Replies

1. GBA Editor
   Martin Holladay | May 05, 2015 04:26pm | #1

   Ben,
   Type "ductless minisplit" into the GBA search box, and you'll have enough reading for several hours.

   When you write about ISO insulation, I assume you are talking about polyisocyanurate. If so, there is no such thing as 2-inch-thick polyiso with a rating of R-20. A more realistic rating (if we are talking about polyiso installed on the exterior side of a wall) for 2 inches would be R-12 during the summer, and R-8 to R-10 during the winter.

2. GBA Editor
   Martin Holladay | May 05, 2015 04:33pm | #2

   Ben,
   Here are some links to GBA articles to get you started on your ductless minisplit research:

   Just Two Minisplits Heat and Cool the Whole House

   Rules of Thumb for Ductless Minisplits

   Practical Design Advice for Zero-Net-Energy Homes

   Minisplit Heat Pumps and Zero-Net-Energy Homes

3. GBA Editor
   Martin Holladay | May 05, 2015 04:35pm | #3

   Ben,
   Here is a link to an article about the R-value of polyisocyanurate: In Cold Climates, R-5 Foam Beats R-6.

4. 
   chiefsilverback | May 05, 2015 04:41pm | #4

   Thanks Martin, you are right, I was getting my values confused!

   I have been reading many of the articles on GBA about the ductless mini-splits and I am starting to come round to the idea. For the last 6 years we've lived in 2 different new construction properties with poorly designed, cheaply installed contractor grade forced air systems and my wife and really want to get back to that warm feeling that a radiant system provides.

   Do you have any info on the relative costs of a Fuji or Mitsubishi mini split vs the Daikin Altherma?

5. GBA Editor
   Martin Holladay | May 05, 2015 04:51pm | #5

   Ben,
   In New England, the installed cost of a ductless minisplit is about $4,000.

   Daikin Alterma units are rare in New England -- hard to get a quote, and hard to service if something goes wrong.

   Some posted comments by GBA readers:

   https://www.greenbuildingadvisor.com/community/forum/mechanicals/14216/seeking-air-water-heat-pump
   Mike O'Brien: "First Daikin Altherma system installed in Portland looks good, however, I got a quote of $22,000 to install a system in our house, and because it is not yet elegible for the 30% Federal renewables tax credit, it's an expensive way to reduce electric energy use. I have to say I don't understand where the high price comes from, the components are pretty straightforward to install."

   https://www.greenbuildingadvisor.com/blogs/dept/design-matters/ground-source-heat-pumps-part-2-rules-thumb
   Nick Lehto: "I got a quote on an Altherma for $36K installed in an 1800 sq. ft. house. It was $4k more than a GSHP after you take CT state rebates into account. IMO they are both too expensive. If you have a superinsulated house its tough to argue against the mini splits at $1500 a pop."

6. 
   chiefsilverback | May 05, 2015 05:02pm | #6

   Thanks Martin and I'm starting to come to that conclusion myself! I'm waiting for a couple of quotes for mini splits so it'll be interesting to see what the different installers recommend and price out.

   I just read through the ISO article and it certainly makes for brain ache as you start to bring all the factors into play. At the end of the day each install is different and the builder/home owner will need to decide on where to draw the lines. Do you chase the most efficient mini-split/HPWH or do go for a something cheaper (GE Geospring vs Steibel Elton) and put the difference into extra PV panels to produce the electricity to close the gap.

   The same goes for insulation, if the purpose of the insulation is to keep the heat/cold you're creating to make your house comfortable from escaping to the warmer/cooler outside air, and the energy to do that is 'free' (PV/wind/micro hydro etc...), are you better investing in the generation or the retention?

7. 
   charlie_sullivan | May 06, 2015 08:33am | #7

   The mini-split option is the most sensible. You could also consider a water-water ground-source heat pump. It would be much more expensive and only slightly more efficient, but that would be a way to avoid the air movement and associated noise of the minisplits, if that feature is worth the perhaps $15k to $20k increase in cost.

8. Expert Member
   Dana Dorsett | May 06, 2015 11:24am | #8

   Polyiso should never be installed over or under a basement slab, since it can wick & retain water. Polystyrene (EPS/XPS) does not have this problem.

   Polyiso between studs (even 2x2s) is a waste of good foam, since a large fraction of it's potential R6/inch performance is given up by the severe thermal bridging of R1,2/inch wood. The "whole assembly" value of the 1" iso + 1.5" of thermally bridged iso layer at a 15% framing fraction is about R11.5, which is below code-minimum performance. But 2.5" of continuous polyiso held to the wall with 1x furring through-screwed to the foundation is about R15, which does meet the code-minimums for US climate zone 5 (barely.)

   Adding 2" of polyiso on the exterior of a 2x4 framed house with R13 cavity fill would beat the R13 + 5c.i. code min performance by about 30%. Before adding the exterior foam it's good to verify and rectify any cavity insulation & air sealing issues, which can be done from the exterior with blown fiber insulation, using blower door & IR imaging to find the leaks & thin spots.

   In southern New England there are multiple vendors of used-once reclaimed foam board and factory seconds (blemished/damaged sheets) at 15-50% of the cost of virgin stock, which can lighten the foam budget by several thousands of dollars. (The big ones are Nationwide Foam in Framingham MA, and Green Insulation Group in Worcester MA, but there are others.)

   There is simply no WAY an insulated 1100' basement in RI has a heat load anywhere NEAR the output capacity of a 1-ton mini-split head or even a 3/4 ton unless you leave the windows open. If going multi-split, a half-ton head would be more appropriate.

   There's also no way the design heat load for the whole house at +10F or whatever is going to be anything like 30KBTU/hr on an 1100' house with 1100' of conditioned basement at your proposes insulation levels. You're probably looking at something between 15,000-20,000 BTU/hr after upgrades, assuming you have at least clear-glass double-panes (or clear storms over single-panes) for windows. (In MA less than 50 miles north of you I live in a less-well-insulated antique more than 2x that size, with a heat load at +5F in the mid-30s.) A tight code-min 1100' rancher with an insulated basement and an insulated slab would typically come in around 12BTU/hr-ft^2 for the first floor, and less than 3BTU/hr-ft^2, or about 16-17,000 BTU/hr. With bigger or sub-code windows you might hit the 20s, but you'd only hit 30,000 BTU/hr with a couple of windows open.

   Almost all 3-zone multi-splits are going to be oversized for your whole-house heat load. If you can stand ducted heating, a single 1.5 ton Fujistu 18RLFCD mini-duct cassette (nominally 20,000 BTU/hr output, minimum operating temp -5F) would more than likely handle the real loads of the "after upgrades" picture. When you have more information to share we can probably narrow down the heat load a bit with some napkin math.

   The Altherma and radiant floors or low temp panel radiators are great and all, but just the Altherma (not the radiation) be 2x the cost of a mini-split solution. The water temp requirements to keep the Altherma in a high efficiency mode would require an above-the-subfloor solution such as WarmBoard or Roth panels, which is pretty expensive.

   At the "as-is" insulation levels you're a long way from PV solar being more cost effective than more insulation. Even with 2" of exterior polyiso you're probably not there yet. At the cost of reclaimed foam you can go quite a bit fatter on the rigid foam and still be ahead of rooftop PV. But it gets a bit awkward to install once you're much over 4".

9. Expert Member
   Dana Dorsett | May 06, 2015 12:08pm | #9

   As another sanity check on the heat load WAG:

   I recently helped a guy in Falmouth Maine contemplating a boiler swap figure out the heat load on his 2x4 framed cellulose insulated 1400' circa 1940 cape, with a full basement (with no foundation insulation) using fuel use against heating degree-day methods. That worked out to about 30,000 BTU/hr @ +2F.

   It was later verified with a Manual-J load calculation by a qualified energy auditor (a necessary hoop to jump through to get weatherization subsidy in his location) which came in at 29,000 BTU/hr (within the calibration error of the measuring instrument: his old boiler.) The auditors who did the Manual-J estimated that with their recommended air sealing and insulating the foundation walls (but not the slab) the load would drop to about 20,000 BTU/hr.

   That's a 25%+ bigger house than yours, with a ~10% colder outside design temp, and only half the wall performance you would have after adding 2" of exterior foam. And since you're insulating the foundation walls AND the slab your basement losses are likely lower than his (unless yours is a walk-out basement with a big glass slider or something.) If your basement is mostly below grade and not a walk-out, even the "before upgrades" heat load is likely to be under 25,000 BTU/hr.

   A mini-duct type mini-split with the cassette & ducts in the insulated basement will be cheaper and more appropriately sized than a multi-split. The better class 1.5 ton mini-duct efficiency now meets or beats the performance of cold-climate mini-splits of even 4 years ago. And the 0F out capacity is comparable to or bigger than more expensive modulating heat pumps such as the 2-ton Carrier Greenspeed (which is a great heat pump, but overkill for this house.)

   The smallest 3-zone multi-splits have 2 ton compressors with about 30,000 BTU/hr of heating capacity, which would be 2x oversized for your loads. The minimum load for the compressor would be a large fraction of your average winter load, which means it would be cycling on/off more than modulating. Even with three 6000 BTU (cooling rating) heads, you would have over 23,000 BTU/hr of heating capacity @ +10F. All of that adds up to a more expensive, less comfortable, and less efficient solution than a single1.5 ton mini-duct type that's only ~30% oversized for the load.

10. 
    chiefsilverback | May 06, 2015 12:54pm | #10

    Thanks for the informative posts a Dana, I really appreciate you taking the time to weigh in. I'll try to upload my proposed floor plan for the renovation, but I'm on my iPad at the moment so I'm not sure it will work.

    Just to clarify though, we would be looking to create a ~1900 sq ft property comprising 800sq ft first floor (currently basement) and 1100 sq ft 2nd floor. The basement is 36'x24' and the house was expanded over a 24' x 12' crawl space at some point.

    All 4 basement walls have some portion above grade, with the west and north walls beings the most exposed, and yes we do plan to have an 8' slider in the west facing wall.

    
11. Expert Member
    Dana Dorsett | May 06, 2015 02:18pm | #11

    The compact mostly rectangular L footprint design is good for efficiency due to the lower exterior surface to floor area ratio. It will be important to insulate & air seal the crawlspace walls, even if you don't insulate the crawlspace floor to keep the addition from having different load profile from the rest of the upper floor.

    If you go with a heat pump water heater (recommended), putting it in the utility room directly under the master bath would be the most appropriate place, since it would have the least noise impact. They're not super-loud, but it can be like a window air-conditioner, quite a bit louder than your refrigerators.

    How much above-grade exposure is there on the foundation? It makes a difference if it's 1.5' vs. 4.5' (which would make it much like "raised ranch" split level)

    Sliders are usually a lot leakier than air tight than swinging patio doors, and have only about half the opening of swinging doors too. You can get get a bigger doorway at a lower amount of glazed area if you make it a paired 5-6' of narrower swinging doors than an 8' slider, and if you pay attention to the weatherstripping details it'll be quite a bit tighter too.

    West facing glass also drives the peak cooling loads higher, much higher than with east facing glass of equal solar gain, since the late-day gains of west facing glass occurs when the air temps are higher, and after the house has been heat-soaked in sunlight all day. If you're still going for west facing glass doors, keep revisiting the cooling load calculations. A west facing 8' slider probably more than quadruples the otherwise low peak cooling load of the basement zone.

    For daylighting purposes north facing glass is more useful than west facing glass, with dramatically less unwanted gain, and shadow-free light. As long as the U-factor of the door is less than 0.35 it will still be a net energy gainer during the heating season. (But even if it's a net heat gain, higher glazing fractions still increases the peak heating load.)

    South facing glass is better for passive gains during the heating season and with the appropriate overhangs or awnings will have fairly modest summertime gains due to the high angle of the mid-day sun.

    Since you're turning the basement into kitchen & living room space you may have to go with separate heating & cooling for the basement & fully above grade portions to achieve reasonable temperature balance, since the below-grade heat loss & gain characteristics are quite different from the fully above grade floor. If the living room was an archway to the kitchen rather than doors it could be served by a 3/4 ton wall coil type mini-split at somewhat higher efficiency than a 3/4 ton mini-duct cassette (either of which would be oversized.)

    There are1.5 ton 2-zone multi-splits that could handle it with just one compressor, but you would be looking at an HSPF efficiency 9-10, compared to 11-12 for best in class dedicated single-zone mini-duct cassette mini-splits, or HSPF13-14 for best-in-class 3/4 ton & 1 ton wall-coil types.

    It will be important to calculate the loads more carefully both room-by-room, and zone by zone as you tweak the design. It's useful to build a I=B=R spreadsheet with the room totals and the zone subtotals. If you need help figuring out the appropriate U-factors at different foam & cavity fill types & thicknesses it's not too tough to come up with reasonable estimates. You can use the published U-factors for the windows & doors, and there are standard U-factors for attic insulation of different depths/types published in multiple places on the web. An I=B=R calculation is really a firm upper bound- usually 15-20% over reality (or a carefully aggressive Manual-J.)

12. 
    chiefsilverback | May 06, 2015 02:43pm | #12

    The door(s) between the living room and kitchen will be open the majority of the time, it's just nice to be able to close them when you're cooking or the kids are watching TV... I was thinking about sizing that wall to accommodate the Fujitsu slim duct unit that would serve both rooms?

    We will have a wood stove in the living room.

13. Expert Member
    Dana Dorsett | May 06, 2015 03:26pm | #13

    When you're looking at tiny loads, the minimum modulated output becomes important.

    The min-modulation heating output of a 3/4 ton -9FFujitsu slim duct is 3100BTU/hr @ +47F. That 3100 BTU/hr could be as much as half the heat load of that zone at +10F.

    The Mitsubishi MSZ-FH09NA wall-coil type mini-split can more than cover the peak load of that zone, and has a min-mod output of 1600 BTU/hr @ +47F.

    http://www.fujitsugeneral.com/PDF_06/Submittals/9RLFCD%20Submittal.pdf

    http://www.younits.com/media/wysiwyg/Literature_PDF/Mitsubishi/MSZFH09NA_MUZFH09NA_Submittal.pdf

    The competing Fujitsu 9k wall blob is somewhat higher efficiency than the Mitsubishi, but has the same 3100BTU/hr min-mod issue as the mini-duct cassette:

    http://www.fujitsugeneral.com/PDF_06/Submittals/9RLS3HSubmittal.pdf

    If you're willing to leave the doors between rooms open during cold nights the -FH09 is probably a better choice for the basement zone than anybodies mini-duct cassette.

    A woodstove in a 225' room in a zone that has a very tiny load can have something like a sauna-effect. That can be mitigated a bit by using a higher-mass soapstone stove, but look for the smallest BTU output you can find. Something under 25,000 BTU/hr @ max-fire or less (maybe 35K, if soapstone.) If you oversize the stove by a ridiculous factor it will never run at it's rated-efficiency or lowest pollution mode, and for 750' of insulated mostly-below-grade space, most wood stoves are ridiculously oversized. Most wood stoves have to hit at least 1/3-1/2 the rated firing rate early in the burn to hit anywhere near the tested particulate emissions numbers. In smolder mode emissions are something like an order of magnitude higher, and the efficiency takes a dive to boot. Before committing to the wood stove it pays to calculate the actual heat load fairly aggressively.

14. 
    chiefsilverback | May 06, 2015 10:56pm | #14

    With regards to the above grade portions of the basement walls, the west and north walls are completely above grade, the East wall 30% above grade (grade slopes down from South to North) and the southern wall has the crawl space along 66% (24') of and the remainder is about 25% above grade.

    We would definitely go with a HPWH located in the basement utility area. With a current $750 credit in RI the GE Geospring seems like a no brainer, but is something like the Steibel Eltron worth the extra money?

15. 
    chiefsilverback | May 08, 2015 08:32am | #15

    I've just received a quote of $20,000 to install 54K BTU of Mitsubishi mini splits! A 24K system in the basement with two heads (9K & 12K) and a 30K ducted unit upstairs!i

16. 
    user-2890856 | May 08, 2015 10:05am | #16

    Geez ! Seems like high heat loads and bad design run rampant through every sector . For a bit more than that you very well may be able to install what you originally inquired about at the other site Chief SB . I'm just judging by NJ prices though , maybe your market is more expensive .
    I just bid a job a bit smaller than yours with a similar design load . Envelope is lacking . If I added the required extra radiation that you would need based on 4 more panel radiators with TRVs that may be needed for your home and accounting that the others would be markedly smaller I would venture a guess that your home would cost 24,000.00 to complete . Don't lose sight of the fact that my system also provides hot water . The radiant that you first stated would be optimal would of course be more . But panel radiators with TRVs allow a comparable comfort level and unsurpassed room to room control without wires .

    @ 30K the system i would design would use 515.67 gallons of LP per year for space heating , cooking , dryer , DHW . This is based on 30,000 BTUh x 24 hours x 6166 HDD ( 2014-15 from Green Airport) x .6125 (CF) divided by AFUE (.90) x 93,000 (fuel content) x 63 (DTD) . Added electric use for pumps and equipment is about 35.00 year .

    Electric would of course be the same except the 93K would change to 3414 (fuel content) and the point 90 AFUE would become an even 3 ( assuming a COP of 3) which would give you a required usage of 21,071 Kw .

    I'll allow others to verify my math or pick it apart . Put as high a COP on it as you want , I'll let the numbers speak for themselves . Then you can size and install the mini splits for just the cooling load at a much lower load and use ductless .

    I appreciate the real bid from the real contractor , who might I add also screwed the pooch on the load and the system design .

17. Expert Member
    Dana Dorsett | May 08, 2015 01:41pm | #17

    54K of capacity for a house with a probable heat load of 15K-20K is simply fug-nuts! Not even the "before" picture has a heat load anywhere near 54K, assuming the windows have glass in them!

    Seriously- run a I=B=R spreadsheet load calc on the "after" picture, AND insist that any equipment quotes be accompanied with a detailed Manual-J, and LOOK at the load calculation details, if it's actually higher than your estimate. (Hiring a qualified engineer or architect to run a Manual-J on the "after" picture would be even better.) Let the contractors know before quoting it what YOU think the heat loads are, and make them prove their numbers if they disagree.

    Even the $4444 / ton pricing is on the high side for 4.5 tons of ductless being installed all at once in the same place. To be competitive in central MA it has to be under $3.5K / ton. I'm aware of one recent project that was 3 x MSZ-FE18NA (=4.5 tons) that came in under $3K/ ton, all installed on the same building, and there were multiple bidders in the $3K / ton range. The ducts add some cost, but not that much cost. Can you share with us the model numbers they were proposing?

    It's those sorts of proposals/quotes that drove me to specifying my own HVAC equipment...

18. 
    chiefsilverback | May 09, 2015 02:09pm | #18

    They didn't provide model numbers for the dual zone in the basement, just a 24K Mitsubishi with a 9K and a 12K head. By my reckoning you could get the M2H20W09150000-A which lists for $2600 online to cover that. They are quote $6,1000 to supply and install that.

    The upstairs system specifies the PEAD-A30AA4 indoors and the PUZA30NHA4 outside, at a cost of $11,900.

    The balance of the $20K is for a 50 gallon Geospring.

    Based on the discussion in this thread it seems like the MSZ-FH09NA would cover the basement load and that can be had for $1600 online.

    I'm definitely leaning towards a single head upstairs as well and then use the ERV to move the air. There's an article here on GBA that talks about placing the exhaust vents in the bedrooms to move the air through the house, with the inlet located in the hallway near the head.

    Re. the comments on installed costs surely the $/ton should not be linear? The Mitsubishi MZ-HE12ANA can be had for ~$1300 and the MZ-HE24NA for ~$2000. The installation costs must be identical so if you could get the 12K installed for $2K the 24K should go in for about $2700, not $4K!?!?

    I will create and I=B=R spreadsheet over the next few days.

19. 
    chiefsilverback | May 11, 2015 01:33pm | #19

    I just got off the phone with the guy who provided the quote I posted about. He's using a benchmark of 1 ton of AC for every 400 sq ft of floor space and allowing a bit of spare capacity for the dead of winter.

    He did offer up a revised figure of $4000 to install a one zone 15K Hyper Heat in the basement, but given I can buy that unit for $2K online, paying the same again for installation feels a bit steep!

20. 
    user-2890856 | May 11, 2015 02:17pm | #20

    Ben , Please don't take this the wrong way . I am quite sure this gentleman has overhead like fuel insurance , labor , truck payment , office expenses , you get the idea . How do you suppose these things get paid . He is also probably charging as one should to remain in business so he is here for his customers later on also . This is not a hobby and I'm sure he probably does not need the practice .

    I once had a guy tell me he could buy all the stuff online for 2/3 of my price on a DIY site . I politely told him he should do that and do it himself . The first rule of business is profit .

21. Expert Member
    Dana Dorsett | May 11, 2015 04:26pm | #21

    I'm not sure that the MZ-HExxNA series makes ANY sense at all in this climate. The 2-ton HE24NA has the same +5F max heating output as the 1.5 ton FE18NA, and a dramatically lower HSPF efficiency (8.5 for the HE, 10.5 for the FE.)

    The cost per ton isn't exactly linear, true, but within a range of tonnage split between multiple heads or independent mini-splits the cost per ton range is pretty bounded. The more equipment being installed, the lower the $/ton SHOULD be, which is why $4.4K/ton seemed a bit steep. An FH09 might cost $3-3.5K as a one-off installation, which puts it in that $4.4K/ton range, but if you were installing 3 of them the price per unit & price per ton would come down.

    Unless the individual room loads are VERY low you'll be better off with a mini-ducted solution for the upper floor. Moving the air around at a very low temperature difference with the ventilation system is not a very satisfactory heating solution unless the room loads for doored off rooms is on the order of 1000 BTU/hr at the 99% outside design temp or lower.

    A rule of thumb of 1 ton of cooling per 400' of conditioned space is completely gonzo, totally out to lunch, even if you moved that house to south Texas (famous for being hotter than hell, which is why the devil didn't set up in Texas. :-) ) The ton per 400' rule of thumb has been around since the 1950s, when windows were all clear and single-pane, attics were all but uninsulated, many walls were not insulated, and houses (and ducts) leaked air like as sieve. Since the ton/400 rule reliably oversizes the cooling equipment even for THOSE houses- how do you think your house stacks up? A ton per 1000' is more typical for new code min houses even in cooling dominated parts of the US, but in RI it's often a ton per 1500' if it doesn't have much west-facing window. The fact that the lower floor is mostly below grade your cooling tonnage/floor area ratio is likely to come in about that, but run the numbers.

    The west facing slider in the master bedroom isn't doing you any good, nor is the west facing slider in the kitchen. You might consider installing exterior roll-down shades (Cool-a-Roo or similar) to limit those late in the day low sun angle gains in summer.

    Installing an FH15 in the lower level is completely nuts unless you install solar concentrating mirrors to boost the gain through that west facing slider. With the walls insulated to R15 c.i. and something like 2/3 of it being below grade and with conditioned space above, the FH09 is would likely cover the loads.

    Bottom line, a rules of thumb approach doesn't work all that great even on a code min house, and on a high-R house even less so.

    The internet pricing usually doesn't include the mounting equipment nor the refrigerant lines, and DEFINITELY not the burdened cost of labor,(paid anybody's health insurance premiums these days?) the tools, the training, the office overhead, etc. Assume that you can usually get a professional installation for something like 2x the cost of just the mini-split, and that will cover any damage caused when they accidentally drill through your powerlines or something, and will come with both a parts & labor warranty for some amount of time. While it's not rocket science to install one, even as a DIY it usually cheaper to do 95% of the installation yourself then have a certified tech come do the pump-down, refrigerant charging and commissioning tests that it is to buy the tools to do the whole thing yourself, let alone train yourself on the finer points. In locations where the nearest certified installer is 50-100 miles away a DIY installation of a unit sourced via web-store sometimes make sense, but probably not in your case. The contractor proposing the 4.5 tons of gear isn't right for the job (at least from an equipment specification/sizing point of view), but there are others.

22. 
    chiefsilverback | May 11, 2015 08:07pm | #22

    Hi Richard,

    I do appreciate the costs of running a business and I'm not suggesting a professional should charge 10% more than an online reseller. I use those numbers more as a starting point. If the hardware costs $2000 and the installed costs is $4000 there's a natural curiosity as to what that $2000 covers, especially for a single zone mini split being installed in a relatively compact 'bare walls' remodel.

    Dana already covered some of the cost differential, mounting brackets, line sets etc... I just wonder where the rest goes? I also don't say this purely as a cost conscious consumer, but also as someone very interested by home building and everything that goes with it, so I really like learning about all of this stuff.

    I think if I can get the installed cost to $4K/ton or lower and I only need ~2 tons that's not too bad.

23. 
    iLikeDirt | May 11, 2015 10:08pm | #23

    The money goes towards:
    - Hired labor
    - Taxes
    - Advertising
    - Cost of free estimates
    - Health insurance
    - Vehicle payment
    - Vehicle fuel
    - Vehicle maintenance
    - Vehicle insurance
    - Vehicle replacement fund
    - Professional insurance
    - Professional organization membership fees
    - License fees
    - Website costs
    - Profit
    - Etc.

    Why are these things so high? Mostly, because contractors have incredibly economically inefficient businesses. Since their businesses are small, fixed expenses are a high percentage of the total. Since all the work is unique, site-specific, and non-repeatable, customer acquisition costs, site-specific expenses, and vehicle-related costs are high. Since the fields are highly regulated by government, things like taxes, fees, and insurance costs are high. And who pays all of those costs? You do.

24. 
    chiefsilverback | May 11, 2015 10:58pm | #24

    Thanks Nate, that's very useful and provides real food for thought.

25. GBA Editor
    Martin Holladay | May 12, 2015 05:21am | #25

    Another one: warranty service and correction of mistakes.

    When homeowners decide to play contractor, this is the one that comes back to bite them.

26. 
    Dana1 | May 12, 2015 07:34am | #26

    "I think if I can get the installed cost to $4K/ton or lower and I only need ~2 tons that's not too bad. "

    You'll probably need 2.25-2.5 tons to have reasonable oversizing factors for the heat load. Without actually running the heat load numbers against the output capacity, you're probably looking at a 1.5 ton cold-climate mini-duct mini-split for the upper floor, and a 3/4 ton (ducted or wall-coil) unit for the lower level. For all-ductless it would probably come in around $3-3.5K/ton, with a mini-duct unit the duct system adds to the installation costs, so $4K/ton or even a bit higher wouldn't be out of the question.

    In this climate the Mitsubishi's mini-duct units fade pretty fast on capacity at your 99% outdoor design temps. The Fujitsu's mini-duct units are probably the better choice for ducted system. But for ductless there are excellent options from Daikin, Mitsubishi & Fujitsu.

27. 
    chiefsilverback | May 12, 2015 09:37pm | #27

    I've used the SlantFin calculator to run the room by room numbers on the design using the following assumptions:

    Basement walls - R21
    Basement floor - R11
    Frame walls - R41
    Attic - R54
    Windows/doors - U factor of 0.36

    The heat losses at the following design temps are:

    0 ext/70 int - 28,000
    5 ext/70 int - 26,200
    5 ext/68* int - 25,400
    10 ext/68* int - 23,400 (13.2K basement, 10.2K 2nd floor)

    The split between basement and 2nd floor is roughly 56%:44%

    *During the heating season we don't set our thermostat above 68 hence the loads at that interior design temperature.

28. 
    chiefsilverback | Sep 30, 2015 06:37pm | #28

    I realise I rather left this thread hanging. We actually decided to pull out of this purchase and we're renting whilst we decide our next step.

    Thanks for all your responses!