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

Thanks for the location. Certainly some variation in local climate it seems. What elevation are you at? All things are relative and "cold, mountainous" would be 2 of those terms. Looks like average winter low is about 15 degrees. "Pretty good insulation" would also be relative. How old is the house gives some estimate. Having electric baseboard that far North would probably mean at least 50 years old. I mean I have lived in some very old houses (that would be 100 years old now) in Buffalo and Ithaca and had electric baseboard one time. Sizing is determined by both cooling and heating. Generally - a northern area where heating dominates, the sizing is by heating. Where I live, it is still usually heating despite what people think. But large western windows can change that. Bias alert. I think HVAC folks are going to encourage multiple units and I doubt you "need" them. You could spend $4000 on a single unit and get payback in 2 years. Your could spend $8000 on 2 units and get payback on the second unit - never. But the HVAC guy gets payback right away. Are you living there year round? And, adding to what Charles said - are you open to adding ductwork or not? Are you open to other fuels? I think a minisplit will probably be the best but there are other choices. Probably more like $20k rather than $4k.

I'm with Stax on this one. It seems like the OP has an issue to deal with but sometimes people lash out at comments people make they don't want to hear. Whether a result of limited information or not doesn't matter. Experience has taught me that you can't turnkey home trade services, especially not expensive major projects. I learned the hard way to only schedule such items when someone could be home. And "being home" for us meant checking in periodically, maybe even hourly, with the conduct of the work, no matter what or where. As just one example, for our last exterior repainting job a few years ago, the painting contractor came to me to say they could "catch up" with their "schedule" by working during the coming weekend. I told him we wouldn't be home and I preferred they not do so. He insisted. I said fine but I would go over their work afterwards very carefully. Not surprisingly, I came home on Monday to find they'd done a poor job, the paint applied had been thinned out too much and it was sloppily done. I insisted that the entire side of the house be redone, at his expense for time and paint. They fell behind rather than moved ahead on the "schedule", it was a fixed bid and it was his problem.

Charles, I found this study https://www.aceee.org/files/proceedings/2004/data/papers/SS04_Panel1_Paper08.pdf which as you implied roughly indicates that a system rated with a HSPF of 11 in Zone 4, at best might achieve aproximately a performance of HSPF = 9 in Zone 5. So adjusting my original calculations, it might be reasonable to expect I will use between 5,500-6,000 kWh per year to produce 50,000,000 btus of heating. Additional kWh will be needed for cooling, but several sources imply that I should only expect to use 1,500 kWh or less for cooling the home. So I think if I make decisions based on needing 7,500 kWh annually to run the system, I will be in the ballpark. One of the nice things about this conversation going back and forth is it made me discover that the cost of natural gas with my utility Eversource has increased from $1.89 to $2.20 per therm, which means I would have nearly $1,100 in future annual natural gas expenditures that altenatively could purchase 4889 kWh of electricity. Adding that to the 3,000 surplus kWh produced by the solar, means I have 7889 kWh available to run the heat pumps/minisplits system. I do understand that this means I am not actually saving any money and in fact get no return on the investment in purchasing and installing the system. The questions comes down to will the system prove to be a better longterm investment compared to replacing our natural gas boiler within the next 3-5 years (expected due to age)? Will the cost of natural gas increase more rapidly than electricity? Will it provide more constant and comfortable cooling and heating (not to mention not having to put in and take out the 4 window ACs as well as the kids bedrooms getting cooling - we don't have window ACs there). Lastly, will the system add value to the resale of the house when we seek to move in 15 years. Your thoughts?