Not necessarily better as much is the different coatings are more climate specific.

If you have summertime cooling issues, the Low-e 3 would be a better choice for further controlling the sun's radiant energy. You are a pretty mixed Climate in San Francisco, but if you don't mind the slightly darker glass with the Low-e 3, you will be fine using it.

I would think that San Francisco is a climate better suited to Low-E2. Even West facing windows there don’t get the kind of radiant heat that would necessitate Low-E3. As WoW said though, if you’re ok with slightly darker glass (less interior light) Low-E3 is fine.

Title 24 is code in California and you should start there as to whether you are required to use 2 or 3. From what you have said of your situation, 2 is probably okay but you should at least verify it. Check with your building department.

If I can resurrect this thread, Im buying Marvin and I have a Marvin rep that's trying to talk me out of every possible upgrade - triple pane, low e3 - I can't tell if he is the most honest sales guy ever or just wants me to get lost :)

I'm in Toronto, and was thinking low e2 for my northern windows and low e3 for my southern windows. Or should I do low e3 for all?

friedajune is spot on about the Low-e 3 vs. Low-e 2. You definitely do not want to block anymore of the sun's free energy in a double pane window than does standard Low-e in your climate.

Whether you upgrade to triple vs. double really depends on the cost and how efficient a structure you are trying to build.

Sorry for bumping such an old thread.

Does this information still apply in 2023? For more mild / colder areas like in san francisco, low-e 2 will be better since we want the warmth of the sun to enter into the home.

I've driven past some nicely renovated homes in SF but their windows are extremely tinted and green, and can only assume they chose low-e 3. Unsure why since its pretty cold here.