Posted by Neo on April 6, 2010, 1:03 am
> > Neo wrote:
> > > which would you do first?
> > > 1. upgrade conventional vinyl siding to insulated vinyl siding (adds
> > > an additional 4.0 R-Factor) on a frame house.
> > > 2. upgrade 6 dual pane conventional windows and a patio door(approx. .
> > > 60 U-Factor) to energy star argon filled dual/triple pane windows
> > > (about .25 U-Factor)
> > Are the walls already insulated? How well?
> It's a 20 year old three level townhouse (middle unit, 18 feet wide,
> 33 feet deep, 500 sq ft each level)
> The Attic ( about 12 inch fiberglass batting ) = R38
> The Wall (1' styrofoam sheathing + about 6" fiberglass batting) = R4
> + R19 = R23
> Main Floor Joist ( 8 " fiberglass batting) = R23
> 6 std + 2 mini windows ( 2 pane glass separated by 3/8 inch metal
> spacer, vinyle frame, estimated U-Factor =0.6 ) = ? R3
> 2 Patio Screen doors ( 2 pane w/ UV coating separated by 3/4 inch
> metal spacer, alum frame- spacer) = ?R??
> 1 metal insulated core door = R11
> The advise I got from my neighbor was that the biggest energy saving
> project would be to replace the 2 patio screen door.
-
I talked to a window salesman about upgrading my windows (8) and patio
doors(2) with
double pane, UV film, argon filled, insulated reinforced vinyl frame
windows manufactured by
Camelot Windows ( Model=Crusader, U factor =.27, SHGF= .26,
Condensation resistance =61)
the estimated cost for the upgrade was $4000. The townhouse is in
the
MD suburbs of Washington DC and the electricity cost about (with a
contract
from Clean Current's Wind Turbine electricity) is 15 cents/kwh.
My rough estimate is that about 50 to 300 kwH/month between June and
August is used cool the townhouse and between 50 to 800 kwH/month
between
September and May is used to heat the townhouse. I believe that about
80%
of my electrical usage in my all electric home is used for heating and
cooling;
this amounts to about 4400 kwh/year. My guess is that the improved
windows
and patio doors would increase the townhouse energy efficiency by 50%
because
the windows/patio doors would go from about a U factor of .6 to .27.
Thus
my estimated energy saving would be approximatedl 2200 kwh/year
a savings of $30 year. However because the cost of the new windows
would
be $4000 - it would take 43 years to break even. Even if energy
cost
quadrupled to 60 cents/kwh -- with a savings of $320/year it would
take
11 years to reach the break even point. sigh.,...
.
Posted by vaughn on April 6, 2010, 1:19 am
>However because the cost of the new windows would be $4000 - it would take 43
>years to break even. Even if energy
>cost quadrupled to 60 cents/kwh -- with a savings of $320/year it would take
>11 years to reach the break even point. sigh.,...
Actually it would take much longer than 43 years because you failed to consider
cost of capital. Also your projected energy savings seems so high that I wonder
if it is realistic. On the other hand, it may increase the value of the unit,
but probably not by $4,000
There are considerations beyond simple energy payback. We actualy paid much
more that $4,000 to replace the 40 year-old windows in our house, and I
condiser it money well spent. Besides, the energy savings, the house is much
more comfortable, quieter, and even cleaner. Since we live in hurricane
country, the (impact type) windows give us significant hurricane protection and
qualify us for an insurance discount. That said, I never expect them to pay for
themselves!
Vaughn
.
Posted by Guido on April 6, 2010, 10:23 am
vaughn wrote:
> There are considerations beyond simple energy payback. We actualy paid much
> more that $4,000 to replace the 40 year-old windows in our house, and I
> consider it money well spent. Besides, the energy savings, the house is much
> more comfortable, quieter, and even cleaner. Since we live in hurricane
> country, the (impact type) windows give us significant hurricane protection
and
> qualify us for an insurance discount. That said, I never expect them to pay
for
> themselves!
That depends on how you value comfort and sense of security, eh?
Like you said, "money well spent"! ;-)
Posted by Guido on April 6, 2010, 10:18 am
Neo wrote:
> Thus my estimated energy saving would be approximatedl 2200 kwh/year
> a savings of $30 year. However because the cost of the new windows
> would be $4000 - it would take 43 years to break even. Even if energy
> cost quadrupled to 60 cents/kwh -- with a savings of $320/year it would
> take 11 years to reach the break even point. sigh.,...
I wonder what you'd save if you put the $4,000 into PV cells on the
roof to generate your own electricity?
Posted by Josepi on April 6, 2010, 3:37 pm
It would cost you $4K at 5% interest (not invested or mortgage payments) =
700 per annum.
You panels may generate that much but not likely.
Neo wrote:
> Thus my estimated energy saving would be approximatedl 2200 kwh/year
> a savings of $30 year. However because the cost of the new windows
> would be $4000 - it would take 43 years to break even. Even if energy
> cost quadrupled to 60 cents/kwh -- with a savings of $320/year it would
> take 11 years to reach the break even point. sigh.,...
I wonder what you'd save if you put the $4,000 into PV cells on the
roof to generate your own electricity?
> > > which would you do first?
> > > 1. upgrade conventional vinyl siding to insulated vinyl siding (adds
> > > an additional 4.0 R-Factor) on a frame house.
> > > 2. upgrade 6 dual pane conventional windows and a patio door(approx. .
> > > 60 U-Factor) to energy star argon filled dual/triple pane windows
> > > (about .25 U-Factor)
> > Are the walls already insulated? How well?
> It's a 20 year old three level townhouse (middle unit, 18 feet wide,
> 33 feet deep, 500 sq ft each level)
> The Attic ( about 12 inch fiberglass batting ) = R38
> The Wall (1' styrofoam sheathing + about 6" fiberglass batting) = R4
> + R19 = R23
> Main Floor Joist ( 8 " fiberglass batting) = R23
> 6 std + 2 mini windows ( 2 pane glass separated by 3/8 inch metal
> spacer, vinyle frame, estimated U-Factor =0.6 ) = ? R3
> 2 Patio Screen doors ( 2 pane w/ UV coating separated by 3/4 inch
> metal spacer, alum frame- spacer) = ?R??
> 1 metal insulated core door = R11
> The advise I got from my neighbor was that the biggest energy saving
> project would be to replace the 2 patio screen door.
-