That is a good question, the sunroom opens up to 70% of our living space in one great room it includes kitchen, dining room, living room/family room. It is where we usually are if we are not in bed!! The thermostat is in this room. Currently the opening is huge, nine feet, I am closing this off with french doors and casement winds. I am just in the initial stages of weaning this house off natural gas. A furnace upgrade will come come in several years. Right now I am focused on sealing this sunspace and spent the weekend begining to seal up the ducs and adding insulation. The gas fireplace will be the next big issue to address, it lies in the middle of the living space and has a brick chimmney going up the middle of the building. Your questions "A and B" will be determined by how clever (or if) I can get a fan blowing out the ceiling in the summer. The larger deciduous trees do shade southwest and west in summer already. To get the air in I hope to rig the return to my furnace on the sunroom roof into the living space. I have yet to figure out the best way to do this. So with a fireplace insert, insulation and sealing, and a functional passive solar space I would be thrilled to cut my gas bills in half.

So your GC thinks that removing some of the covered porch in the back will be negligible in light gain? I would disagree. It would help a measurable amount with light gain in that portion of the house. As far as energy consequences, I agree with negligible. As for Passive Solar input on the front, your current design will have close to zero benefit. South facing entrances on passive solar designs are the most challenging orientation to design for due to the need to eliminate shading (covered entrances or porches). If youre serious about passive solar (free heating) then you could eliminate the jog in the family room, eliminate the front covered porch and increase the amount of glazing on the front of your house. You could leave a small amount of covered porch just at the front door, perhaps making it with a nicer finish like timber frame to compensate for the sacrifice in the bigger covered porch aesthetics. The Kitchen, office and covered entry will make this challenging but could have some measurable benefits.

I am interested in building a trellis over three south facing windows in order to reduce heating in the house. The trellis will support small vines that have leaves during the summer including jasmine and a light grape vine. I am looking for ideas on materials and design. The tops of the windows are ten feet from ground level. The house does have vinyl siding so I know that attaching a trellis can be tricky.

Where in Canada? I live in Washington state and my main living areas all have huge south-facing windows. My kitchen also has an east window. I don't know if my house was built perfectly for passive solar heating intentionally or if it was a lucky accident. Since the house was built in 1949 before people put much thought into it, I'm guessing the latter. During the summer, the angle of the sun is much higher in the sky. So we get a lot of light into those south-facing windows but virtually no direct sun due to the wide eaves on the outside. (I think they're 3-feet). The only time we get any direct sun in the warmer months is for a short time in the morning and the evening when things are cooler so it's not a heat problem. Of course, we don't get a lot of real hot weather up north here anyway. But even on the rare days temperatures reach into the upper 80's and low 90's, the eaves keep the house from overheating and it's cooler in the house. We have no AC and I can't imagine we would ever need it. During the winter, the angle of the sun is lower. During those cooler months we do get direct sun but our area has a lot of overcast days (on the coast) so the sun is obscured by cloud cover. We still notice some warmth from the sun but it's not real strong. We can lower our thermostat a tad and I do know our heating bills are generally lower than many of our friends even if our house sizes are similar. So we are getting some solar advantage. On clear, sunny days in the winter, we often don't even need to have the heat on in our house, even if the temperatures have dropped into the 30's (cold for our area, normal winter temps are in the 40's). We might only need supplemental heat for a short time in the morning and then again in the evening. Sunny winter days are the only times I think we should probably have window treatments. The rest of the year, the light is indirect enough where window treatments aren't needed. Anyway, this is a long story to illustrate that south-facing windows don't necessarily mean your house will overheat. It really depends on more factors than just the direction. I think sun angle and depth of eaves play a big factor. At least in my experience in my own home.