WCS Hardware Guide – The REC365W Alpha Black Module

Welcome all to another installment of our Whaling City Solar Hardware Guide. We believe that sharing our collective knowledge with you our prospective customers allows us to talk to each other in the same language. Doesn’t matter if it’s a solar module, an inverter, a racking component or an electrical safety device – if you’ve never heard of it, we’re here to change that before it goes on your house for 25+ years. Found something on the internet you’re interested in but we haven’t covered yet? Please write to us and ask!

Today’s subject: A phenomenal 365W residential solar module made by REC Solar.

Our views on solar modules as a whole

Solar “panels” (used interchangeably with the term “modules”) are the first thing we all see when we look at a solar installation, so it makes sense that they get the lion share of attention. They also have a lot of mystery associated with them because there are so many installation panels selling so many different brands at so many different prices it would make anyone’s head spin. In reality they are just stationary sheets of glass and silicon up on the roof, layered in slightly different configurations depending on the manufacturer to achieve certain characteristics. To this end, we strongly encourage you not to view the solar panels you choose for your home as “good panels” vs. “bad panels” but instead ask why the panels characteristics (including price!) are the right fit for your home.

To help sort these characteristics out for you comparing models, we’re going to follow a basic template describing each solar panel we cover. If you’ve already read our template text below, please feel free to scroll straight down to the hardware review!

  • Performance – Wattage, Efficiency and Environment
    • Wattage per panel: Every model has a nameplate rating (almost always the number in it’s name) that shows the rate of DC power they can generate at an universally agreed upon set of temperature and sunlight conditions. Meaning a 360W panel won’t necessarily make exactly 360 watts on your home, but it will make proportionally more power than a 310W panel in the same location. Here in 2021 we have access to dozens of choices in the US market ranging from 300W up to 450W, all with different physical footprints, efficiencies, and prices. Wattage is important but certainly not king!
    • Efficiency: Historically non-distinguishable to wattage per panel, however that’s changed recently with certain manufactures finding success with larger non-standard footprints. A larger footprint panel may look better at first with a higher wattage, but remember you’ll be able to fit less on the roof! Efficiency lets us compare this new breed of panels on fair ground, but be warned high efficiency panels can sometimes be more expensive than the value of extra electricity they produce. Efficiencies currently range from about 17%-22%.
    • Environment: Notice how most high power devices like laptops always have a cooling fan running? Electronics typically perform better in low temp environments, and solar panels are no different. Solar panels will actual produce the more power on a long cold sunny day than a hot one. How much more? There’s a temperature coefficient published with each solar panel that shows us in %/º C (sometimes %/º K – which is the same thing). Temperature coefficients range from about -.50%/º C to -.20%/º C the lower the better.
  • Manufacturers Warranty – Materials & Performance
    • Materials: A solar panel’s material warranty insurance covers the interior of the panel itself and can be claimed for manufacturing defects, environmental issues, premature wear and tear. We’ve been doing this a long time and we can say confidently that it by far your most likely scenario is that your panels will never have a warranty claim. Understand also that in the rare case one panel does require replacement, the rest of the system will still be operating in the meantime. We will not install a solar panel without a minimum guarantee of 10 years without failing.
    • Performance: Due to normal electronics aging the amount of electricity a solar panel produces declines slightly every year, but not by much. The manufacturers define an acceptable threshold for how much is too much. Like the materials warranties, we can count on one hand the number of panels that have ever exceeded this threshold. However we do feel like a better performance warranty is indicative of overall craftmanship of the panels and predicts even lower degradation behavior. We will never install a solar panel that is not backed by a minimum solar panel’s performance warranty guaranteeing 90% production at 10 years and 80% at 25 years.
  • Price
    • The direct price per panel that Whaling City Solar pays our supply chain vendors. We encourage you to compare our prices to the online “wholesale shops” because we put a lot of work into buying each model number at bottom dollar to pass those savings on to you. Remember that the panels themselves are just one part of whole installation, accounting for about 15-20% of the total installation cost. Choosing a value focused brand over a efficiency focused brand can result anywhere from a $1000-$4000 swing in the overall cost of the system.
  • Aesthetics and other features
    • Aesthetics are a variable that may matter a ton or very little to you depending on the placement of your panels on the house. You own opinion matters more than ours, but we can show some pics to help you get a feel for what they may look like on your home. For street facing residences and businesses, we will always default to a black cell, black frame, black back sheet variety of panel from your brand of choice. Other features may include some fancy wiring for shade mitigation, additional rear frame bars, etc. features that don’t necessarily affect the main performance variables discussed above, but have some benefits we feel are worth mentioning.
  • Conclusion
    • Our unfiltered thoughts on why and where we would recommend these panels.

Model # REC365AA BLACK – Spec Sheet


  • Wattage per Panel: 365W
    365W is in the top tier wattage class for a residential panel as of the writing of this article in Jan 2021. An array of QTY:20 REC365AA Black’s would create a 7.3kW solar system (that’s just 20 x 365W for those curious) that would subtract about $160/month off of your electric bill, plus an additional $63/month dollar SMART incentive check.
  • Panel Efficiency: 20.9%
    The reason this solar module can reach such a high efficiency level is due to it’s solar cells being heterojunction – truly the latest and greater solar panel technology to hit the industry. If you want a very technical review of this solar panel, check this article out. For a shorter version though – in our case, hetero means different types of solar cells, while junction talks about where these solar cells meet and deliver electricity. In the case of this ALPHA panel – a standard silicon solar cell has an added thin layer of a different type of silicon that boosts it’s production. More power coming out of the same amount of space is what we’re always chasing!
  • Temperature Coefficient: -0.26%/°C
    Another reason we love this panel is it’s ability to keep pushing out max power on sunny days. On a hot August day at 35 °C (95 °F) we would anticipate about 2.6% losses due to temperature, which is one of the lowest numbers on the market right now.

Aesthetics and other features

  • Aesthetics – True Black
    • Color wise, the REC370AA BLACK is about as flat a black as we’ve seen – and really, it’s Solaria and REC setting the industry standard for this new generation that look like OLED TV’s up there. We lay them on low rails a few inches off your shingles so they keep a nice tight profile from the street. Front of the house? You’ll have neighbors asking about where you got these panels for sure.
  • Panel Level Shade Mitigation


    • The panel’s wiring also helps mitigate losses due to shading . All solar panels get some shade, whether it’s from a passing cloud or a fixed obstruction like a tree/chimney. Microinverters or optimizers help mitigate some of that shade loss, but the REC370AA BLACK is wired in two sections to keep half of the panel online while the other half is shaded.

Fun Fact: This is the first .GIF we figured out how to embed on our website! Monumental day.

  • Reduced Flexion


    • REC claims internal testing standards that are three times as severe as industry standards. They are considered to be very reliable in extreme environmental conditions – like, say, snowy regions. The product quality and reliability are backed by low claims rate – out of 4 million panels manufactured each year, about 400 come back as product warranty claims. This could be attributed to the additional two frame bars on the rear of the panel preventing small cracks (known in industry as microfractures) that increase the degradation rate.


  • $263 per panel ($.72/W)

As with all of Whaling City Solar’s SeeThru SolarTM pricing, we pass the direct warehouse panel pricing direct to you homeowner. Including transportation costs to the house, these REC365AA BLACK panel cost ~$263ea ($.72/W) as of the writing of this article. We find that to be a very competitive price compared to others in their wattage class. A full installation using these panels would cost around $2.90-$3.20/W depending on the overall size of the system. If this pricing format is confusing right now, please do yourself a favor and understand how our SeeThru SolarTM pricing works!


  • Material Warranty: 25 Years
    • The REC group really stands by their work, offering a full 25 Year material warranty on the panel being free from defects. Not only that, if the panels needs to be replaced – they’ll help pay for the labor to replace them.
  • Performance Warranty: -0.25%/YR
    • This is an astonishing number and the lowest we see on the market right now. This means, after 25 years of life – these panels will be generating electricity at 92% of their original capacity or they’ll replace the units.


Lots to love here, so much so that it’s our default spec when our engineers see an appropriate use for a high efficiency panel. As engineers, we appreciate the robustness of the backing bars for our snow loads up here in MA, and the warranty gives everyone a better peace of mind, even if it’s unlikely to be needed. We also love the price point compared to other high efficiency panels such as the Sunpower, LG or Panasonic brands.

If you have a high electric bill coupled with a roof space that’s visible from the street or your backyard entertaining area, we would likely recommend the REC365AA BLACK as a starting point and take the conversation from there. That’s about 40% houses we visit, so you won’t be alone. Is the REC365AA BLACK the right panel for you this year? Please don’t hesitate to reach out below for a free no hassle quote for your own home!

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