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INSULATION INSPECTION & IMPROVEMENT
ACOUSTICAL SEALANT CHOICES
AIR LEAK MINIMIZATION
ASBESTOS IDENTIFICATION IN BUILDINGS
BASEMENT CEILING VAPOR BARRIER
BASEMENT HEAT LOSS
BUCKLED FOUNDATIONS due to INSULATION?
CATHEDRAL CEILING INSULATION
CATHEDRAL CEILING VENTILATION
CEILINGS, DROP or SUSPENDED PANEL
DEW POINT TABLE - CONDENSATION POINT
DUCT INSULATION, ASBESTOS PAPER
FIBERGLASS PARTICLE CONTAMINATION
Fiberboard Insulation Sheathing Mold
FIBERGLASS INSULATION MOLD
FIREPROOFING ASBESTOS SPRAY-ON
FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FRAMING METAL STUD PERFORMANCE
FREEZE-PROOF A BUILDING
HEAT LOSS in BUILDINGS
HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS R U & K VALUE CALCULATION
HOUSEWRAP AIR & VAPOR BARRIERS
HOUSE DOCTOR, how-to be
HUMIDITY LEVEL TARGET
ROOF ICE DAM LEAKS
INSULATION AIR & HEAT LEAKS
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INSULATION FACT SHEET- DOE
INSULATION INSPECTION & IMPROVEMENT
INSULATION R-Values & Properties
LEED GREEN BUILDING CERTIFICATION
LOG HOME ENERGY EFFICIENCY
MOLD in FOAM INSULATION, RESISTANCE
MOISTURE CONTROL in BUILDINGS
NOISE / SOUND DIAGNOSIS & CURE
RIGID FOAM USE INDOORS
SHEATHING, FOIL FACED - VENTS
SLAB INSULATION, PASSIVE SOLAR
STAINS on & in BUILDINGS, CAUSES & CURES
STRAW BALE CONSTRUCTION
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
SWEATING (CONDENSATION) on PIPES, TANKS
Thermal Expansion Cracking of Brick
THERMAL IMAGING, THERMOGRAPHY
THERMAL MASS in BUILDINGS
THERMAL TRACKING Indicates Heat Loss
TRUSS UPLIFT, ROOF
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
WALL CONSTRUCTION BARRIER vs CAVITY
WIND WASHING INSULATION At EAVES
WINTERIZE A BUILDING
How to insulate windows from the inside: this article describes options for adding insulation on the indoor side of windows in an older home. Insulating panels, solar shades, or interior storms can significantly reduce heat loss through window openings. But attention to air leaks, and where foam panels are used, attention to fire safety are important as well.
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Reader question: what's the best way to add insulating foam panels at the inside of windows in an older home?
First, thanks for your terrific website, I refer to it all the time. I own a 180 yr. old PA. stone farmhouse with 18 in. deep windows wells and poorly installed replacement windows. Because of the cost for new or authentic windows, I was thinking about sealing them off the window wells with foam panels that would be covered with curtain material or something similar as to be more aesthetically pleasing.
Photo at left, an antique two over two window shown from inside. This photo is from one of our inspections and is not that of the reader who writes below. - Ed.
[Click to enlarge any image]
My idea would be to remove the 2in r10 panels by day and reinstall each night. (This sounds like a pain already.)
They would be positioned in the window well in line with the interior wall to have say 16 inches of air space between it and the window. Is the biggest concern condensation on the inside of the wood windows and are there any other concerns that I should be aware of?
Would the glass shatter due to the cold? Other than the daily removal and replacement of the panels, does this sound like a good idea to you? - J.S. Morristown PA 1/24/2014
Reply: great question, here are some options and some warnings about adding window insulation indoors
My friend Stu Tucker did something like this for his A-Frame home that had a lot of glass. He cut foil-faced 2-inch solid foam panels that would press-fit into the window frames at night but could be easily removed for daytime natural lighting (and for the view).
Our photo (left) illustrates a typical foil faced foam insulating board, this product is Dow's Tuff-R® insulation.
Fire hazards from exposed foam insulation
Watch out: if you leave foam insulation exposed indoors in a living or occupied space, you are violating building code and creating a fire and smoke hazard if you leave unprotected foam panels exposed in an occupied building space. Details are at FOAM BOARD FIRE COVERING where we explain the fire and dense smoke issue.
So the biggest concern with exposed foam insulation is safety, not condensation on the windows.
Effects of insulation on window condensation
What about the effects on window condensation (on the window glass interior side) when you install an insulating panel? Actually you are stopping the movement of moist interior air against the cold glass and thus will be reducing, not increasing, the condensation rate; the insulation itself also reduces the condensation rate as well - we've pushed the dew point outwards.
Our photo illustrates interesting un-insulated windows at Frank Lloyd Wright's Taliesin West in Arizona.
Make some prototype insluating panels
I suggest making a couple of window insulating panels as a prototype. Use foil faced insulation because of its additional reflective value (and it looks better from the outside too) - and trying them out. If you find you like the idea you could spray-glue-laminate a layer of drywall on the interior or room side of the panels to meet modern fire codes and to reduce fire risk.
That way if you or someone else should leave the panels in place for a time you are not creating the fire and smoke hazard I cite above.
Alternative methods for improving window insulating properties without using foam panels: interior storms or solar shades
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