I live in Montreal, Quebec, 45.5017° N, in the second floor of a duplex. The back balconies are oriented at 224 degrees SW and my balcony is at 59m of elevation. Here's where it gets interesting. The balcony is 1m27 deep and I would like to extend it by about 46cm, 18in. It is 1m94 wide, actually double that as my next door upstairs neighbour wants to do the same at the same time. I would like to know how many minutes of sunlight will be lost for the downstairs neighbours who each have a window and half-windowed door under the balcony which almost spans the 1m94 on each side. It's not such a big deal in the summer as additional shading would be a good thing but in the winter, the only sunlight in the kitchen is from the two windows, the real one and the upper part of the door. If it would be a matter of 10 minutes of sunlight for the extra 46cm, it won't be such a problem but if it's an hour or two, that would be really bad and cause us to rethink the project.
Thanks for any help anyone could give me. I know I'm supposed to use sine, cosine, tangent, all that stuff I learned in high school but I absolutely don't know where to start.
Have you consulted your local building official? Balcony projections often are a factor of limiting distance maximums and the extra length of construction might cause quite a bit more headache than just sunlight deprivation. It's likely that you will not be allowed to enter the construction and even if you were, if I were you're downstairs neighbor, you'd hear very quickly from my lawyer.
Do you have an architect and structural engineer on board? Probably best to ask them, and pay for their time, than take a short cut with an attempt to get free advice.
@Olaf Dead Nutter_, I'm finding the learning curve for SketchUp way longer than 20 minutes but thank you, think I'll try to become more proficient just for the fun of it before the 30 day trial is up. @Non Sequitur, there are others on the street with the same building who have recently done the same thing so the local building office has approved it (for them). I've spoken to them about the daylight issue but as the two people concerned are the owners of the entire duplex, they accepted the lessening of sunlight because they extended their lower decks at the same time. It was not a factor for them.
Bottom line, as my contractor has a time limitation and winter is fast approaching, there will be no extension. I'm trying to sell so the next person can build it out if they want to. Thanks for the suggestions, all.
This site (or others like it) will give you the solar angle at your location, at any date and time you specify: http://www.susdesign.com/sunangle/. You can draw the balcony extension to scale, plot a line that matches the angle of the sun, say once every week or two, and put together a spreadsheet that will graph the amount that the window is shaded. It will be a sine curve.
The sun is at its maximum angle above the horizon at noon on June 21, about 68° for your location. At its lowest, on Dec. 21, it's 21° above the horizon at noon.
Alternatively, the PHPP (Passive House Planning Package) energy modeling program does what you are looking for, and includes adjustments for climatic conditions. It's not inexpensive or easy to learn, but it is quite accurate.
Oct 7, 16 4:02 pm ·
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Need to calculate sunlight lost after balcony extension
I live in Montreal, Quebec, 45.5017° N, in the second floor of a duplex. The back balconies are oriented at 224 degrees SW and my balcony is at 59m of elevation. Here's where it gets interesting. The balcony is 1m27 deep and I would like to extend it by about 46cm, 18in. It is 1m94 wide, actually double that as my next door upstairs neighbour wants to do the same at the same time. I would like to know how many minutes of sunlight will be lost for the downstairs neighbours who each have a window and half-windowed door under the balcony which almost spans the 1m94 on each side. It's not such a big deal in the summer as additional shading would be a good thing but in the winter, the only sunlight in the kitchen is from the two windows, the real one and the upper part of the door. If it would be a matter of 10 minutes of sunlight for the extra 46cm, it won't be such a problem but if it's an hour or two, that would be really bad and cause us to rethink the project.
Thanks for any help anyone could give me. I know I'm supposed to use sine, cosine, tangent, all that stuff I learned in high school but I absolutely don't know where to start.
Do you have an architect and structural engineer on board? Probably best to ask them, and pay for their time, than take a short cut with an attempt to get free advice.
use computer software, maybe sketchup can do this? i know 3dsmax could
In Montreal, this is what, 300 days of the year?
The other 65 days they will lose 0 minutes of indirect sunlight.
They will lose 0 minutes of direct sun when they are sleeping. 0 minutes while they are at work. 0 min on vacation & also while at church.
Therefore, total loss of 10 min a year.
^ xDDD
@Olaf Dead Nutter_, I'm finding the learning curve for SketchUp way longer than 20 minutes but thank you, think I'll try to become more proficient just for the fun of it before the 30 day trial is up. @Non Sequitur, there are others on the street with the same building who have recently done the same thing so the local building office has approved it (for them). I've spoken to them about the daylight issue but as the two people concerned are the owners of the entire duplex, they accepted the lessening of sunlight because they extended their lower decks at the same time. It was not a factor for them.
Bottom line, as my contractor has a time limitation and winter is fast approaching, there will be no extension. I'm trying to sell so the next person can build it out if they want to. Thanks for the suggestions, all.
This site (or others like it) will give you the solar angle at your location, at any date and time you specify: http://www.susdesign.com/sunangle/. You can draw the balcony extension to scale, plot a line that matches the angle of the sun, say once every week or two, and put together a spreadsheet that will graph the amount that the window is shaded. It will be a sine curve.
The sun is at its maximum angle above the horizon at noon on June 21, about 68° for your location. At its lowest, on Dec. 21, it's 21° above the horizon at noon.
Alternatively, the PHPP (Passive House Planning Package) energy modeling program does what you are looking for, and includes adjustments for climatic conditions. It's not inexpensive or easy to learn, but it is quite accurate.
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