Thank you for the responses! Brian Knight ~ Our home is one level (on a slab) with three bedrooms. It will be an open floor plan, just over 2,000 sq.ft. When I said "relatively" air tight/energy efficient I was referring to our quest to balance efficiency with using healthy materials (not a fan of spray foam for example). We do want to be mindful of proper ventilation/air exchange and have looked into doing something like this (copied from http://homeenergypros.lbl.gov/group/1000homechallenge/forum/topics/panasonic-whisper-green-w-ductless-heat-pump?xg_source=activity): "Some minisplits may have a small ducted system. Dave Robinson, www.GreenEarthEquities.com buys foreclosed homes in central California that he renovates, using two,1 ton Fujitsu mini-splits. He ducts one to the bedrooms and bath with very limited ductwork located in the hall ceiling. The other unit is ductless, and conditions the living room and kitchen of the one-story ranch homes. There are significant cooling loads with lots of 100 degree weather. His approach of combining ducts and ductless results in simple systems and homes with low energy bills. Dave has case studies posted on his website." Reply by Dave Robinson on August 31, 2011 at 10:12am "To be more exact, we use one outside unit (2 ton is the smallest they make in this model - so we use it on everything). One inside unit is the conventional mini split high on the side wall in the main room ... the one that everyone associates with mini splits. The other inside unit is mounted on the ceiling at the mouth of the hallway & delivers air to all the rest of the rooms thru a small duct system that we mount on the existing ceiling of the hallway. So the unit and all the ducts are inside the envelope. Then new drywall is added, reducing the hallway height about 10 inches. We throw the factory filter away and allow a 20 x 30 filter grille right under the air handler to provide a lot more filter area as well as access to the unit without breaking the building envelope. You can see pics of this hybrid duct design at A Good Business? How Long? Plus Ducted MiniSplit Update (Click the right arrow on the photo in the center of the page and it will take you thru a few other slides from that webinar and you'll get to the Mini Split photos). You'll notice we use galvanized pipe. That, along with the oversized return keeps the static way down which is essential for efficiency on these units. This unit has now been in two years. The owner loves it. Zero problems. Has utility bills less than half of his neighbors. This job also used a Panasonic ERV. We mount the ERV very close to the return of the ducted system and in the pick-up area of the wall mounted unit so all fresh air is circulated by the main system with no additional equipment needed. It works well for us and we have adopted this as our main system. It's the one we specify every time unless we are keeping old equipment that's not too old or too over sized for after our renovation. You'll also notice that we mount the outside unit on the roof instead of on the ground. Lots of reasons." We are thinking this might work with our floor plan: Kirkhall ~ Thanks for sharing your personal experience. I have read more on the HVAC forum. My interest in posting here was to see if ductless mini-splits were at all a preferred choice by those building new homes versus just being used for retrofitting/new additions. Niteshadepromises ~ "Based on all my research the operating costs are pretty substantially lower which we're looking forward to and hopefully might offset the initially higher install cost." This is in line with what we are thinking too! Good luck with your build! David Cary ~ The tax credits are wonderful, however, there is that pesky problem of having to pay upfront. With some budget reworking, this may be possible. However, my concern relates to your comment, "But I'm not sure getting all fancy is worth it.... R20 net walls, good southern exposure with some thermal mass. You won't need that much heat and you shouldn't need a/c." We don't want to pay for more than we need. The difficulty for us has been determining what our need is when factoring in the passive solar. I also agree with: "I've thought about this a lot and I don't know how cold you get but if you have total control of design and southern exposure, your best bet is lots of solar planning, tight house with thick walls. Cover the windows well at night. Then put the money in PV. Code will require too much of minisplits to be cost effective." To satisfy code, what would your recommendation be for a thermostatically controlled system that is reasonably efficient and cost effective (presuming we could swing the PV)? With good solar planning, another viewpoint is to put in some baseboard heaters to satisfy code. Is this reasonable or silly? Dekeoboe ~ I'm interested to know what you chose and why? Flgargoyle ~ As our heating and cooling days are very similar, it's good to know that you think it's a viable option. Though it seems I'm in the minority, I don't really mind the look of the wall units. Maybe it's because I don't find vents and returns all that pretty! Lori in the NW ~ Thanks for your opinion ~ they certainly are not for everyone! This post was edited by daisyblue on Fri, Feb 22, 13 at 17:45

"Loft" means one big open space? Square feet means little compared to insulation, air permeability and climate. Cooling only or heat pump? Manufacturers generally all make a lot of sizes for different applications so I don't understand your problem in choosing your "system". Do you want to heat your water with this system?

I think the bias is largely cost, not so bad if you are installing ducts in fur downs in a home that never had ducts. There is an architect locally that puts furdowns in all his new construction homes. he is known for building energy efficient homes. if it wasn't one of his selling points (the savings we get with ducts out of hot humid attics) the average joe on the street wouldn't realize anything out of the ordinary. his furdowns are simply part of the design of the interior. they compliment the style of the house, rather than being obvious. sadly, he is one of the few on the same page as myself. it is mostly in existing homes that I'm involved in moving both equipment into conditioned space. in most cases we make an unvented foam sealed .. semi conditioned attic..in other cases we seal the ceiling to create a tight air barrier to the attic..and insulate attic well (conventional vented attic with ins on attic floor) then closet fur downs ... as you know, the layout of the house has to lend itself to the furdowns. you can do it simply...like in my house where the only furdown not in a closet is across the kitchen wall ...and just paint it to match the wall. no one really notices mine at all. or you can make the fur down a stand out or part of a trey ceiling. in my experience, it has to be the right homeowner, the right house & hvac company that will either do the furdowns..or just set up for someone else to build furdowns. everyone has to be on the same page. it isn't the most popular install...but is by far the most efficient one. here in hot humid La. there is a savings for getting ducts & equipment out of extreme attic temps. as are in many areas.

We have had an LG Inverter minisplit in our master bedroom suite for about 2 years now. Installed it so we do not have to cool the whole house to sleep comfortable. Anyway, has worked great, is very quiet and very efficient. Its a good heatpump too but we rarely use it as the house is maintained at 68 during the day and we set the night temp to 60 in the MBR but it almost never gets that cool before morning. Would have to be well below freezing which is rare here in Houston.