Solar screens or better attic vents?

C

CottonEyedHorn

1,000+ Posts
We're debating putting in 90% solar screens on our west-facing windows. Does anyone have these installed and can testify to their effectiveness? We're also thinking of putting in more effective roof vents. Which one is more effective? Cost of installation for both is about the same.

Solar Screens
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http://www.lonestarsolarscreen...n.JPG

Attic Vents
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This is the type of roof vent we have right now (there are about three on our roof):

roof-vent-1.jpg
 
Those vents (existing) look like the type that come with an electric fan. If the fan isn't working, they probably aren't doing much good.

I think the method of choice for attic ventilation these days is a combination of ridge vents and eave openings, to allow air flow in from the eaves and out the ridge. Also, a radiant barrier can be installed inside at the roof.

Austin Energy
 
I don't have any experience with solar screens, because I don't like the way they look. But, I added a second floor to my house a couple of years ago, and I not only installed a ridge vent but also installed a radiant barrier . . . and my HVAC bills went DOWN. The new configuration of the house is almost twice as big as it was before, with the same roof area, yet my bills went down.

My point is that a ridge vent and radiant barrier are a highly effective combo. Whether or not they compete with solar screens is unknown to me.
 
I just had the radiant barrier paint added yesterday to our attic and our upstairs was noticeably cooler when I got home from the office. Amazing stuff. I can't wait until my next electric bill.
 
on a similar note. does anybody know what I can do the cut down on the heat generated by a skylight. I currently have a custom blind built behind it, but the covering on it is still somewhat translucent and it gets pretty cooking up in that space.

I've contemplated having it tinted, but I'm afraid that after a while the film will bubble up.
 
I added solar screens to my house a few years ago and they made
a big difference in the temperature inside the rooms where they were
added.

More ventilation in your attic would also be a good thing. Radiant
barriers are probably the next thing to do, simple to install and not
too expensive.
 
I have solar screens in my existing house and they cut my bills about 40% when I installed them.

Good attic circulation is a must even with solar screens.
 
I saw a tv show a couple weeks ago that had an attic fan that you could replace a vent with, it was solar powered so it didn't cause any increase in electric bills and supposedly really helped on the electricity. I can't remember what show or what it was called though, but I wanted one when I saw it.
 
We had extensive solar screens on the west facing windows in our previous house. We also had a solar screen made for our bathroom skylight. They definitely helped reduce heat gain. We had LOTS of west-facing large windows and virtually no attic, so I know the screens were more effective in our case.

The down side of solar screens is that they are thicker screen material than standard screens so they distort your view just enough to be annoying. If they solve your heat gain problem, however, that would be worth it. Another solution, albeit more expensive, is to replace your west windows with low E glass. Your view will not be distorted and they will cut the heat gain noticably.

On our previous house (aka "The Heat Sump") we ended up with low E glass on the upstairs windows, built an arbor across the entire back of the house to shade the downstairs windows, and left the solar screens on the bathroom sunlights. The sad moral to this story is that you may have to use several methods to reduce your home's heat gain to a comfortable level.
 
Ok, this is my second time to try and type this. Let's hope I don't lose it again.

It seems like the overall tone here is to try to make your home more efficient, so I'd like to offer some advice on various ways one might do. All have their benefits and are more applicable to your case than others, but I think it's good information nonetheless.

There are several strategies that one can emply, all with varying levels of complexity.

First, there's the issues of attic ventilation. No system, whether pasive or mechanical, will be effective unless there's proper venting. The most effective system is having an continuous ridge vent coupled with soffit or gable-end vents. This will allow your attice to draw cooler air from the overhang and let the warm air out at the ridge. You can get similar effects from mechanical vents, but from what I've seen they're not significantly better than a continuous ridge vent. The important thing is that you have vents both low and high in the attic and a clear path between them.

As far as radiant barriers, one can use insulation that has a reflective surface on the top to act as a heat mirror and bounce heat back out of the attic. However, a more effective approach is to use a reflective paint on either the top or bottom of the decking. Bouncing light at that point helps keep it from ever reaching the air in the attic. One can also buy plywood decking that has a reflective coating already on it.

Another thing i've noticed about both attic insulation and wall insulation is that for years it has been installed improperly. For instance, blown-in attic insulation tends to compress over time thus reducing its R-value and slowly decreasing the effenciency of the home. Also, for years, in-wall batting insulation has been installed between studs without any mechanical fasteners, basically staying in place by friction. Over the years gravity causes the insulation to slowly creep down the wall thus leaving cavities in the top of the wall where cool air can escape. Newer systems have been implemented that allow the user to staple the insulation to the studs thus preserving it in place. An alternative to batting insulation is sprayed foam insulation, which is becoming the more preferred solution because its application leaves very little chance for there to be insulation gaps.

Another great way to help keep your energy costs down is to prevent the summer sun from ever hitting your house's envelope and/or fenestration. This can be accomplished by planting trees along the side of the house or to install man-made solar shades. The latter can be done with horizontal (for the south side) or vertical (for the east and west sides) louvers or solar screens as mentioned in the original post. The one drawback to louvers is that they're a contemporary solution that may not fit with most traditional-style homes. The problem I see with solar screens is that they are not very attractive and can actually distract from the look of many houses. Another good solution is to use Low-E glass in your windows, but that's a whole other thread.

One thing to keep in mind in Texas is that one needs to not only try to protect the house from western sun, but from southern exposure as well. There is actually more heat gain on the south side of buildings in Texas because there is constant direct sun exposure on that side of the building. It's not as direct as the western side, but it is present for longer durations.

If you can't block the sun from hitting your house (with tree cover), then the next best thing is to make sure the house is properly insulated, the attice ventilates well and to make sure direct sunlight is shieded from coming in through any exterior glass.

Anyway, that was a long explanation, but I hope it was informative. Please feel free to shoot any other questions or if you want clarification on anything I've stated here.
 
Also, to answer the original question a little more concisely, you will get much more benefit from proper attic ventilation and insulation, so I would put your money there first. If there's anything leftover, then buy solar screens the windows in your house, but you really will only need them on the west and south sides. You may want them on the east side, but there isn't enough harsh sun on the east side to make that much of a difference. You do NOT need solar screens on the north side since there is never any direction sun on the north side in the summer in Texas.

Ok, so that wasn't very concise, so shoot me.
 
OK, this is a really stupid question. I've got the attic roof vents with the electirc motors. On both these vents, the motors have stopped working. Who do I call to get this type of work done in Houston? Any idea how expensive it is to replace these motors?

Thanks in advance

MAROON
 
We had a vent ridge put in when we had a new roof installed last year. We have plenty of soffet vents around the house & it's certainly made a difference.

We also had solar screens put on around the same time although I believe we went w/ 75% rather than 90%. The installer recommended going w/ the slightly lower efficiency screen because the 90% screen is such a tight weave that he found it made opening windows for cross ventilation during the spring & fall almost useless; it's almost a solid material rather than a screen at that point.

3M also makes excellent solar window tinting for home applications. My BIL who lives in Spring just had his western windows done & he's already delighted w/ the difference.
 
Have any of you used solar panels to take over some of the power needs for your home (for example, to run 1 or more of one of the following: Pool heating, hot water heating, air conditioning, appliances)? What are the pros and cons of current technology? Would your recommend it as a supplemental power source? Is there a good source for additional information?
 
There are plenty of good resources you can google up. The main problem with solar or wind, as I see it, is that you still need to store the energy and the batteries are expensive and less than perfect. Little things like air conditioing and refrigeration tax the hell out of the systems. Heating water and pools make sense, but it's really not quite there yet in my opinion.
 
I am very seriously considering solar power to augment grid power for the house I am about to build. The City of Austin rebates somewhere between 45% and 75% of the typical installation costs, which helps immensely. Payback should occur within a few years . . . and that assumes energy prices don't skyrocket.

The batteries are a known commodity. I will look into disposal fees, etc., to get a true cost of ownership. I'll dredge this thread up as I get more info.
 
Thanks. Let me know about the basics as well - What is involved in retrofitting a home, how much it costs to purchase and install a system that is used for augmentation, who are the best manufacturers, and what are the hidden costs (batteries, battery disposal, etc.)?
 
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