Discussion About Simple Energy Saving Technique

Bubble Wrap, Petroleum Jelly, and Window Insulation

I thought this conversation might be of interest to anyone looking for quick, cheap, and easy ways to save on heating bills. A lot of the strategies I use are experimental. For example, the idea of coating a window in petroleum jelly, or any thick, viscous material or wax. My thought was that this layer of a relatively heat resistant material would improve the R-value of the window glass, since glass is extremely poor at preventing heat transfer. This idea was meant to supplement the idea of using bubble wrap on your windows. Before you judge, applying bubble wrap is not as bad as it sounds. When done properly, it actually doesn’t look half bad and still allows plenty of light to shine through so you’ll still benefit from radiant heating and natural lighting.

Anyway, to get bubble wrap to stick cleanly and effectively to the window for a relatively long time, all you have to do is spray the window with water so that the contact points are moist and the plastic will cling to window. It will stay clung long after the window has dried up and the wrap will remain taught and secure.

I wanted to expand this idea by adding another layer of protection, this is where petroleum jelly came in. But I’m no expert so I asked the guy who is.

Doorknob Koozies

Ever notice how cold your doorknob gets in the winter? This is because in many cases the doorknob acts as a Thermal Bridge. This means the heat travels very efficiently from the inside of the house to the outside because it moves very easily through the doorknob itself, compared to other components such as the wall or door itself. Other examples of thermal bridges include wall studs which are not insulated and windows. I wanted to know if the use of a koozie, or koozie material, would act as a thermal break.

Turns out they probably do. Below is a discussion about both concepts mentioned above (petroleum jelly and koozies).


Hi, I recently read an article (http://www.builditsolar.com/Projects/Conservation/bubblewrap.htm) about using bubble wrap on windows for insulation.

 I had also been thinking of additional small things I could implement around the house to reduce any heat loss. Some things that came to mind was the idea of coating a thin layer of petroleum jelly over the window before applying a film or bubble wrap. Is there any R-value added to this technique? Also, I was thinking that adding coozie material over the door handles it would act as a heat break (the knob being the heat bridge).
Any thoughts on these implementations, particularly the petroleum jelly since I can not find resources online. Thanks!

Build It Solar:

Hi Devin,

Interesting idea on the door knob coozie —  a rough estimate of the saving might be to assume that the heat transfer from cold door knob out would be about 50 BTU/sqft-F-hr, so if the knob has an area of (say) 0.2 sqft, and its 20F outside and 70 F inside, the heat loss through knob would be about (0.2 sqft)(70F-20F)(50BTU/sqft-F-hr) = 500 BTU/hr.  That seems like a worthwhile saving.  Will have to think about this some more.

I don’t think that the petroleum jelly layer would be too effective.  I don’t know the R value for (say) a sixteenth of an inch of jelly, but for materials like wood or plastic it might be in the range of 0.5 to 1 R per inch, so 1/16th inch might add about R0.04.

Things like glass and the bubble wrap get almost all of their added R value from the still air layers on each side of the glass or poly film — the glass itself adds almost no R value.  So, a layer of something like the jelly (I think) would not do much because it does not add another air layer.


There you have it. Doorknob koozies will probably contribute to energy savings, but the petroleum jelly is probably not worth the mess and hassle even though I still feel it would help a little as a thermal break across the window. Petroleum jelly has a much better heat retention ability than glass.

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