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

The most efficient way to heat your radiant in-floor and domestic hot water is with a water-to-water geothermal heat pump. If you would also like air-conditioning too, use a triple function geothermal heat pump; full capacity hot water for radiant in floor and domestic hot water as well as forced air for both heating & cooling. Divide your electrical rate by the COP of the GSHP to determine the cost per kW. ItÂs usually a factor of 3.5~5. Geothermal has the highest initial cost but the money goes directly into the value of your home. Geo also has the lowest operating & lifecycle cost and highest user satisfaction rate. Did I mention GREEN? After opening the link below, click 'Products' then click 'TR-Series', then download the R410a Models pdf. SR Here is a link that might be useful: Nordic Triple Function Series GSHP

Jsbjab118, Congratulations on having started your build - exciting and stressful times! We will be building in the Truro area. House likely to be 1 and 1/2 storey with about 1400 sq feet on the main floor, built on a slab, no basement. The builder who recommended the electric infloor suggested using that in the slab, with either electric baseboard or a minisplit upstairs. Although he said we could do infloor upstairs also, in a layer of mud. In our current house we use geothermal and haven't totally ruled that out. I don't think we have much need for air conditioning, just a few weeks of the year. We will face southeast. Too many decisions! Good luck with your build.

I see a number of issues here that you might want to speak with your heating contractor about and perhaps post back. What source of energy are you using for your hydronic heat? In-floor radiant will likely require a lower liquid temperature than your baseboards. What type of baseboards are you planning to install? Cast iron would be best, as they require the lowest fluid temperature. In-floor radiant spacing varies with supply temperature, as does Btu rating of all types of emitters (radiators). The nice thing about in-floor radiant when combined with high ceilings, as in the case of your first floor, is that anything happening above your head (~ 6-ft) is irrelevant, who cares? This is radiant; you don’t have heat the entire volume of air in the room. This concept coupled with the lowest liquid supply temperature design yields the greatest energy efficiency and monetary savings. Your piping distribution system has to be properly designed from the ground up for maximum efficiency and comfort – particularly for individual control of 2nd floor rads. Hire the right expert – regardless of cost! Regarding programmability on the 2nd floor, I would suggest individual mechanical thermostats for each emitter (radiator). This way each room will be its own separate ‘zone’ with a minimum of installation complication. If you were installing hydronic fan coils instead of radiators, you could then have, in conjunction with a geothermal heat pump, hydronic heating, domestic hot water heating and central hydronic cooling (air-conditioning) without ever having to install ducts or mini-splits! Design & documentation of the piping distribution, as well as boilers & HPs, is critical to comfort, energy efficiency & resale value. Hire the right expert – regardless of cost (Yes, I’m repeating myself)! IMPO SR Caleffi Thermostatic radiator valves