Posted by ransley on March 23, 2010, 1:14 am
No vinyl siding adds R value itself and one inch of the pink or blue
foamboard is R 5", the white is R4" and if it has gaps as in its an
isert in the siding the R value is near Zero since you have openings
at each seam, are you sure you are being Pitched 1" foam. Either way
Low EArgon windows will be better and so will insulating the attic to
a high standard do more for your buck.
Posted by Bob F on March 23, 2010, 1:30 am
Are the walls already insulated? How well?
Posted by Neo on March 27, 2010, 3:18 am
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
would be to replace the 2 patio screen door.
Posted by daestrom on March 27, 2010, 12:31 pm
With three stories and only fiberglass batts for attic insulation, it
might be worth an afternoon to spend up in your attic.
I found that pulling back insulation above places like bathroom fans,
hall light fixtures and where ever wiring came up from a wall, the
insulation in my attic was dirty. This indicates that air was rising up
through the holes that weren't properly sealed.
A three level house can develop some fairly good 'chimney draft' and
literally pull the warm air from your conditioned space up through small
cracks/holes in the ceiling of the top floor into the attic.
When I found my problem, an afternoon with caulking gun and can of
expandable foam made quite a difference for me (I'm only in a two story
house). Then ditto down in the basement looking for cracks/leaks that
let cold air in at the bottom of the house.
I don't recall where you're at, but R38 could easily be improved upon in
the attic. Just be sure to lay new batts/roll cross-wise from the first
to help minimize gaps.
As for patio doors, double pane isn't too bad already. Check for
drafts/leaks around the doors and consider just heavy drapes at night.
Posted by Jim Wilkins on March 28, 2010, 1:49 pm
I have a standard 1970 development type house and upgraded the
insulation mostly by making insert panels that fit into the trim
around the windows and patio double door.
The window inserts are rectangles made of 3/4" x 5/4" yellow pine with
glued morticed corners, cut 1/4" smaller than the inside trim opening.
They were stained to match the windows, then covered on both sides
with clear polyester film, with 3/16" foam weatherstripping around the
outside so they press in like corks.
The door has a hinged double frame stiffened by horizontal
crosspieces, like a theatre flat.
but with dowelled joints instead of plywood keystones and corner
blocks. The upper part is clear film, the lower panelled to match the
walls and insulated with styrofoam, like the adjacent north wall.
I dowelled it because the vertical rails were too long and awkward to
slot on the table saw. You could do the same for the windows if you
find stiffer mortice and tenon joints too difficult.
I also added attic insulation and improved the weatherstripping on the
doors, but the window inserts make the biggest difference, so much
that I can soon tell by feel if the wind has blown one loose in a
closed spare bedroom.
Heat loss is about 2-3% of the difference between in and out per hour,
maybe 5 degrees F overnight with the heat off. There is still enough
air exchange that cooking smells go away in a few hours. Indoor
humidity stays around 50% in midwinter, that's what I used to decide
to stop improving the airtightness upstairs. I did almost nothing in
the basement because the fire needs air. Like a hot air balloon the
heat stays in if it can't escape upward.