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Do I really need a solar collector to heat my home?

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Posted by pautrey2 on November 29, 2008, 6:17 am
Do I really need a solar collector to heat my home, or can I get just
as much heat by adding a south-facing window?

 Rowan Wilkinson
Milwaukee, Wisconsin

Windows and solar hot-air collectors are about equal in collection
capability. I think the choice boils down to which works best for your
situation. To me, these are the pros and cons.

Window Pros:

 Collect heat and provide daylight.


 Nice bright interior.

 With good thermal mass (material that absorbs and maintains heat)=
the house, they can carry some heat into the evening.

Window Cons:

 High heat loss at night and on cloudy days (can be somewhat overc=
with thermal shades).

 Can be undesirable in some situations because of glare or loss of

 Can lead to overheating unless you have overhangs for summer and =
house with adequate thermal mass to absorb the heat.

 To be effective, your south wall has to have a good view of the
south sky.

 You need a floor plan in which it makes sense to have windows in =
south wall.

 Its harder to distribute the heat into the parts of the =
house where
you want it.

Thats a fairly large list of cons, but solving these problems is w=
passive solar house design is all about. If you do it right, the
windows both collect heat and make the house a bright and pleasant
place to be. In a retrofit situation, you just have to be lucky that
you can place the windows where you need them for passive solar.

Solar Hot-Air Collector Pros:

 More flexible in locationsouth roof, s=
outh wall, even detached
from houseand easier to find a location with goo=
d sun.

 Can move the heat from the collector to where you want it more
easily than with windows.

 It is possible to store heat for later use (at the cost of more

 No night heat loss problem.

 Solar Hot-Air Collector Cons:

 You lose the daylight and the views.

 Often have controls and fans that must be maintained.

 Typically they dont look as good as windows.

Its not really an either/or situationyo=
u can (and should) use both
on the same house. You can even mix them on the same south wall. I did
not include cost as a pro or con for either option, since it can vary
so much depending on how you go about it.


Posted by Eeyore on November 29, 2008, 2:30 pm

pautrey2 wrote:

Can you get low-emissivity glass in the USA ?

I believe it was originally a Pilkington UK patent.


Posted by Tim Jackson on November 29, 2008, 3:49 pm
 Eeyore wrote:

I've been experimenting with replacing my Victorian timber-panel
interior shutters with double-skinned fibre-filled shutters as a cheap
alternative to fitting double glazing.  Using a simple DIY frame of
2"x1" timber clad in 6mm MDF, with glass-wool fill, over single glazing,
I'm measuring a metric U-value (conductance) of about 1.1 as opposed to
the latest, best and most expensive double glazing rated at 1.5.

I also get a perceived noise reduction at least comparable to and
probably better than double glazing I have had fitted in other rooms at
considerably greater cost.

Of course on the downside you can't get sunlight at the same time, and
you have to get up and shut the shutters when it goes dark.  But then I
am at 54N, so sunlight is at best brief in the season when we most need

Tim Jackson

Posted by nick hull on November 30, 2008, 2:01 pm

I've been using thermal shutters at night for 25 years made from 1"
thick styrofoam cut to a snug fit.  Really keeps the heat in at night
and my wife (who sits at her computer next to a picture window) comments
that the room feels instantly warmer when she puts the shutter up at

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/
** Posted from http://www.teranews.com  **

Posted by Tim Jackson on November 30, 2008, 3:15 pm
 nick hull wrote:

I've a friend in the northern US who got me going on this.  She sticks
Velcro down the sides of her window frame and cuts pieces of quilt to
fit for long cold winter nights and in unused rooms.  (A 15-tog
bed-quilt has a U-value of .67 - twice as good as double glazing.)


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