First, what do you need light for? Do you do paperwork? Is your desk in your window? You'll be getting afternoon sun. I'm recommending LED lighting to people, but Fred says it has a way to go in brightness and affordability. I recommend sky tubes to homeowners. I've had 2 in one of my houses.

@Lee Rohrbough, the picture you posted is one fantastic stylish bathroom, absolutely love the whole design but especially the tiles. I have already chosen travatine tiles for my new bathroom so can't change that but I have a hint of a tile colour called Emperador as a feature in the shower and although your tiles aren't Emperador, it sure looks allot like the colour. Is this your bathroom or one you have designed??? Simply outstanding!!!

I'm not expert, & no very little about the rating systems. But have heard they're pretty opaque, & as mentioned may not really mirror real world outcomes. I'm surprised that overglazing the northside will result in too much heat loss. If anything, with the right sized eaves, I'd expect it means too much heat gain in winter (& shaded in summer) in the day. But as mentioned by Paul, it's important that you have thermal mass within the home, to absorb this heat. Which can then be released over time as the home is cooling down in the evenings. Thermal mass are heavy materials, like masonry, concrete, & even water. By absorbing heat, & releasing it slowly, thermal mass knocks off the peaks of daytime highs, & nighttime lows, keeping the internal temperature more stable. Without it a lightweight home can become too hot in the day (even in winter on occasions) & too cold at night. Thermal mass is especially important inland, where the difference between daytime highs & nighttime lows (called the diurnal temperature) is greater. So if you are away from the coast of definitely investigate whether you have enough thermal mass in your home. A north facing concrete of tiled floor will do it. It will greatly increase the comfort & energy efficiency of your home. Instead of aiming for the bare minimum when it comes to energy efficiency, resulting in less comfort, & much higher bills. More about thermal mass can be found on this wonderful government website, http://yourhome.gov.au/passive-design/thermal-mass

Thank you for your questions. North is top of page. We’re in Brisbane Qld. Breezes come right side (bathroom, rumpus, Bed1). The western sun would hit the master room wall (without the deck) There would be a 1 mtr eave but we've considered more insulation to compensate. And yes good point about bathroom. It was newly renovated before we bought. It is definitely the “spanner in the works" as that's the best corner for breeze and sun. But moving would incur the additional cost of a new bathroom. (And also where to put it. Would require change of staircase) So it would have to be worth it. Any suggestions for alternatives? the alternative is double internal garage. But we’d have to extend out under the deck as it doesn’t leave much space so external double garage (as in pic) is prob more reasonable. That leaves us a a lot more room to play with down stairs. But no lock up garage security and storage. And yes council should allow. (6m carport) It’s quite common in this area, however we'd have to look at the details of sizing and suitability. We have 5.912mts from edge of deck to front boundary ( 7.812 from edge of house) I'll upload another set of plans with clear dimensions but FYI bed 1 & 2 are 3.6 x 3.6. And block is 10m frontage and 40.5 long.