Does bubble-wrap work for insulating windows?
 

Does bubble-wrap work for insulating windows?

For $15, I bought a roll of 24" wide roll of bubble wrap, enough for three or four windows (I only wanted to do the lower windows).


On a single glass window with no storm window, it makes a big difference!

I also tried it on single-glass with storm and next on Argon-filled double low-E windows, on each one , the difference was less than the previous test. The difference on double-glass, Argon-filled double low-E window was almost too low to read.

Take-away:

• If you have single-glass windows, bubble-wrap can certainly help. At $15 for several windows, it is tremendous bang for the buck.
• If you have single-glass with storms it will help a little.
• If you spent $300 on Argon filled double low-E, don't bother to invest $15 to cover your Argon-filled windows with bubble wrap.

-AC_Hacker

From everything I have read it works very well.
I would suggest asking friends and/or going to most any store and getting the wrap for free.
To clarify that last line.
Ask for the wrap they received in packages sent to them.

Hi AC,
I had a go at measuring the performance of bubble wrap on our double glazed low e windows back in 2005:
BubbleWrapPerformance

The results looked pretty good -- better than I would have expected by just saying the the bubble wrap adds about R1 to what is already there. Not sure if this is a flaw in the technique I used, or just that the bubble wrap did a bit better than expected.

Based on the double glazed low-e having an R value of about 3 (U of 0.33) and the bubble wrap adding R1, you would expect about a 25% drop in heat loss by adding the bubble wrap.
But, the measurements I took came out at about a 45% reduction in heat loss.

Anyone have a better way of measuring the actual performance?
I now have an IR thermal camera, which would make getting overall window temps easier.
It would be nice to know what the real number is.

Gary

I could have saved myself so much trouble and expense if I hadn't put in 3 layers of 2 inch XPS in the walls (R-30 for 6"), carefully sealed at every layer.

Instead, I should have wrapped my kitchen in bubble wrap.

What a fool I was!

-AC_Hacker

I think you should have just run the 6 inch R30 right over the windows :)

Gary

The view was not so magnificent, anyway!

-AC_Hacker

*Puts flame suit on* I'm actually considering this, removing the wood blinds(which are dark and pull a ton of heat in) and attaching some drapery to the insulation, gasketing the edge and shoving a 2" sheet of XPS against the glass on the inside. Granted it isn't the outside but its also going to be on the front of the house so I'd like it to look somewhat normal. I'm thinking blocking the light will do more than the R10 will but it should amount to a roughly R12 window assembly that kicks the crap out of the performance of low-E gas. Would this work as well as I think it would?

I've been putting rigid foam board in some of our windows. I use the Atlas R-Board insulation in that it has nice light grey face sheets on the foam board that look nice and take paint well.
This is one of my windows:
A High R-Value Window Insulation Shutter with Good Light
I've since added it to several other windows that we don't look out of much. I've only been covering about 3/4's of the windows, leaving a gap at the top to let daylight in.

One inch of the R-BOARD is R6.5 -- its polyiso, so has high R per inch.
You could use 1.5 or 2 inch and get as much as R13 just from the foam board.


Also used the same stuff on our sliding glass door:
Insulating a Sliding Glass Door
I was going to take this out during the summer, but we just decided to leave it in year round as it does not interfere with the use of the door and still lets in plenty of light.


Gary

I came across a similar scheme before that employed a combination of thin 'stick-on' magnet stuff around the window (or door) frame, and thin sheet metal around the insulating board edge.

This made for easy removal/detachment and also good seal.

-AC

Too bad we can't test this idea with Argon filled bubble wrap

wrap the outside of the house and watch the nieghbors looks on their faces:D

I just wrote a quick blog on this because its so easy and cheap to do and I think more people should consider it.

One question I did have though. It looks like AC_Hacker used the bubble wrap with smaller bubbles while the pictures on Gary's site look like he used the bubble wrap with larger bubbles. I'm wondering if the larger bubbles would be superior to the smaller ones? It also seems like AC_Hacker used two layers of bubble wrap versus Gary just using one. Anyway, things to consider and compare.

For my tests, I compared several different windows, the best one was a two pane double low-E, which has the heat reflective coating on the inside as well as the outside.

So when I took readings of the delta-T on that window, the difference was not enough for me (intuition, no calcs) to justify bubble wrap.

For me, the take-away was that the inside reflective coating does matter... a lot.

-AC

Thanks for this thread, I may have to try this. on the south side windows. One thing though... Do the bubbles block the solar radiation? Do you lose the benefit of the sun rays heating the contents of the room during the day?

I haven't measured it, but I'm sure that you'll loose some solar energy during the day.

-AC

I usually put plastic up on my windows, but this year 5 (of the 7) windows i cover I put storm windows on the outside (Menards) and so far, i'm getting no condensation on any of those windows (not sure that means i'm not still losing heat through them)...the remaining windows, i'm still getting a ton of condensation (where on cold days i have to wipe the windows down with paper towel). I haven't tried bubble wrap, but i have built simple wood frames and covered those with cheap 6 mil plastic and put those over the windows to eliminate condensation....but those were a little goofy looking, so i spent the money on the storms.

Any tips on where to likely find the bubble wrap ?
Tips on what businesses may have in in their dumpsters or where to find it would be appreciated, I have a few unused windows that could benefit.

I got mine at one of the big-box home remodel places, Lowes.

They were selling it a a packaging material. Not free, but pretty cheap, if you have any income at all (not a reliable assumption, these days).

-AC

I guess i could afford it :) not really a big ticket item haha but i am frugal.
(nice word for cheap)
If i had to i would buy it.
It seems so right to use materials that otherwise would get thrown away.
I will see what i can scrounge, I thought about using cheap blue laminate flooring insulation i can get from a recycler for a few bucks for a 4x100 ft .
I could tape it together with tuct tape make multi layers and staple it over the frame of the two large back windows, as I never open them up or draw the curtains with.

Its ridiculous really to have such a big 5ft x 6ft window in the bedrooms...

No need to explain. As a species, we are marching to oblivion and leaving mountains of trash in our wake.

Even smart corporations find clever ways to turn their wasted material into profits.

I'm not familiar with this material, but use it if you think it will work.

Dry corrugated cardboard makes a wonderful insulation. If you can put it together in layers that don't leak air, you'd really have something.

You really got that one right... you have a 30 square foot thermal hole in the wall, since a single layer of glass is R-1. And you spend your nights there, so view is of no value to you... horrible design.

Block it up, fill it up,

-AC

I should put 2ft x 4ft windows in the bedrooms.One window is currently fogged making it less effective, if I happen on a pair of the right sized double panes at a used building supply (not always used but left over) I will purchase them and do the switch, the pay back time would be short with a cheap set of windows.

Theoretically you would need bubble wrap that had an air space of over 3/4" in order for there to be a difference, but because the bubbles are separate and not continuous the overall R value would drop to account for the flat spots; it would add roughly another R1 give or take, so if possible it wouldn't matter a whole lot.

There needs to be a control comparison to see how much better bubblewrap is than another basic air tight, low perm covering that adequately sealed around a window perimeter so you would know how much was due to the bubble wrap insulating value over air sealing.

Obviously you get the benefits, but the R value is not likely where its at.
New windows are likely less leaky than old single pane, and storm windows often come with an air sealing retrofit on the outside, so the air sealing nature would provide less benefit as noted by the results compared to each.

Caulking the single panes and gasket-ing the window might provide near the same performance

Why don't you do the control comparison?

-AC

I think .. a infrared thermometer aimed at surface of of the bubble wrap then at the other trial material to compare the surface temperatures could find a winner.
The warmest surface temperature would be desirable I deduce.

Infrared thermometers are touchy, they do not like shiny surfaces so a area sprayed with flat black on each surface would insure continuity in the readings.

I don't know if you have an IR Thermometer, but I got mine from a Chinese Tool Store, for $10.

Sounds like it is time for the science to begin...

-AC

I do have a Chinese one, straight from China off of eBay -58*F to +716*F
The instructions warned of inaccurate readings from surface reflectivity stating to aim for a non reflective / non shiny surface, China shiny ..
Paid $7 for my yellowish orange IR thermometer.

Cheap plastic black electrical tape works very well.

Your meter (similar to mine) may have significant errors in the indicated value, but you can be pretty sure of the accuracy of temperature differences within a close range.

-AC

the Convection needs to be slowed, I remembered that the insulation used in quilts would work well and that People do it.
Scotch Guarded Quilts can be cut in half and resew if desired.
A friend with a sewing machine would be indispensable if you were to go that route, I think I will leave leave the quilt in one piece perhaps folded.

2nd hand prices will make it dirt cheap, tomorrow I will try to find some white'ish quilts , scotch guard them and replace my flimsy curtains in the bedrooms , first anyways.

I see this working out.
I suspect people have been adding quilting to their windows for 100's of Years

From Wiki
on Convection :

Air and other gases are generally good insulators, in the absence of convection. Therefore, many insulating materials function simply by having a large number of gas-filled pockets which prevent large-scale convection. Examples of these include expanded and extruded polystyrene (popularly referred to as "styrofoam") and silica aerogel. Natural, biological insulators such as fur and feathers achieve similar effects by dramatically inhibiting convection of air or water near an animal's skin.

Don't get me wrong, I understand your sentiment.

The intent was to indicate that bubble wrap may not be any more of a miracle than say standard plastic film, which is basically what it is with plastic bubbles on it. And then the degree of miracle is more in its low perm and air restriction; the R value is the skin effect which is about R1 if you seal it properly.

The trapped pocket of air in most cases where one would use this approach would not be insulating as it's not trapped on the window side due to air infiltration - hence why the plastic covering helps so much. The air pocket in a window only has R value because it's sealed.
The more aesthetic and long term approach would be to air seal the window or replace it.
As the test noted it still didn't do much even with a window that probably had a fairly sealed installed as it is extremely difficult to get a true trapped air pocket; windows have multiple gaskets and are filled under vacuum.
Unfortunately the bubbles don't do much as they are not contiguous nor thick enough to have an insulating value - 3/4" is generally what you need for an air gap to have an insulating value. Trapped air in some insulating products is where the benefit comes, but as a whole contiguous unit, if some parts don't have the uniformity it loses sig R value.
Bubble wrap can be free if you can get it wide enough for a window, although it doesn't have a WAF. At the point of using bubble wrap on a home window, one might consider just replacing the window with an insulated wall. The wrap would be equally helpful in hot summers too.

I love the DIY stuff and people sharing info, and my intention is not to stomp on your share, but we should always strive to present a full picture, otherwise we chase shadows and sometimes do more harm than good. There is nothing wrong with declaring a winner with caveats or only in certain restrictions. This type of effort seems more suited to say garages or storage basements and similar type of buildings to get quick cheap help where you can live with the visuals.

We have to be careful not to fall into the candle flower pot heater realm ;)

So what did the tests indicate?

Where's the data?

-AC

I have a window to test.
I will do a small test of the plain glass (with black tape to test off of) compared to some packing material white Styrofoam sheet( black tape again) , 1 layer tested then a 2nd layer.
I suspect I will see a notable improvement.
Also the white Styrofoam let the sunlight threw , it was still effective as a window for light in that regard but not so easy to see out..not that I cared , it's a side window looking over the neighbors house.

I'm going off the test data done by various laboratories that do R value testing and research. I'm sure you've read the same stuff.

What might be more interesting is foil bubble wrap testing, although i'm not sure you could measure the actual results with an infrared gun as it would provide more benefit than measured off just the backside.
Horizontal heat reflectiveness isn't near that of the vertical.

The Rvalue testing measures the change in the environments on each side of the insulator, not the backside temp change. The back side temp is useful in window testing for feel it provides when you are next to it as the difference is dramatic.

I think that if you look into this, you will find that radiant energy travels equally in all directions, and the ability to reflect radiant energy is equal in all directions as well.

However, if the convective effects of air movement are considered, then the "R-value" will be different with different orientations.

-AC

1/2 inch white Stryfoam vs single pane
 

Styrofoam results

On one side of the window's half section the Glass was left exposed.
The other window's half was covered with 1/2" thick Styrofoam sheet 2'x3ft. top to bottom.

Test #1
Bare single pane glass - 54*

(1 sheet ) Styrofoam - 63.2*

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Test #2

I added one more sheet of Styrofoam, for a total of 1 inch thickness.

Bare single pane glass - 53.2*

(2 sheet) Styrofoam - 63.3*

Outdoor Temp was 31* in both tests

About a 10 dgree improvement.
Strange there was no gain from the 2nd sheet of Styrofoam, I double checked the Data.