I'm building my house in SW FL right now. We have our back facing south and have a 9' lanai on the rear. I am getting nice filtered light in the living/dining room. It's a single room deep so the north side gets light too, but the north side has the roof eaves. All roof eaves in my house are 32" wide.

Upstairs where my studio doors to the balcony are, the light is a bit more direct, but it's not overwhelming.

This is a picture of my living room looking from the kitchen area. The lanai (south) is to the left in this photo

Here is the same rooms looking from the living room towards the kitchen/dining area.

Thanks, cp... and I wish you all the best with the build - it looks like it is coming along beautifully!

Do you know if any direct rays come in from your south side... an effect like this... I'm hoping to have some rays of light in the living area.

Beach Style Living Room · More Info

Do you know if any direct rays come in from your south side... an effect like this... I'm hoping to have some rays of light in the living area.

Can't answer as my house didn't have a roof before end of April/beginning of May. I say that because summer sun is higher in the sky so the south facing rays would be blocked because of the lanai and our wide eaves.

I'm thinking that in the winter when the sun is lower in the sky we might get some more direct sun rays.

And leave it to Mark to be direct in getting his point across. Of course he's right. When it's 90 degrees outside, you don't want the sun shining in.

How much light gets past a porch and into a house is not only a function of how deep the porch is but also a function of how tall the ceilings are. A 9' or 10' ceiling is going to be capable of letting in a lot more light than an 8' one. And then of course who says the ceiling height of the porch has to be the same height of the interior ceiling?

From personal experience I don't think it will effect it that much if you have decent ceiling heights. Here's one of my own houses (yes it's different when you're spending your own money!) with a porch and the interior was filled with light.

If you want to do some trig, you can calculate this. You'll need your time zone, latitude, longitude, height of your windows and depth of your eaves/porch. The calculator below gives solar elevation angle [and azimuth angle*] for various times of day:

http://keisan.casio.com/exec/system/1224682331

It gets a little more complicated if you want to include the travel path of the sun from east to west, but you can get a general idea without that. If you want to include it [use the calculator above*], and I find this website to be helpful to visualize that angle throughout the day:

http://suncalc.net/#/40.7128,-74.0059,10/2017.06.29/08:43

I understand wanting those patches of sunlight on the floor. Although, I live in Canada and our average high for July and August in my town is about room temperature.

[*edited to add that I just noticed the first calculator includes azimuth angle. I still like the visual representation of the second though, so I've left it here]

Actually....maybe one of the resident architects can answer if this is the sort of calculation your architect should be able to provide for you. I'm guessing it must be part of the curriculum, right?

Yes, if you talk with your architect about this, s/he can easily do the math and show you how much direct light will penetrate into the interiors. Don't forget "bounce" light, resulting from the sun "bouncing" off the deck/porch and up into the house.

It's important to remember that in summer (that's when it's really, really hot) the sun is highest in the sky and easily blocked from strong direct light into the interiors causing the air conditioner to work overtime and your utility bills to skyrocket. In the winter, however, you may want some direct sunlight to help warm the house and reduce heating expenses (you do heat in winter don't you?).

In other words, porches, arbors, pergolas and the like can easily be designed to work with the sun in both summer and winter. It's the basis for passive solar design strategies! :-)

My south facing porch in under the main roof and eaves overhang a bit. We have cold winters in Maryland so it is a great bonus to have the lower sun angle heat that exterior space, almost tolerable to be outside in the cold months. In the Summer the sun is more from the east and over head so it doesn't get overly hot and is nicely shaded. The interior light is boring midday no matter the season, but the lovely view more than makes up for it!

don't discount the bounce light, as Virgil calls it. My home is designed so that the front facing south overhang allows ZERO direct sun rays to enter the house in the summer. at the autumnal equinox, the light starts coming directly in the windows.

However, the house is amazingly light / bright with the large window openings, the high shading structure overhands and the light colored concrete outside. And the HVAC won't have to fight the intense summer sun.

Thanks, All! Your comments were really helpful for me to think through the impacts. We met with the architect today and loved it - he's great. What a difference it makes to trust one's architect... we are going with his porch addition. He even had an article out for me about Florida sunshine. ;) We'll add clerestory windows to help with direct sun in winter.
Now just have to figure out where to cut h/c square footage... our 1500 sq feet morphed into 1900, so we have a sketch to look at for the weekend to contemplate cuts and changes. (Might post a new thread later in case anyone has a magic wand handy.)
Thanks again!

The higher your window heads, the deeper the penetration of direct and indirect light. High ceilings and high windows hears always maximize available natural light.