New House, Brain is melting

Eric_U

I tend to get wordy so I apologize in advance. I'll start with come back story, questions will be at the end if you want to skip

My wife and I are from South Carolina and just moved to Central NY so she can attend Cornell's veterinary program. We have both lived in old crappy houses our entire lives, with the last ~12 years being together in a 1994 mobile home (zero air tightness). Luckily, it rarely dips below freezing and we haven't seen snow in about a decade. While our budget is such that we are not going to be building our dream home, we've come up with what I think is a pretty decent compromise: We are building a 40x104 barndominum. The structure will be sheathed, with four inches closed cell spray foam on the roof deck, three inches on the walls, and R14 foam board under the slab (it is a non-weight bearing slab on grade house). There will also be 3" of foam board around the perimeter. The windows are Andersen 100 casements with low-e + heatlock glass. I had never run a Man J before but I downloaded the trial version of LoopCAD and came up with 45k btu heat loss. As a second opinion, I emailed Arctic Heat Pumps my info and they came back 42k btu heatloss, so safe to say I'll be somewhere in the neighborhood.

Though this is not our dream house, I am wanting to put in a few nice-to-haves, such as radiant heat. For months I've been researching air-to-water heat pumps from brands including Mitsubishi, Daikin, Nordic, Arctic Heat Pumps, Enertech, Taco, SpacePak and more. Most of the units are difficult or impossible to get in this country, and digging into the specs most top out at around 35k btu. SpacePak is one of the exceptions with units that go above 60k btu, though at -4F it drops to right around 42k. Where I'm at the average lo temp by month is Jan with an average low of 16F so I think the SpacePak would be ok.

However, this past week I've been putting together all of the components and holy cow are there a lot of additional options. To back up a smidge, I found a PE of fourty years that was going to design my system when I met him last year, but then when I came to him with radiant and air-to-water heat pumps he got confused because...HE HAD NEVER EVEN HEARD OF THAT TECHNOLOGY! He then tried to sell me on putting mini splits in every single room (6-8 would be needed) so I quickly dropped him. Back to present, I have found another person/company (heatloadusa.com) that I am about to pay to run a full Man J/S/D. However, I still need to tell her (them?) what some of the equipment will be, normal duct vs high velocity, etc

This is where I need help. I was mostly settled on getting the SpacePak ILAHP, but I'm not sure if it would be better to get their SIS unit so I don't need a 45% glycol mix (but the SIS is $3000 more expensive), not sure if I can hook up a regular air handler to that to avoid how expensive high velocity runs are (I'm assuming I could?). Would I need a backup electric boiler as a backup? considering the price of a boiler vs ILAJHP/SIS, would it be better to just skip a heat pump altogether and just run an electric boiler. If I do go with SpacePak, they can also cool which means I'll have duct work, so would it be beneficial to through in their $1000 electric heater to the air handler?

Another thing, HeatLoadUSA doesn't do makeup air calcs, but I'm assuming I would just match the Fantech CFMs to that of my range hood? (750cfm in both cases).

Main goal is to be all electric and energy efficient as possible within reason (eg can't afford geothermal). Today I was also reading a post on Green Building Advisor about how it can take awhile for in-slab radiant to catch up if the outdoor temp had a big fast swing when the sun goes down.

I thought I was so prepared now my shell is going up in a few weeks and I have no clue how I'm going to heat it this winter. Any advice is greatly appreciated.

PS Attached are my blueprints. We are not pouring a slab or conditioning the barn portion whatsoever (other than tack room, just pretend that is an office or spare bed room) and the garage will only be heated to maybe 55F in the winter (the two giant garage doors will be R18 btw).

Larry Weingarten

Hi, Is it too late to increase the insulation in the walls and roof? Those measures would make heating the place easier and cheaper. Just to expose my slant, my walls are 8" foam and the roof is 12". Heating is very simple.

Yours, Larry

Hot_water_fan

Radiant heating a home with AC is definitely a splurge, as you’re finding. Few Americans go this route because of the expense. If you can live without the in-floor heating, a centrally ducted heat pump meets all of your needs. 

If not, this is your guide: https://www.caleffi.com/sites/default/files/media/external-file/Idronics_27_NA_Air-to-water%20heat%20pump%20systems.pdf

It is extremely simple to include an electric boiler with an Air to water heat pump. 

Jamie Hall

I rather agree with @Hot_water_fan (probably to his surprise), but with one additional point. Yes, it is extremely simple to include an electric boiler. In the Ithaca area, you are going to want it, so do it. All the literature and enthusiasm will tell you that the heat pump will be quite adequate 90 percent of the time (though they neglect the drop in COP at the low end. They neglect to note that that remaining 10 percent is when you really need the heat... It doesn't get quite as cold in Ithaca as it does in my corner of Connecticut, but for a reality check, the low last winter with -15, and it stayed below 0 for two weeks...

EdTheHeaterMan

My wife and I are from South Carolina and just moved to Central NY

That was your first mistake.

Not the move... the getting married part

We are building a 40x104 barndominum.

Is that so she can house the animals for homework?

I found a PE of fourty years that was going to design my system when I met him last year

That is your second mistake.

I thought I was so prepared now my shell is going up in a few weeks and I have no clue how I'm going to heat it this winter. Any advice is greatly appreciated.

Well you came to the right place.

Air To Water heat pump

Probably the best idea in your situation. It will offer you lower operating cost over the electric boiler idea. There is at least one design that dumps all the heat from the heat pump into a buffer tank. From that buffer tank you can use the water from the tank to heat your floor tubing, or a fan coil in any type of ductwork system, be it high velocity or standard. That tank will have cold water in the summer months for cooling with a cold water coil in the ductwork. Although some efficiency may be lost in the transfer from heat pump to water to air handler verses the direct refrigerant coil in the air handler, the technology has been in use for over 100 years. I believe that properly the efficiency difference is more than offset in the efficiency of inverter technology. (Both water lines will need to be insulates with a contiguous vapor barrier because those cold water pipes will sweat condensation if not protected.)

If you need some help in designing the interface with the radiant floor system to the buffer tank, I would be glad to lend my experience in designing control systems to that end.

1. Select a simple standard duct design with legacy wiring R,Y,G,C with perhaps an ECM or standard PSC motor for the blower fan motor. That ductwork is less expensive.
2. Install the radiant floor tubing because it is easier before you pour concrete, and nearly impossible after the concrete is set.
3. once you have selected the equipment then we will figure out how to connect them if there is not a ready built diagram for the equipment you select.
4. Leave room for an electric boiler to be added if needed. just a few tees and valves are all that is needed.
5. And most important: Pick a good water to air heat pump. The SpacePac you were looking at appears to be spot on!

Are you going to heat the barn with this system? That should probably be a completely separate system independent of the home system.

tim smith

I have been a little in question on the air to water heat pumps out there so far. I know that Europe and Asia have some of the more main line mfrs equipment which is what I have waited for. Would love to see Mitsubishi bring theirs to USA but they keep teasing and not here yet. Be that said, it seems like Spacepak hydronics have been out a while and I guess Arctic has too. Have you already put the tubing in for the living quarters and garage slab? I think the master bedroom would be best served by a mini split heat pump. The main floor if tubing in maybe the sis unit but I wish I heard more solid reviews on them. Not that I heard negative but just more reviews to try and decipher their performance and reliability. John Siegenthaler PE was doing some beta testing for them at his place in you neck of the woods. He might be able to shed some light. Note: he was hired by them for trial testing to evaluate. He is always helpful. Not sure how much help above is, just my observations.
Tim

Eric_U

@EdTheHeaterMan Ha! Yeah marriage is interesting. Barn isn't for homework, she's just an equestrian (mistake three, never marry an equestrian or you'll forever be broke).

We aren't planning on conditioning the barn because of all of the dust and stuff would probably clog any filters in a week. Besides, some insulation and horse body heat will keep things plenty fine.

@tim smith I think Arctic has only been out for around 7-8 years and I'm avoiding them because I talked to who I think was the owner on the phone and he was a borderline jerk, and they only offer a one year warranty; that's not a lot of confidence in a system that costs $15,000-20,000. SpacePak has been around a little longer, has a better warranty, and actually use Toshiba, Panasonic, or Mitsubishi Inverters depending on the model (the guy at Arctic wouldn't tell me where his units are made or what parts are in them). Not that I'm sold on SpacePak, they just have some literature and are easier to find (can buy on skipthewarehouse.com) whereas you can't get something like a Daikin Altherma in the states at all according to the Daiken rep I talked to.

I should mention, I'm planning on DIYing this (!) because our house plans are still over budget despite all the effort in being as cheap as possible. SpacePak and other brands are monobloc so I don't think it will be too bad as long as I have a good Man D

I did read this article by John Siegenthaler yesterday, and found this schematic on GBA that I might borrow some inspiration from.

I think I do like the idea of the fan coils

hot_rod

I think we have 3 issues of Idronics that deal with air source heat pumps. Good number crunching without the sales spin in them

They tend to follow the different jobs Siggy has done

Around that upstate NY area he has four systems running

The system on Ask This Old House was one he designed also.

https://www.caleffi.com/sites/default/files/media/external-file/Idronics_30_NA_Hydronics%20for%20low-energy%20%26%20net-zero%20buildings.pdf

Hot_water_fan

If budget is a concern, I’d just skip the radiant entirely. Install ductwork and plug a central heat pump in that. You’ll get a well known, established manufacturer and it’ll be cheaper to install, even if you use a pro. 

EdTheHeaterMan

Hot_water_fan said:

If budget is a concern, I’d just skip the radiant entirely. Install ductwork and plug a central heat pump in that. You’ll get a well known, established manufacturer and it’ll be cheaper to install, even if you use a pro. 

But you only get one chance to put PEX tubing in a concrete slab. Just sayin'. I put it in my addition in Brigantine NJ and was not sure that I would ever put a boiler in. Just so happens that I had a slow spell 4 years later and didn't want to lay anyone off. I put the rest of the tubing in the original part of the house with that extra time on my hands. Following summer I bought a modcon boiler and VIOLA! I have warm floors. Could not have done that without having PEX in the concrete floor already.

Hot_water_fan

But you only get one chance to put PEX tubing in a concrete slab. Just sayin'. I put it in my addition in Brigantine NJ and was not sure that I would ever put a boiler in. Just so happens that I had a slow spell 4 years later and didn't want to lay anyone off. I put the rest of the tubing in the original part of the house with that extra time on my hands. Following summer I bought a modcon boiler and VIOLA! I have warm floors. Could not have done that without having PEX in the concrete floor already.

True! May as well lay the pex. 

JUGHNE

There is a T shirt with the phrase "How To Make a Small Fortune Raising Horses"........

smaller print "Start with a large fortune".

hot_rod

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