Natural Light Solar Attic Fan Fire Safety Switch Brand Only

SUMMARY: It was really hard finding any actual numbers on the temperature decrease from an attic fan installation. Most people would write something like "it definitely FEELS better" but that was too subjective. So I created this review with some actual before-and-after numbers so that one can be better informed about a fan's potential temperature reduction. This fan cooled my attic by an average of 6 degrees (may not sound like much of a drop but keep reading for the reasons why). Note that my attic temps, prior to installing the fan, weren't as hot as others have reported (I've read that some people's attics get to 140+ degrees!). I guess my attic's temp wasn't that high after all. The difference between my attic's daily peak temp and the outdoor's peak temp, was in fact lowered after the fan was installed. All of my "geeky" details are below along with before and after temp data I charted.NOTES & MY LEARNINGS FIRST: I live in an 18 year old, two story 3300 SF home with gray, flat CONCRETE tiles on the roof, in Cupertino, CA (zip 95014). My attic's volume is ~1500 SF. Installation was done in July '16 by myself. Fan comes on around 10-11am daily when the attic temp reaches 80 degrees. After sunset, it intermittently cycles for 15 mins every hour until the wee hours of the morning and the attic's temp drops to the 60s overnight. Once the temp drops to 77 degrees, the thermostat no longer has the fan cycle. Relative humidity in our attic ranges from 20% to 30% depending on the time of day. Attic temp peaks between 4-5pm daily (July/Aug). If I keep the attic access door in our hallway open and open up the upstairs windows all day, I can drop the attic's daily peak temperature by another 3 degrees, which is how I know our attic can benefit from more intake vents.Through measuring my attic's temperature hourly throughout the day, I confirmed that my attic remains hot for hours after the sun sets. This may be true for most attics. Here in the Cupertino, we don't have that many days above 95 degrees, but our 2nd story bedrooms can remain hot on the 95+ degrees hottest days until 10pm. In the pictures are the net temperature differences in my attic before and after the fan installation. Before that though, here's what I did to modify my solar fan to continue cooling after sunset...This fan is great, but I wanted more!Natural Light's 36 watt solar attic fan (model SAF36B-FL) doesn't have a feature that I really wanted....a way to have it continue cooling my attic even after the sun goes down. (I thought I'd have to make my own circuitry to do that.) I really like that unique feature of the US Sunlight fans using their optional Solar Control (model #SC20), so I bought both and made some easy wiring modifications to make them work together. I preferred the Natural Light fan due to its high Amazon rating but also wanted the other company's "cool" functionality (see what I did there?) of their Solar Control. It switches between solar power and AC power depending on sunlight availability (after sun sets), has a remote control for the fan (always on or thermostat controlled), and a remote LCD display showing attic temp/humidity. At first, I wasn't sure if they'd work together, but after doing it, I now know it works and I have the best of both worlds...it's now perfect for my needs! =) I'll share how I did it:Re-wire the fan so that the Solar Control acts like a thermostat. Instead of having the red/black wires from the fan's solar panel going straight to the motor, I have them going to the Solar Control instead. The wiring connectors had to be cut and spliced (cut off the spade plugs and solder the wires on to the Solar Control's cables), but that's all it took! 10 mins and done!Here are some things that weren't documented anywhere but I discovered them during my project. They'll help you should you want to do this too:* The Natural Light 35 watt solar attic fan's solar panel's output is 20 volts DC. With full sunlight, the fan motor draws 1.8 amps. (36 watts = 20 VDC x 1.8 amps)* I purposefully bought the bigger model fan (36 watts) since my attic has multiple levels/pockets of air, figuring I'm less likely to have buyer's remorse if the purchased fan is too strong. I can easily slow down the fan speed by covering up a portion of the solar panel. Slowing down the motor by shading a small portion of the solar panel works perfectly.* It turns out that covering up only ~5% of the panel from sunlight results in the fan RPM slowing down to roughly 2/3 speed....perfect if one wants to "dial in" the right amount of attic suction without creating a negative pressure in there. The voltage/current draw is reduced accordingly.* The Solar Control outputs 18 VDC to the fan, so I had a pretty good sense pre-purchase that they'd work together despite US Sunlight telling me that their device works only with their fans (both devices' operating voltages are within acceptable/compatible range of each other). Whether at the full 20 VDC output of the panels or at a reduced voltage, the two work fine together.TEMPERATURE DIFFERENCES BEFORE AND AFTER THE FAN INSTALLATION:I recorded the daily PEAK attic and outside temperatures so that I could see how much the fan is helping. I wanted to know the "baseline" temperature before so that I could justify the cost and effort. Attached is a screen shot of the chart I created, but basically, the fan dropped my attic temperature by an average of 6 degrees on days that had a varied outside temperature of 76 to 91 degrees. I'm happy that the fan helps keep our attic cooler, but I have to say that it would have been hard to know for sure w/out taking before-and-after measurements.I'm concluding that some online reviews of "...house feels cooler..." may contain some wishful thinking (avoiding post purchase cognitive dissonance--there, I used that term I learned way back in college!) Your mileage may vary so don't expect a single fan installation to make your house cooler necessarily. I do not regret buying and installing this fan, because I learned A TON about attics, roofs, temp patterns, etc from the experience.I should note that prior to installing this fan, my attic did not have ANY exhaust vents--a pro roofer discovered this while giving me a fan estimate and told me the builder probably actually forgot! My attic temp drop would be 9 degrees (additional 3 degrees drop) if my attic had adequate intake vents.

This is a simple thermal fuse. If it senses a fire it blows. This cuts the solar vent motor off. The idea is simple...should the house experience a fire during a hot day, the fan will cut off and not make matters worse by drawing air. Frankly, it's probably not necessary and we hope it is never used. We bought it simply because it will not impede the operation of the solar vent in any way, yet might help to save the day in certain circumstances. This will fit on a Broan attic fan. It will also fit, in series, with the Natural Light temperature switch, which we also bought here on Amazon. One would be hard pressed to make one of these up from components and save much money.

Fantastic product. Relatively easy install and ships with necessary screws and a tube of sealant. I ordered the thermostat and fire switch as well and they all snap together perfectly. I bought two total and they both kicked into high gear immediately and the air they pull is fantastic! Tremendous relief in attic temp with at least a 20-30 degree drop in temp. I plan on buying a third!

Small price to pay to avoid more damage if the unthinkable happens.

Easy to install.

The installation of this switch is great - there is no way to hook it up wrong - the spade connectors are arranged to plug it in and it is ready to go. Now I hope this switch is never used but it truly eases ones mind knowing it is there in the event of a fire.

save a firefighters life and lessen damage to your house in a fire. make sure you have this for solar attic fans.

Functional and works well.