Customer Reviews

Solar Attic Fan with 25-year Warranty!

5 star:		(6)
4 star:		(5)
3 star:		(0)
2 star:		(0)
1 star:		(1)

 

 

After quite a bit of research, I felt that the Natural Light Systems Solar Attic Fan offered the best combination of engineering, quality, and value compared to competitors. As for performance, I conducted a simple test that is reported below, but am not equipped to compare other brands under the similar conditions. Unfortunately, I couldn't find unbiased brand comparisons.

The product sold here is a 10 watt panel unit manufactured in Phoenix, Arizona by Natural Light Systems ([...]). The company also makes a 20 watt panel that costs about $75 more that will probably prove more satisfactory over the long run. The only difference between the 10 and 20 watt units is the panel.

BACKGROUND
I have a house with a moderate pitch (I believe about 15 degrees or so), with a black asphalt shingle roof, located in Mountain View, California. When re-roofing the house a few years ago, the contractor recommended installing several small "eyebrow" vents opposite each other along the ridges. They take advantage of the Venturi effect to exhaust hot air. They really weren't sufficient, though. Wind turbine ventilators were too small to retrofit and obtrusive, and over the years I've 1) installed (and removed) a gable fan (noisy and inefficient), and 2) finally re-engineered a large Vornado fan to direct exhause out of a leeward vent. But it was still a bit noisy and used electricity, of course.

Hence, the search for a low-profile solar attic fan, though, I did consider a new passive system from Aura (see [...]). That company also has a solar panel version, though there are some features I don't particularly care for. I installed the solar attic fan on the leeward side of the house, facing due south, in place of an eyebrow vent, in the center of the house. I sealed up the opposite windward eyebrow. There are sufficient air intake vents (or soffits). Total attic volume is somewhere between 1,500 and 2,500 cubic feet.

PROS
Simple and straightforward engineering. This unit comes with a single well-designed fan. One brand that I nearly bought, from Aura, is cluttered with several little fans tucked inside the unit.

One piece heavy gauge stamped aluminum body with no seams. The seamless body is leak-proof with no additional caulking needed.

Aluminum and stainless steel hardware, so corrosion shouldn't be a problem.

High quality BP solar panel (the 20 watt panel, which I have, appears to be the BP-SX320). I understand that most panels degrade in performance over time, so think it's better to start out with a more powerful panel. The solar panel is adjustable - great if you can easily get on the roof and want to pick up the rays from the low spring or fall sun. Out of the box, the solar panel rests flat against the top of the unit; the picture shows it in a raised position.

High quality fan motor and blade; easily replaceable if needed. Extremely quiet - I can't detect any noise from the unit inside of the house, and just a slight whooshing a couple of feet away outside on the roof.

Twenty-five year warranty, thought it's only as good as the company stays in business. I called customer support and found them friendly and knowledgeable. I think the only parts that could potentially need replacing are the fan motor and panel.

Low profile and neutral color helps it blend with many roofing materials and not stick out like a sore thumb.

CONS
Installation is, like, all such roof hardware, a little involved for an average homeowner like me. Just take it easy and, as they say, "measure twice and cut once."

The company provides a silicone sealant, which I regret having used since there are stainless screws holding the unit down. Probably needed for regions where winds get fierce, but I don't think for my area. The silicone gummed up the wires for the thermostat, though didn't do any harm (fortunately, I could clean them off after installation because I have access to the attic).

The solar panel is a bit tough to adjust. I would have appreciated wing nuts rather than Philips screw heads that could easily get stripped.

CONSIDERATIONS
I recommend getting the thermostat, which is a $20 optional item.

Mount on a southern exposure, where there is sun all day (or at least from 10 am or 11 am onwards). In shade, the fan, which is continuously variable speed, will not operate. I believe it will operate, though at a low speed, on a cloudy day. Essentially, the more sunlight, the faster the fan will rotate, hence exhaust more attic air.

I recommend the 20 watt panel over the 10 watt panel.

You will need to cut a 19" or 16" round hole in the roof (depending on your rafter spacing). 19" is actually fairly large (and what I cut) and will vent a lot of attic air.

Solar panels get dusty which can affect their performance; and birds do perch on them, so direct a little garden hose spray up to them occasionally if it doesn't rain a lot in your area.

DOES IT REALLY DO THE JOB?
I thought I'd conduct a simple test to find out how the unit performed in "passive" state (sans fan) and "active" state (with fan operating).

The set-up: I had one remote digital thermometer in the attic about 8-10 feet away from any vents and midway between the floor and ceiling of the attic, about 20 inches off the floor of the attic. Another thermostat was placed in a shady spot on the patio away from the house.

The test: I chose two comparable sunny, mild days (75 to 76 degrees F. on May 27 and 28, 2009) with a breeze out of the northwest at about 5 mph. On the first day, I covered up the solar panel, so the vent became passive. On the second, the panel was uncovered and the vent was active. I took measurements roughly every hour from noon to 6 pm. I found the patio temperatures peaked on both days at around 76 degrees from 3 pm to 4:30 pm.

The results: During the hottest parts of the day, the attic temperature was 39 degrees greater than the patio temperature when the vent was in passive mode. In active mode, it was 33 degrees greater. The fan, therefore, kept the attic up to 6 degrees cooler. On the first day, I removed the cardboard cover on the panel, allowing the fan to operate, at 4:45 pm (the inside of the house was getting a bit uncomfortable). Within 30 minutes, the attic temperature had fallen 5 degrees.

Subjectively, the house seems cooler with the solar attic fan than even with the Vornado - and quieter. Haven't tried it on hotter (85 degrees +) days but expect the 30 to 35 degree differential between attic and outdoor temps to continue. If you have a lighter color roof than mine, the reflective properties should reduce the temperature differential. Note that every roof and attic is unique in some ways - with different gable profiles, intake and exhaust vent arrangements and so on. I found these websites helpful: [...] [...] )

CONCLUSIONS
Some experts think that solar attic fans are a waste of money because they're under-powered with unproven life-expectancy. I was hesitant to buy one, but felt this brand offered solid engineering and construction, an unobtrusive low-profile, a powerful enough solar panel, and a great warranty. After a month of living with the fan, I am completely satisfied and unhesitatingly recommend it.

UPDATE
I deleted a star because, as my roofer pointed out, the flange is not completely flat, but channels water away from the fan housing and possibly under roof tiles. The lip is also a bit narrow. This is not a good design. We did have a leak that was fixed by applying copious amounts of roof sealant to the tiles.

I looked at a few similar units in local big box stores and I was pretty disappointed. Other fans are made of plastic, or cheap thin metal. This fan is very substantial, very strong and durable. The extra weight does have a drawback in that it's a bit more challenging to get the unit on the roof.

Minor tip: I covered the panel with carboard to stop the fan while installing, but afterwards, (duh), I realized that I could have just unhooked the wiring.

I also detached the panel and fan from the base before the install. It makes it a lot easier to sink the screws in the base into the roof. Next time I will disassemble the unit on the ground and then bring it up and install in pieces.

I wasn't able to simply lift the upper shingles. You really have to remove a few to properly install the unit because the holes for the upper screws are too far back, and using enough sealant would be a challenge with the shingles in place. No big deal, but I think the instructions encourage you to think that the installation is easier than it is.

The included sealant would not be my first choice. I ended up using a SikaFlex-like product from Henry.

I can't quantify the improvement once the fan was in place, but I can tell you that it whirs away all the time the sun is shining, definitely moving more air than the passive setup I had before.

The temperature switch might be a good idea for winter conditions. Hard to say because on the West Coast where I live, humidity is only a problem when the sun is not shining.

I'm planning on getting two more for another house.

*update*

The fan is still going strong about a year later, and I have been pleased with how cool the house stayed even on hot days this summer. A comment to one of the other reviews did raise a question in my mind: how can the fan really provide 850cfm performance from 20W of power, when other AC fans rated at 1200cfm consume so much more? It would be nice to see an independent verification of the performance claims.

The same comment mentioned that a simple turbine roof vent provides better performance (in windy areas) than this unit, at far less cost. That would be a good alternative, except that I don't like the look of the turbine fan on anything other than ag or industrial buildings. Ah, the price of vanity...

Our crawl space is very difficult to move around, so the price of installing wire to power a traditional exhaust fan was prohibitive. So, solar was a practical choice.
Pros: Installation directions were very clear and easy to follow. Worked the moment the sun hit the panel (so keep it covered until fully installed!).
Cons: Not as powerful an exhaust as traditional fans, but does the job.
Hints: Strongly advise getting the thermostat.

Having been a heating & air conditioning contractor, I knew the value of attic exhaust fans: a properly sized fan can keep an attic at least 20 degrees cooler than a gravity-ventilated attic. And if your attic is cooler, your house will stay cooler. The problem is that most 120-volt attic exhaust fans are really noisy. The noise from gable-mounted fans isn't too obnoxious, but the noise from roof-mounted fans can drive you up the wall. (The roof membrane acts as a drum and amplifies both the motor vibrations and the 60-cycle hum.) IN CONTRAST, NATURAL LIGHT'S SOLAR OPERATED DC MOTOR IS SO QUIET, YOU HAVE TO GET RIGHT NEXT TO IT TO EVEN HEAR IT!

I'm very impressed with this product. It is well made, it has good installation instructions, it comes with an exceptional warranty, and if you need to talk to the manufacturer for any reason, Natural Light is very responsive.

The optional thermostat is worthwhile: it prevents the fan from running on a sunny (but cold) winter day.

Addendum, September 2010:

One of the two units failed horribly. It was making this awful squealing noise that pervaded the entire neighborhood. It was louder outside than inside so it took me a couple of days to realize it was coming from my house (I am typically not traveling in the neighborhood while the sun is shining except in a car).

The motor bearings had failed. I called BFM and they sent me a new motor - which bore absolutely no relationship to my old one other than it was kind of round. The bracket did not fit and the holes didnt even line up. I asked for more support and BFM ignored me, then told me to call Natural Light systems (the mfr). To be honest I was surprised BFM did not tell me to talk to the MFR in the first place, but once they accepted paternity of the problem, they should try to solve it.

The mfr said that my unit was an early one and the motors they used back then had a high failure rate, so they had switched suppliers, but it was up to me to make it work.

I had to drill out the holes in the bracket to make them wider to fit the old screws. And I had to do it hunched over in a dark dusty attic.

NOTE: the screws are loose in the holes and will pop out and fall off your roof when you try to attach them from inside the attic, you will either need someone outside (with an allen wrench handy) to hold them, or maybe superglue them in place. Fortunately they sent two more screws :-), and had the foresight to list in "instructions" what size of tools you need (that was nice of them). I guess I will have to try the superglue - most of my friends are too old for me to suggest them climbing on my roof, and my attic is unique in its configuration and requires an acrobat or at least someone who wont sue me if they fall to get around in (I fit the latter category not the former).

But I believe they should simply have given me an adjustable bracket that fits the old unit, the impression I got on the phone was that the failure rate on the older motors was very high so they should own up. On the other hand they didnt give me any crap about needing to prove my purchase (which shouldnt matter since none exist that are old enough to be out of warranty).

NOTE: I have put a remote temperature sensor in the attic which I record on my laptop computer and plot to compare with outside temperature (engineers find amusement in different places than most people) and can see -NO- change whatsoever between attic temperature with fan running and fan not running.

---------------

I have a split-level house (2 unconnected attics). I bought 2 of these units 3 years ago, 1 for each attic, and had them installed when my roof was replaced. They are amazing. I just went up there (sunny afternoon) and the one which faces south was moving a ton of (hot) air. The other one (faces west, sun not there yet) was doing well.

I have no evidence whatsoever if they actually save me any money, as I replaced the roof and then the A/C in the following year, so I have too many changes for a "before/after" comparison. Plus I have very thick attic insulation, so I suspect my actual savings may be minimal. But seeing them makes me feel better, kind of a placebo effect.

They come in a "doesnt match anything" grey color. I spray painted them brown (cover the solar panels first!) with rustoleum - 2 coats and it is still pretty good in year 3. Next year I may go up there and touch them up, from up close a couple of spots were showing greyish.

The units themselves are very sturdily made. Heavy aluminum chassis. I have the 10W units I dont believe the 20W was available back then. Very quiet, cant hear it unless right next to it. One of them had a bent fan blade when it arrived but a single call to BFM got a new one sent with no questions asked (well, other than "where do we ship it to?"...)

I like playing with solar panels and these panels seem high quality; they produce more power than any of the cheap ones of similar size which I have seen from Harbor Freight.

I also have traditional "passive" roof vents and I suspect my fans are drawing air backwards through them, so I am thinking about blocking the passive roof vents in order that the solar fan will draw the air up through the eaves vents which would cool the attic better.

I have the (optional) thermostats on the units, but I am thinking about removing them so that in the winter it will draw moisture (from bathroom fans and stuff) out of the attic as well.

I would absolutely, positively recommend these over the traditional wired A/C units. I cant even imagine what the 20W units must do; people must have to be clean birds and pets out of their intakes all the time.

I am in Dallas, TX and installed it on my roof about 10 days ago. The installation cost was just $75 (done by southern roofing). By 27th May the temperature has already crossed 90 degrees few days so far. I am pleased with its quite operation and simplicity to install. My attic size is about 1300-1400 sqft. Around 5:00 PM at 95 degree outside temperature my attic temperature is only 100 degree, without this fan the attic temperature would have been at 135 degree. The fan blade spins even when not so bright sunny although not at the highest speed. For the best result place it on the west side of your roof. For best performance, I believe 20 watts fan will work even better. I bought the thermostat switch also but probably there is no need for it in summer in Dallas. The attic temperature is always above 80 degree so thermal switch is useless unless temperature falls below 70 degree. My advice will be to save $25 for the thermal switch and instead spend more money for 20 watts fan. In winter from inside of the attic you can just disconnect the cord supplying the power to the motor so it will stop operating then attach it back during the summer so you don't really need the thermal switch.

Overall it is doing its job what it was supposed to do. I'll highly recommend this product.

You can find some cheaper fan specially electric powered in the market but my roofer said most of the electric fan motor burns out in just few years so I chose this sloar powered which should have longer life as it runs using DC powered motor.

I'll probably update this post again in July when temperature crosses 100 degree mark.

Just have it installed on one of my attics - running very quite and spinning fast. I have not measured the temperature before and after - but the difference is obvious - before it was VERY hot, now only slightly hotter than room temperature.

The unit is built with quality - very sturdy. I had a concern that it is not as efficient as an electrical one in pumping out hot air - but it turns out to spin very fast even with a 10W fan. I had another concern of water leaking, but the unit has a pretty big "apron" and a dome cover so it should not be a problem.

Now I am thinking to install one more above another attic I have.

I installed this fan on my flat (slight slope) built up tar roof on my 100 yr old rowhome in DC. It was as easy to install as it says, only about 30 minutes with a rip saw, screw gun, and some adhesive. I did add some additional roof flashing to be safe as my roof not very level. Before install our thermostat on the first floor was set at 74 and the temp in our second floor bedroom was usually around 80. After the install, without changing the thermostat, the temp in our second floor bedroom is usually around 77. Of course, I also had the roof coated with an aluminum reflective paint (as opposed to black tar) so that also had a positive affect. I did get the thermostat for the fan also as I didn't want to climb up on the roof every Spring to turn the fan on and every Fall to turn it off. It runs continuously otherwise.

It took my husband and a friend about 45 minutes to install. We watched the video on how to intall one online first. When we checked the attic we immediately noticed a dramatic increase in the air flow. We've had a couple of storms with small hail and there is no damage to the solar panel that we could see. After the sun goes down, there has been an increase in the temperature inside the house as the fan is no longer working. We thought it was a little expensive but I didn't want to pay the utility companies for an electric one. We've been trying to find ways to become less dependent on goverment utilities that is within our means. We don't know yet if it will help to lower our electric bills as our hot summer is just beginning. We are hopeful our A/C won't go on as often. Now someone needs to harness the power in a battery form so the unit will run all night or when it is cloudy and keep the attic cooler.

This product was as easy to install as any type of non powered or basic roof vent. Just take special precaution to make sure your under the shingles on the top half of the mounting ring, and over the shingles on the bottom half to ensure proper water shed w' no leaks. this unit is whisper quiet, extremely effective and does a wonderful job.. i would maybe get the 20 amp fan next time, but am impressed by the 10 amp i purchased. the only thing i didnt account for is that the currently passes over my house be around 7:00pm far enough to not get very good direct sunlight after that time. Thus the solar is no help any longer. so i am trying to figure out a battery backup to continue to take the edge off the temp on those extra hot days and nights. something that can possibly power that fan for another few hrs to keep up with the hot nights. i can tell shortly after the unit shuts off as my house temp rises. it is actually hotter at around 8-9pm than at the warmest point of the afternoon if i dont have the a/c running because the fan does such a good job at cooling the attic. the solar fan does a superb job at lifting that hot, stale air out of the attic. worth every penny.