are you'll be clogging
> that hepa filter in no time.

I would build a vertical box around the opening of the hatch, so the air
intake
to it and the fan below it, would be about 18" or more above the top of
that intake
box and the insulation. I could even lay some plywood temporarily on top
of the
insulation out to, say 3' from the box. In strong winds, I would not
have the
fans running.

>
> One word... heat-pump! Then again today's temps may have been a rare
> occasion.

I doubt that air-air heat pumps could be very efficient. There has to be a
significant difference in the temperatures. That would require digging a
trench in the backyard.

> You didn't mention where you were, so anything you come up with may not be
> worth the effort if it can only be used once in a while.

I am about 60 miles north of San Francisco and about 20 miles in from
the Pacific coast.

What I am looking for is something that could be constructed in a day. I
don't mind
doing that much and it would be a good experience.

> I applaud your efforts of using free heat but keep in mind this is a rental
> property.

I like the challenge and it's in a good cause. There would be little
more damage than
there would be with hanging pictures on walls. I have been a DIYer since
I was able
to lift a hammer :-)

Yesterday I explored the attic some more and found that there is not a
scrap of insulation
on the ductwork.

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