Attic heat exchanger?
 

I've been contemplating methods of obtaining heat from
the attic for heating the house during appropriate times
of the year. One idea I have is to put a ducted fan in
the attic to blow the warm/hot air into the garage as an
initial experiment. I can heat the garage to determine
the feasibility of the concept.

I'm also thinking that a reversible ventilator would be
in order in that it could double as a way to vent hot
air from the garage into the attic and out through the
roof vents during hot weather. This would even cool the
attic somewhat and help the A/C load on the main part
of the house.

Anyone have any thougts?

Attic heat exchanger?
 

buffalo ny: garage air due to car exhaust concerns is usually required
to be isolated from the home. i would put money into insulating the
attic to retain the home's heat.
for your complete answers:
http://www.buildingscience.com/resources/


Everett M. Greene wrote:
I've been contemplating methods of obtaining heat from
the attic for heating the house during appropriate times
of the year. One idea I have is to put a ducted fan in
the attic to blow the warm/hot air into the garage as an
initial experiment. I can heat the garage to determine
the feasibility of the concept.

I'm also thinking that a reversible ventilator would be
in order in that it could double as a way to vent hot
air from the garage into the attic and out through the
roof vents during hot weather. This would even cool the
attic somewhat and help the A/C load on the main part
of the house.

Anyone have any thougts?

Attic heat exchanger?
 

Everett M. Greene wrote:

I've been contemplating methods of obtaining heat from the attic
for heating the house during appropriate times of the year.
One idea I have is to put a ducted fan in the attic to blow
the warm/hot air into the garage as an initial experiment...

Good idea. For more heat, you might replace a south roof with transparent
polycarbonate Dynaglas greenhouse roofing material, which comes in 4'x12'
corrugated sheets and costs about $1/ft^2 and lasts about 20 years.

You'd also want a return air path and one-way dampers to avoid letting
warm air go up into the attic at night. Return air might go up through
a ceiling register with a box above it and some heavy plastic film hanging
over the screened south wall of the box for a damper. With the transparent
roof, the box could also act as a skylight. Supply air could come from
a fan below the ceiling that pulls attic air down through a tall duct,
with light plastic film hanging over the fan outlet.

I'm also thinking that a reversible ventilator would be in order in that
it could double as a way to vent hot air from the garage into the attic
and out through the roof vents during hot weather.

That's easier, since warm air rises. You might block the roof vents and add
gable vents with doors that open in summertime and close in wintertime.

Nick

Attic heat exchanger?
 

My brother did something like this and it worked like a champ.

The house was a ranch with attic access from the garage. He just
placed a box fan in the opening and had the fan blow downwards into the
garage. We're in a 8800 dd climate and he found that it worked best in
the spring / fall.

This was done mainly as an experiment, but it did work and I recall
that quite a lot of heat was available. If one wanted to do it
"right", I would envision a system with a thermostatic
switch/thermostat, ducting to pull the heat from the top of attic, to
floor level (heat rises), possibly a filter and some kind of high temp
cutoff (fire safety). Plus you'd need to think of some kind of return
duct as just blowing heat from the attic would result in some
pressurization of the house, that air needs to go somewhere...

I'd encourage some experimentation first. (cheap fans and some flexy
duct snaking through the house).

Good luck.

Attic heat exchanger?
 

writes:

Thanks to you and the others who replied.

My brother did something like this and it worked like a champ.

The house was a ranch with attic access from the garage. He just
placed a box fan in the opening and had the fan blow downwards into the
garage. We're in a 8800 dd climate and he found that it worked best in
the spring / fall.

This was done mainly as an experiment, but it did work and I recall
that quite a lot of heat was available. If one wanted to do it
"right", I would envision a system with a thermostatic
switch/thermostat, ducting to pull the heat from the top of attic, to
floor level (heat rises), possibly a filter and some kind of high temp
cutoff (fire safety). Plus you'd need to think of some kind of return
duct as just blowing heat from the attic would result in some
pressurization of the house, that air needs to go somewhere...

I'd encourage some experimentation first. (cheap fans and some flexy
duct snaking through the house).

Any suggestions for a source and size for ducted fans?


From: "buffalobill"

buffalo ny: garage air due to car exhaust concerns is usually required
to be isolated from the home. i would put money into insulating the
attic to retain the home's heat.

The garage is already insulated.

for your complete answers: http://www.buildingscience.com/resources/

I'll look into this.

From:

Good idea. For more heat, you might replace a south roof with transparent
polycarbonate Dynaglas greenhouse roofing material, which comes in 4'x12'
corrugated sheets and costs about $1/ft^2 and lasts about 20 years.

I live in the Mojave Desert. I don't need any more heat,
especially in July and August :-)

Attic heat exchanger?
 

Any suggestions for a source and size for ducted fans?


Well, there's this place:
http://www.espenergy.com/in_line_duct_fan.htm

I know nothing about the company at all, but just did a quick search
for "in-line duct booster" and they showed up. Looks like they also
sell thermostats and dampers too. A six inch duct booster is ~$27. I
don't know much about ducted fans, but I think they don't like back
pressure, therefore short straight runs with few restrictions may be
best. AFA size 6" or 8" I'd guess.

My local Menards (midwest version of HD) has booster fans too. You
may want to check around.

Attic heat exchanger?
 

On Tue, 2 Jan 2007 22:39:37 PST, (Everett M.
Greene) wrote:

I've been contemplating methods of obtaining heat from
the attic for heating the house during appropriate times
of the year. One idea I have is to put a ducted fan in
the attic to blow the warm/hot air into the garage as an
initial experiment. I can heat the garage to determine
the feasibility of the concept.

I'm also thinking that a reversible ventilator would be
in order in that it could double as a way to vent hot
air from the garage into the attic and out through the
roof vents during hot weather. This would even cool the
attic somewhat and help the A/C load on the main part
of the house.

Anyone have any thougts?

IMHO:

IN the winter time, if you have a properly ventulated attic space you
should have a 'cold' roof. So effort applied for yoru return can be
minimal. I suggest if you want to try to utilize solar heat, cut out
the middle step and get professionallly done heat exchangers installed
on your roof.

Another idea that came to mind, if you were pumping cold fluid into
tubes in your attic, you migght be creating a condensation problem on
the tubes that has to be dealt with.

Not a attic, or solar heating expert, just guessing here...

tom @ www.MedJobSite.com

Attic heat exchanger?
 

mrfixit341 had written this in response to
http://www.thestuccocompany.com/main...er-181411-.htm
:
I had the same idea not long ago.A man could run some large flexible duct
from the attic and tie it into the air intake.Of course put a shutoff on
it for summer.You would also have to put a temp sensor in the attic and
have a programmable thermostat with emergency heat setting to run the fan
or some kind of relay or 2 thermostats.If the temp in the attis was hot
enough on the heat setting it would kick on the fan and heat the house.Or
have a seperate fan and thermostat to run it separately.I think you get
the idea.Thanks Mark Whitney.Lets make a system and sell it$$$

-------------------------------------
wrote:




My brother did something like this and it worked like a champ.

The house was a ranch with attic access from the garage. He just
placed a box fan in the opening and had the fan blow downwards into the
garage. We're in a 8800 dd climate and he found that it worked best in
the spring / fall.

This was done mainly as an experiment, but it did work and I recall
that quite a lot of heat was available. If one wanted to do it
"right", I would envision a system with a thermostatic
switch/thermostat, ducting to pull the heat from the top of attic, to
floor level (heat rises), possibly a filter and some kind of high temp
cutoff (fire safety). Plus you'd need to think of some kind of return
duct as just blowing heat from the attic would result in some
pressurization of the house, that air needs to go somewhere...

I'd encourage some experimentation first. (cheap fans and some flexy
duct snaking through the house).

Good luck.






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