heat reflecting window film

Poppy

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I just spent $100 on Gila "Heat Control window film." "Reduces Heat and Glare... Not your View"

If it works out well, I may have to spend another $100 to finish the rest of the windows. I wonder if it will be worth the cost.

Would it be removable during the winter and then replaceable? It is nice getting that free heat during the winter.
 

raggie33

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I need that so bad my front of home is in thr perfect dirrection towards sun . everything in front is uv damaged killed my ring doorbell and door and windows makes it so hard to cool room
 

Lynx_Arc

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I would have recommended white blinds on the windows myself as you can block the sun with them and move them out of the way in winter if you want to. You can also put heavy blankets on windows to block the sun and also keep the cool in. In the winter you can just pull them up and out of the way of the sun if you need to.
 

Poppy

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Thanks for the reminder. Cody Lundin, in his book "98.6 degrees" mentioned using Mylar survival blankets on walls, or ceilings to reflect heat in or out of a room. While they don't allow one to see through them, they may look the same from the outside, as the film I bought. I have way more glass than I need. The shades are usually 80% down on all of the windows.
 

kerneldrop

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I’ve got ceramic tint on my truck windows and windshield. Different % tints, but all turn away heat.
the difference is night and day.
My wife’s vehicle has the better 3M tint all around including windshield and it’s even better than mine.
it’s hard to believe, but the tints do work.
 

Lynx_Arc

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I’ve got ceramic tint on my truck windows and windshield. Different % tints, but all turn away heat.
the difference is night and day.
My wife’s vehicle has the better 3M tint all around including windshield and it’s even better than mine.
it’s hard to believe, but the tints do work.

They absolutely work. I have had film on my car I had back in the late 80s and before I had to put on I could feel my arm getting hot on the
door arm rest, after it was on I felt nothing of the sun. The main problem with film is in the winter it doesn't let the heat of the sun in either
and doesn't do much to keep the heat in on top of it all unless maybe your heat is from incan lighting.
 

Scotty321

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Jan 13, 2021
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I just spent $100 on Gila "Heat Control window film." "Reduces Heat and Glare... Not your View"

If it works out well, I may have to spend another $100 to finish the rest of the windows. I wonder if it will be worth the cost.

Would it be removable during the winter and then replaceable? It is nice getting that free heat during the winter.

You are basically referring to passive solar. If you don't need the view, white shades can help bring in the light, and give you more privacy, especially in the night. If you like the view, rock on with your window film.

If you want to play with passive solar in the winter, take the film off. It also helps if your floor is ceramic or porcelain tile with the sun shining on it. The tile will retain some of the heat. Even better on concrete floors or brick/stone interior walls. You can also play around with stone decor to help absorb and retain some of the heat. In the winter, you can get drapes that help block window drafts on the side of the house that doesn't get much sunshine, but it is a bandaid for poorly insulated windows.

Be aware, if you try to play with the sunshine for heat with wooden floors, the sun will lighten the wood that is not covered and leave silhouettes when you move furniture or carpets. I would not advise this.

Some other tricks...

If you have the old style windows (like from the 50's), replace them with the more modern windows that have a decent R value. Even storm windows don't make as big of a difference on those old style windows as the newer windows with insulatory value.

If you have a screen door, replace the glass with a screen in the summer, and back to the glass in the winter.

Check in your attic that the insulation was installed correctly, hasn't gotten wet from a leak in the roof, and that the ducts running through your attic are insulated properly. Additionally, check that the bats were cut to the correct dimensions and aren't bunched in because the installers were too lazy to make those last few measurements or cuts. If the house is old enough, it may also have old sawdust and tar paper insulation in the walls. You should replace it with the newer fiberglass insulation... remember that the Kraft paper should face the inside of the house, and make sure not to squish the insulation significantly, as it reduces the R value the more it is compressed. Always wear proper protective gear and respiratory gear, as you don't want fiberglass in your lungs and it is irritating on your skin.

Attics can get very very hot... sometimes the access panel to the attic can cause heat loss in the winter, or heat gain in the summer. It might help to make sure your attic access panel/door is properly insulated, and that the door's support/frame has insulation in the small nooks.

Attic ventilation is another significant factor, but I haven't had significant experience with options to comment.

Getting back to the sun block, one of my vehicles is parked outside most of the year. In the summer one of those $10 reflective windshield shades made a huge improvement to reduce the heat buildup inside. I had to replace it after about 8 years... well worth the $10 cost.
 

Poppy

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Lots of great tips here. Thank you all!

This house was built in the 1950's on a slab with hot water radiant heat in the floor. About a year ago, pergo type vinyl flooring, over 1/8th inch foam was installed. It seems that it takes a long time of the furnace running to build enough heat in the slab, and to get through the foam and vinyl, to raise the temp in the house a degree or two. The problem is that there are so many calories in the slab after the furnace kicks off, that the temp in the house continues to rise. That coupled with the solar gain of the living room windows, the temp may rise to 79 degrees F. Although the thermostat is set at 71. On cold winter days, there is enough energy loss that the temperature swings are less dramatic.

About 1/3rd of the house is an addition, 2/3rd of that has baseboard heat. 1/3rd has no heat other than a gas fired fireplace, with an 8 foot opening to the dining room. I think that the AC unit is a little undersized. It probably was not resized to accommodate the addition. So I have more of a problem cooling, than heating.

I replaced the (non functioning) motor on the belt driven 36-39 inch attic fan, and put it on thermostat set at 100 F. That made a significant difference!

The windows are in good shape although they have some years on them, but they are at least 3/8 inch insulated glass.

We do have accordion type shades on all windows. I think they help a little, but the shortwave sunlight is converted to longwave as it passes through the glass. Once it gets through the glass it is heating up the air and the shades and curtains. I think that if it is met with a reflective material adhered to the glass, THAT would be much more effective in reducing the heat of longwave radiation.
 

Chauncey Gardiner

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Excellent post, Scotty321! :thumbsup:

We've been rockin either plastic or Bamboo blinds on the exterior of our southern and western facing windows for years.
I like them for a number of reasons:
1. They keep the sunlight from entering through the window, which takes it toll on interior blinds, and "super-heats" the air between the window and the blinds.
2. They protect the wood windowsills which cuts down on painting.
3. We can still enjoy the yard due to being able to see through them.
4. They darken the room a bit, so we don't feel like we're living in a Lightbox.
5. They're easy to remove and store come Autumn.
6. They're relatively inexpen$ive.

hfyGGYM.jpg
 

Scotty321

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Seems like you have a multi-layered list of things that could be improved... I'm working on a few myself.

Although I might offer up some suggestions, it is probably best to get ideas or estimates from a reputable HVAC company... especially if they are familiar with older houses and your hot water radiant heat floor.

Just some thoughts... You might want to spend a couple bucks on those $10 digital temp gauges and place them in different rooms to see what the temperature variant is. Personally, I purchased a a Flir One thermal camera for my Android phone when they were half off (older version) and I track down heat leaks with it. This might give you a better idea of how bad the heat differential is, and what rooms/walls might be the biggest problems.

Simple options (although more of a bandaid) might be to look into a "duct booster fan" for rooms that need more cooling... this can get complicated with the labyrinth of ducts that were retrofitted into older homes (the further down the duct towards the furnace the better as they make noise). Another option is to use a ceiling fan to help normalize the room temperature through circulation.

Side note: Make sure your return vents are not blocked by furniture, and that your supply vents are aimed toward them to aid in room circulation.

Side note 2: I would check that the fireplace damper is closed properly.. don't open it if it is. I found some of ours were wedged slightly open from debris and use from a previous owner. You might also look at fireplace doors that have insulatory value.

Side note 3: Most HVAC people that I've spoken to suggest using the lower MERV rated filters for increased flow. I sometimes use a room air purifier if I think the air needs to be "cleaner," for example with my family member with asthma.

Pics for fun! :D

These were taken in the winter. Blue is colder, yellow is warmer.

Here's a pic of a closet with attic access I took while trying to figure out where to add or modify insulation. It turns out that the insulation on the right corner was non existent because of the beam placement, and the bottom dark blue area had insulation compressed and mangled because the contractor didn't want to cut that piece to fit properly.. and it was installed backwards with the Kraft facing away from the wall:
YpSV23qnpK1ZPzG7XX3_aByRTC8bHcTxv_0GcQqcaWhj9J0deqOcKvhzycaAAqY4dy3l_k0Kenffcc6_PJbnRrQ2-n1DP_etmak4qM0_iWoqdgzLzReBMtwZabGRD4JY2iVKjrjkuw=w2400


Pic of fireplace with a brass and glass door plus face brick:
Mvcbs3durmu8ef52wH49i9UGdjUp3E0Nt3J6CC0VnEbpw1-KsBGwqxC3Tg_yyq8fYw6Y75KmzJNhYrvqYiEjT-ka1SvjYAnytQhreo9y3miupry5H66V9eNjsgHmkGftTCGdm3_1Ug=w2400
 
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Lynx_Arc

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There are other simple solutions for hot spots in a house too. When the temps outside and inside aren't much different the normal blower setting of AUTO doesn't have the blower running and heat can build up and setting the Blower to ON can continuously cycle the air in the house. Also you can put a fan outside of the hot room and blow cooler air into the room from the floor which can push out hotter air in the room. Ceiling fans help but don't push air out of the room very well they just mix it up so the cooler air on the floor is in the middle but the hotter air at the ceiling can also be mixed in the middle too. Turning the ceiling fan reverse can move hot air down the walls and pull the cool air up the middle but if you aren't in the middle only the breeze helps you be much cooler.
 
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Poppy

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Once again, thanks for all the thoughts.

We installed the Gila "Heat Control window film." "Reduces Heat and Glare... Not your View" Titanium, on the South facing sliders to the deck, and on the skylight. That made a significant difference, in the family room. The problem is that it blocks some waves of the spectrum, such that it gives the room a little bit of an angry/cool blue tint. My daughter doesn't want to put the film on the living room bay windows, but would consider it if it was removeable.

Gila does make a slightly thicker film, they claim is removable and reusable, for double the price, and in a size that would insure a lot of waste for my size windows. Again, that would give the angry blue tint, that neither of us like.

During our 4 day 112 F heat wave, I hung a reflective tarp from the rain gutter. That looked real trashy, but I was more comfortable. My daughter was away for a couple of days, and I thought that she would have a *fit* when I showed her a picture, but to my surprise, she was OK. Then I left for a couple of days, and she had hung the tarp on the inside of the window. Not as effective, and not as trashy.

Gila makes a film installation kit. It is a spray on solution, that I guess increases static cling, a squeegee, and a trimming/cutting tool. I decided to use it, and a three dollar Mylar emergency blanket, to cover the lower 2/3 rds of three of the five panes of the bay window. That worked pretty well. The Mylar is really thin and wrinkled easily, so it is not a perfectly smooth installation as it would be with the Gila film. There is still plenty of light, much of it indirect, and it has the natural full spectrum... no blue tint. The top 1/3rd of the middle three panes is shaded by the overhang, and the two side panes are at an angle, and get more shade from the over hang because they are not as close to the outer edge as the center panes.

The shades hide the mylar from the inside, and with 50 foot set back from the road, a man on a fast horse, riding by, would never notice it from the outside. Come September, I'll peel that $3 Mylar blanket off, and throw it away.
 
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