" it's the ducted HVAC marketing guys that are making tens of thousands of dollars per home install."
Really? I can't hang with a lot of Ricky's comments, but this might be more outrageous. Fight BS with BS?

It is absolutly true that ductless is more efficient than ducted regardless of technology. That doesn't mean one size fits all. Not every home would benefit from either technology.

Green Building Advisor Articles on Ductless Mini-Splits:

GBA1

GBA2

GBA3

GBA4


Please read these scientific articles written by professionals and please stop with the aspersions you are making against forum members. We can have a discussion and even disagree but you really need to tone it down if you are going to be taken seriously here on this forum.

Posted By Lbear on 12 Mar 2014 12:29 AM
Green Building Advisor Articles on Ductless Mini-Splits:

GBA1

GBA2

GBA3

GBA4


Please read these scientific articles written by professionals and please stop with the aspersions you are making against forum members. We can have a discussion and even disagree but you really need to tone it down if you are going to be taken seriously here on this forum.

Listen here .... Someone attacks me for posting a legit concern, than Shame on them and the one defending him.

I read the propaganda articles some time back...



ENERGY STAR Most Efficient 2014 - Air Source Heat Pumps
http://www.energystar.gov/index.cfm...e_cac_ashp

If you notice most all of the Mini Splits heat pumps are 3/4 to 1 Ton units which is rather irrelevant unless you have a 800 SF Mud Hut in the jungle ..... How well do you think Carrier units would perform if they designed and built 3/4 ton VFR heat pump units and marketed them like Mitsubishi and all the others do ...... ..... Did I just see you shrink down in height

Also if you notice energy star did not publish Mini Split VFR systems in the 2, 3 4 or 5 Ton range ..... Hummm wonder why ..... Lets do a quick investigation

Fujitsu  4 zone system - 3 Ton unit one of the most efficient units out there on the market can only do 16 SEER .......
https://www.goductless.com/Fujitsu/...t=&subCat=


If you like I can keep tearing holes in your britches, before you know it you will be the Emperor with no cloths.

Posted By ricky_005 on 12 Mar 2014 01:26 AM

Apparently you are not mature enough to discuss something civilly without resorting to personal attacks and condescending posts.

Well, we tried. Enjoy the silence and hopefully you will be banned from this forum.

Now your sounding like a politician that knows he's wrong......Haha

Posted By ICFHybrid on 10 Mar 2014 11:41 PM

As for efficiency I'm not going to even go there because their SEER/HSPF/EER/COP ratings are listed on the manufactures websites.

Maybe we should wait and see how the Carrier unit you are promoting stacks up against the installed base of mini splits.

Here buddy..... Emerson is the first to move forward in there product release cycle .... other compressor manufactures to follow Emerson's foot steps .........
http://www.youtube.com/watch?v=69zvzWA-vBk

http://www.youtube.com/watch?v=XhI711bJbgQ

Maybe you don't realize that Emerson is not the first with variable speed technology. Other manufacturers have had it for years. In fact, Daikin had the first US residential install 5 years ago, back in 2009. What took you guys so long?

Hmmmm....Emerson Climate Technologies.....you're not from St. Louis by any chance, are you?

Posted By ICFHybrid on 12 Mar 2014 06:59 AM
Maybe you don't realize that Emerson is not the first with variable speed technology. Other manufacturers have had it for years. In fact, Daikin had the first US residential install 5 years ago, back in 2009. What took you guys so long?

Hmmmm....Emerson Climate Technologies.....you're not from St. Louis by any chance, are you?

It flew right over you again ... maybe someone else will explain the implications to you.

It flew right over you again ... maybe someone else will explain the implications to you.

Feel free to explain this Emerson Climate Technologies marketing video to the whole board.

I watched the whole clip and wasted my time watching an Emerson rep talk about how variable speed was innovative technology. It was even more interesting when the rep stumbled around talking about how they can now deliver heat at temperatures down to 0F or 5F. Other manufacturers deliver heat down to much lower temperatures.

I'd like to see actual figures comparing the efficiency and cost of mini-splits to a single, inverter driven, ECM fan, well sized (low pressure), short run, conditioned space, well balanced ducted system in a house with many rooms.

Studies have been done with reasonable numbers of ductless minis. Do any reasonable number of such ducted systems exist? Maybe that is what's holding it up?

hate to seem like I'm shilling for another website, but there are numerous articles on green building advisor.com about minisplits by people who have been using them.

Posted By Lbear on 12 Mar 2014 12:29 AM
Green Building Advisor Articles on Ductless Mini-Splits:

GBA1

GBA2

GBA3

GBA4


Please read these scientific articles written by professionals and please stop with the aspersions you are making against forum members. We can have a discussion and even disagree but you really need to tone it down if you are going to be taken seriously here on this forum.

I am not sure if the articles would be classified as scientific.  The first one just talks about complexity, but no real data.  The others are just about individual homes.  I am sure that if have a 1232 sq ft home with 12" walls and R60 ceiling and R50 walls, you could probably use a simple space heater to heat the whole house, so I am not sure how this is really relevant to some of the things being discussed.  In one home, the guy said he needs to wear a sweater in parts of the house.   I think if I need to wear a sweater, then it isn't working as well as i want.  The last one describes retrofit issues, and it would be good for places where you don't use rooms and whatnot.  I am not sure that is workable for everyone.

Posted By jonr on 12 Mar 2014 10:04 AM
I'd like to see actual figures comparing the efficiency and cost of mini-splits to a single inverter driven, ECM fan, well sized (low pressure), short run, conditioned space, well balanced ducted system in a house with many rooms.

Like anything, the air handler placement and ducts in the conditioned space must be carefully designed, and if so will deliver Great Efficiency along with an High-End Comfort Level.

If you watched the Emerson video the 25 SEER compressors are coming very soon to the High-End Ducted American HVAC manufactures.

With net in hand I could have saved my lunch money stepping into this food-fight! :-)

In new construction it's fairly easy to design for heating small to medium sized houses solely with ductless by keeping the whole house heating/cooling loads low, and keeping the loads of rooms doored off from the ductless heads/cassettes lower. When improving the building envelope's thermal performance at the design phase, and utilizing a lower-cost methods, going 1.5-2x better than code for assembly U-factors + ductless on a 2400' house can often be cheaper than going with a bigger-deal 4-5 ton variable-speed ductless solution applied to a code-min 2400' house. And a higher performance envelope buys more comfort than any ducted air delivery heating solution. And even a 9 HSPF/ 18 SEER unit half the size (most better-class mini-splits do better, some multi-splits do too) is going to use a lot less annual power than a 14 HSPF/28 SEER system covering 2x the load, for a number of reasons that aren't specifcally related to the efficiency numbers. (eg: the fact that the heating/cooling balance point is lower in a high-R house, at 55F-60 outdoor temps the cooling loads can be managed by operable windows instead of the heat pump.)

In retrofits it's a mixed bag, I personally know several people in US climate zones 4C, 5A, & 6A who have retrofitted ductless (in house sizes from about 1000 square feet to about 3500 feet, in homes built from 1890 to 1995) who are quite happy with how well it worked out. YMMV.

I also have been helping some folks in US climate zone 5 deal with their recently installed a variable speed 4 ton ducted system (Lennox XP25-048 married to a CBX32MV-048m air handler, set up as 3 zones) who are less than thrilled with the performance. A sub-optimally designed & executed duct system can bring even the best systems to their knees. They got the heat-distribution that they wanted by going ducted in their 18th century barely-insulated house, but they also got the duct losses (and lower capacity at temps under +15F) and air-handler driven infiltration that they didn't want, since the air handler and ducts are almost all above the insulation in a vented attic. As-implemented it's burning at lot more auxilliary resistance power than it should, and the infiltration has made the conditioned space air much drier than when they were running with oil-fired hydronic baseboard heating backed up with a high-mass wood-burner. They would have been better of in this instance with 2.5-3 tons of ductless and a few electric cove heaters for temperature balance in a few rooms- it would have been cheaper up front, would keep up with the heat load (it hit negative double-digits a couple of times this winter despite a 0F outside design temp), and it would use less power than what they got. Again, YMMV.

I'm sure theirs isn't the typical installation, but I'm just as sure that it isn't rare. With any ducted system much of the as-used efficiency is in the hands of the system designers & installers. I'd give this contractor a C on design, D on implementation. The SEER and HSPF numbers under standard test conditions with presumed installation parameters are at most HALF the story for figuring out the true as-installed as-used efficiency of any ducted system. None of it is idiot proof- certainly ductless isn't idiot proof either, (the idiots get more creative every year- there must be a Khan-Academy online course on "creative idiocy" out there or something! :-) ), but there are several more ways to screw it up with a ducted system than with ductless.

Bottom line, the efficiency numbers only apply to near perfectly designed & implemented systems. If history is any guide there's good/better/best, but perfection has yet to be discovered. I'm sure that there are some ducted variable-speed systems hitting near their numbers, but I'd be a bit surprised if the "typical" implementation for any of the better class ducted air source heat pumps actually outperformed or even broke even with the typ for best-in-class ductless. But they're all getting better over time.

BTW: The NEEA Northwest Ductless Heat Pump project has done a lot of in-situ performance  monitoring of real-world installations in climate zones 4C, 5B, and 6B in older stock not superinsulated housing, as well as compiled satisfaction survey data of those who live  in those houses.  Only on of the retrofitted ductless systems I have personal connection to involved better than code construction (the rest were all substantially sub-current-code.) It works just fine for houses that don't have anything LIKE foot-thick walls, R60 attics and triple-pane windows, when properly sized & implemented.

There are no idealized "one solution suits all" approaches- everything is a compromise, but it's silly to think that mini-splits only work in super-insulated buildings- it's one of the most common solutions in Asia, where the average house isn't anywhere near IRC 2012 code min on thermal performance.

Here is a link where a major international HVAC componete manufacture explains the pros and cons of mini splits. Their views are no different than mine that I have been expressing here and being abused for my views.

http://www.ac-heatingconnect.com/wa...ditioners/

"There are no idealized "one solution suits all" approaches- everything is a compromise, but it's silly to think that mini-splits only work in super-insulated buildings- it's one of the most common solutions in Asia, where the average house isn't anywhere near IRC 2012 code min on thermal performance."

Of course the IRC 2012 may not permit use of mini splits as a central heating system in a code minimum house.

Inadequate heating in very cold conditions is the largest customer issue. Fourteen
percent of surveyed participants stated that their DHP had failed to provide adequate heat
at temperatures less than 10 to 30 degrees. This issue was not isolated to specific climate
zones or DHP models.

I'd like to see more explanation of this paragraph. It may be a heat distribution issue.



There is no doubt that more insulation reduces the number of heat sources needed and benefits ductless designs.

If you want cost is no object efficiency, then use geothermal and radiant. But at some point, insulation and PV solar make more sense than the actual efficiency of the heat production and delivery. And of course up-front costs matter.

Posted By joe.ami on 14 Mar 2014 10:16 AM
"There are no idealized "one solution suits all" approaches- everything is a compromise, but it's silly to think that mini-splits only work in super-insulated buildings- it's one of the most common solutions in Asia, where the average house isn't anywhere near IRC 2012 code min on thermal performance."

Of course the IRC 2012 may not permit use of mini splits as a central heating system in a code minimum house.

That really depends on the design code-min house, and the number/placement of the heads, methinks.  In new construction you have control over that.

BTW: Where in the IRC does it specify the central heating requirements?