Insulating windows

Hi,

I'm using interior window covers that are a four layer:

Cloth
Mylar (shiny silver)
batting
Cloth *added by the end user*

The first three layers are called Insul-Bright

Thanks, Don.

Insul-Bright looks interesting. Looking at the link and some results from Google, I think it has potential for my situation.

How do you hold the end product against the window? How well does it reduce condensation on the window glass in cold weather?

Wayne

Hi Wayne,

I surrounded each window frame with velcro. That way the frames can't conduct heat to the outside world.

I had no condensation issues--but I live in an extreme cold region. Your circumstances may be different.

I used it over windows, skylights, vents, the entry door, and also made a "blanket" to separate the cab. A total of 27 yards of material.

Crack open a roof vent to allow that high moisture laden air out.

What is generating all the moisture? Just the inhabitants or are you cooking with gas? I just got back from a trip to the Grand Canyon and it was so dry I ran a vaporizer or boiled water to raise the humidity level. I was proud to have a little condensate on the window.

Dick

Air flow from an open vent will certainly help. Check out Reflectix. You can buy it in rolls at HD or Lowes and cut it to fit each window. It will hold its shape and stay in place. Popular with the popup campers for preventing condensation on the tent canvas.

Here in the southern mountains, we can get big temperature swings between nighttime and daytime. Going from 20’s overnight to high-70’s or even 80’s during the day is not uncommon.

I’ve kept an overhead vent open, and even cracked windows by an inch or so, without it helping much. There’s simply more moisture in cold-season air here compared to the air much further north. Lots more. Plus, I’m breathing, washing, and cooking with gas in a small heated space, all of which generates moisture in the air.

My main concern is cutting down on condensation. Reducing heat loss would be a welcome bonus.

I’m thinking I would need to avoid creating a dead-air space next to the glass, unless it was sealed from moisture intrusion from the inside, such as the windows that now have the heat-shrink plastic. I think creating an unsealed dead-air space between glass and insulation would probably do as much to encourage condensation.

I’ve been wondering if there is something I could insert as an insulating layer pressed against the glass at night. Remove during the day. Something to separate the cold glass from the moist inside air and minimize contact between the two.

I’ve been determined that our next RV will have dual pane windows. But that limits our purchase options, since dual pane is not even available as an option to order on a lot of RV’s. It would make life much simpler if I could figure out a workable alternative.

Reflectix may help, particularly if I can press it inside the frame next to the glass. I'll check that out. Thanks!

Wayne

Hi,

The roof vent by itself will do little. A window needs to be opened a bit, too. It works even better if an electric heater is placed beside the window to warm up the incoming air.

Two strategies are at work. Condensation happens when surfaces are below the dew point. So warm the surface up. Reduce the moisture content of the air. Where I am full timing interior relative humidity is 15% or less.

I think I've given ventilation a fair try, with little success. Electric heat is not an option because in spring and fall I'm in a Forest Service CG miles from the grid, and generators are not allowed at night due to quiet hours.

I usually keep the interior heat set at 55 during the day and usually off at night. With a vent open and a window cracked by an inch, I'm not sure what else to try in terms of ventilation.

I think 15% relative humidity would be near impossible to achieve here. Right now, it's 34 degrees F and 66% relative humidity outside.

As an example of what I'm dealing with: It's difficult to keep the windows of a vehicle unfogged this time of year around here. Whichever genius at GM decided that in heat or defrost mode the HVAC system in my truck should be programmed to bring in outside air and disallow running the AC compressor below 34* or so, with no override, should be taken out and flogged. I'm bringing in damp outside air and making things worse!

Best solution I've found in the truck is to set it to bi-level AC so I can recirculate the interior air, shut off the dash vents, and wait for the air inside to warm up enough that the relative humidity drops enough to clear the windows. If it is warm enough outside that I can also run the AC compressor, the combination of AC and recirculating is the best way to de-fog the windows. In our other vehicles, I can override to recirculate and run AC compressor in heat/defrost mode, regardless, and they are much easier to keep the windows clear. Just the reality of the cold, damp air around here in springtime.

Wayne

Hi Wayne,

Temperature where I am at now is 9 F, out door relative humidity is 79%, indoor relative humidity is 15%.