Thanks everyone! This first round of advice has been excellent and I'll have an amended floor plan up soon after I make quite a few changes! I thought I should also post the floorplan that has been my favorite so far, there's just too many rearrangements that I need with the bedrooms to make it modifiable. http://www.architecturaldesigns.com/garage-plan-3849ja.asp annie - At the moment I just used the "auto stair", so I'm not sure why they're coming out too narrow. I'll play around with them though and probably go back to the original idea of just a standard straight stair rather than including the landing. I do like the idea of the stairs coming in by the mud room since the space in the future will be more of an in law/guest suite. I had a hard time deciding on going with a shower or tub, but I think I like the idea of stackable W/D to get the extra tub space (or just playing around more that entire arrangement in general). I can easily give the 3rd car a bit more room. The fireplace would be fake (I put it there just to get an idea of space). I wasn't aware of the small house forum, so I'll definitely check that out! The kitchen is the only thing that I think needs to remain large (although some space can be cut down. Cooking is quite important to my bf so he wants the space (I will be redoing the layout though, that was a very rough section). I'll look into some peninsula ideas though to see if they'll suit his requirements. MrsPete - I'd really like to check out your second link, but it won't come up (404 not found). The third option is okay, but I'd like to stick more to the $125 mark which is why I'm trying to get my plan under 1000 sq feet of living space. Greendesigns - I'll be double checking, but the only potential hindrance is that it needs to be connected to the house to be a rental property. The space being a future rental property in the future isn't extremely important to me. It's use as a guest suite and potential in law suite will work fine. My property already has the power and septic for a full sized house on it (there was a previously demolished house). There will still be many developmental costs, but it's still significantly lower than building a 2000+ sq ft house. My goal of this first post is to significantly reduce the size of the current layout. Some parts of the kitchen can be reduced, but since we'll be living here for probably a couple of years, having a decent sized kitchen is quite important to my cooking bf. palimpset - I thought the U shaped staircase would give me some more upstairs space, but from everyone's opinion it wont, so I'll make sure to fix that. red_lover - So far I haven't found an architectural plan that's even close to what I'm looking at. I'm still searching, but there's nothing that's close/modifiable that I've found yet. I'll be moving out soon, so it's either build the garage apartment or buy a house and delay building at all for several more years. renovator - I'll be changing back to a straight staircase, I didn't realize the headroom issues (the camera software makes it look like there wouldn't have been a problem), but the U shaped staircase wasn't something I had fallen in love with. The scales are the same, the first image is just zoomed in. We'll definitely be doing heavy insulation. virgil - The link didn't work (it goes to the site, but not the plan). I'll continue playing around with the 2 bedroom arrangement(mainly 1 bedroom and an office), but having an outside staircase is not going work. I'll be redoing it anyways to have a standard straight staircase, which should solve some problems.

"I will ask for a load calculation report." If nothing else, do this. And as said, don't accept rules of thumb or "I've been doing this X number of years." With new construction, a load calculation absolutely needs to be done. Unlike changeouts in existing homes, you now KNOW all of the building variables that affect the load. I can tell you right now that I suspect gross oversizing for new construction, and zoning the 5 ton system is a bad idea and can be problematic, as mentioned. Zoning is great when done right. Multistage equipment is the way to go if you choose zoning, and I recommend it for comfort purposes regardless. The heat strip is for the electric heat. Not a fan of the 25HBC outdoor units due to their lesser level of coil protection and less sound attenuating features, to say the least. They are a base grade unit. I would at least go with the Performance series outdoor units (like 25HCC6 or 25HCB7). If you're looking at Carrier equipment and zoning, Carrier's Infinity is a good system (25HNB6) but should be paired with matching Infinity indoor equipment/controller, which is not what you were quoted as an upgrade. But poorly installed, you'll hear all sorts of horror stories. I don't know what your time frame is, but you're doing the right thing by educating yourself now. Doing HVAC right the first time will pay off enormously in comfort, efficiency, and longevity down the road. I would personally place a large emphasis on proper duct design -- sizing/layout. See what their plans are in terms of duct material, size, insulation value, etc. Flex duct done right is okay. Flex duct, as often seen in new construction, done poorly leads to inadequate air distribution. This post was edited by ryanhughes on Tue, Mar 19, 13 at 17:24

Hi Pjcampo You have answered your own question in your question however there is no right or wrong answer to this. There is advantages and disadvantages to both with cost and practicality. If cost is the weighting factor then choose a local builder and get him to do a feasibility on it, (give you his best estimate to what is cheaper). If practicality and use of space, considering you storage issue, then going up is the obvious answer. Considering resale is a mute point. Your'e not building it to sell your building it for you. Of course you need to consider this but when you sell it the potential buyers will be asking themselves the same questions as you are now. Consider the classic of "we must have a bath in the bathroom for resale" but no one actually uses it Good luck :)

It's a challenge to get all the utilities done "once" - because you don't want to run electrical for a small apartment today and then again for the house. and you don't want to do a septic for 2 bedrooms and then end up with a total of 5 and have to redo the entire system. The problem them in oversizing the systems to avoid doing it twice is that you spend a lot more money up front, usually when cash is tighter, and you can't get money loaned for the start of a project like this. Certainly doable - requires planning, and more self funding than you expect.