Help, film on inside of windows


We have a reoccurring cloudy film that develops on all of our interior windows. We have lived in this house for over 20 years and never had this problem prior to this winter. In the past 3 months, we have washed the windows 3 times and the film keeps coming back. We are a high mountain desert climate and do not have a moisture condensation problem. We heat our home with propane gas and would like to know where to start looking for a solution to this problem. We are in our late 60’s and worried about air quality.


Buy some distilled water and put it in a spray bottle and spray Windows. Use a quality microfiber to wipe the glass down until fog goes away.

Here is what i recommend:



We are not asking how to clean the windows. We need to figure out what is causing the problem.

We have no idea where or what to even start looking for .

We are hoping someone has had a similar problem and can tell us how to figure out the cause.


assuming you don’t have failing IG units

natural or propane gas heaters leave a white film on glass from the burned fuels, if it’s colder than it has been or there’s been a change in equipment that can do it

just like dashboards in a car, any kind of plastics can leave a film as they heat up, perhaps there’s been this type of change in your home or in the hvac system in your home

fireplaces, candles and incense leave a film on glass as well, esp candles made from petroleum products

kitchens leave a film on glass - a change in equipment, eating habits, food preparation products (home fryers) will make a difference

BBQ’s/smokers by an open window with the smoke going inside the home will make a difference

portable firepits outside near open windows (gas or wood) will make a difference

also this could have been going on for years but you never noticed it before but you may have made changes to your drapes/blinds/shutters that allow more visual awareness or just having things open when previously they weren’t will change your focus on the view

most common is you are just running the heater more and the house is closed up more - in 6 months there will be a definite white film on the glass


Excellent troubleshoot.


Thank you, Bruce,
I will start with the gas company. I had a gut feeling that it was something to do with the furnace. It is of a whitish in appearance. Cleans relatively easy with vinegar/water/dawn solution,

We live remote and do not have much in the way of window treatments. We would have noticed this before because it really obscures our beautiful view.

I do not use candles and our windows are all closed, except I crack one in my bedroom, I have had a fear of fumes since this fogging began. It has been colder this year and we seem to need more heat as we age.

Again, thank you for your help, at least I know where to start.



If you are cleaning your windows with dawn and vinegar you will attract a film over time.

listen to the guy above and use distilled water and a microfiber.
I would add rubbing alcohol to that mix also 50/50.
Better yet hire a pro to clean this with a squeegee or learn to use a good squeegee

You CAN NOT get a good window cleaning with vinegar and dawn. you will get a haze every time.


Pro’s do not seem to want to come to our remote area and until we get the problem solved it would be every other week :frowning:

I will try the different solution and we are calling the gas company in the morning. We had a new on-demand propane water heater installed in July and our furnace is older.

I am wanting to see this problem solved, we have lived here for 20+ years and this is a first.

Thank you all for your input.



Gas fireplace. I see this a lot as a longtime window cleaner. It never fails, every time I see that greyish haze they tell me the fireplace gets used a lot.

I’ve seen it so bad the haze runs off black. Gotta be careful dripping on their carpet.

You can certainly buy basic WC tools yourself, brass channel Ettore and scrubber, then a healthy squirt of Dawn in ~3 gallons of water.

Standard Dawn and a good scrubber/squeegee takes it right off and typically doesn’t build back up for months.

It could be your heating unit as well, can’t really comment about that being a source.