What is the advantage of minisplits versus window units? It has even less plumbing and duct work. It should be even cheaper.

We use minisplits for heating and cooling. Sounds like they have residential construction issues in Taiwan. That doesn't affect how we use minisplits here.

Posted By ba_icf on 16 Mar 2014 11:32 PM

That might be the case, but the reality is that everyone in Taiwan uses minisplits, and the temperature is not very good.  I am just visiting, so I am not trying to analyze why it isn't working.  Usually, the buildings have very little insulation.  They are usually made of concrete.   I just turn it on to a certain temperature, and it is usually not very comfortable.  Usually, it is still humid in the room, and the unit is blasting cold air.  All I know is that I don't like it, and they aren't doing what they are supposed to well.

It might not be the fault of the unit, but to say that they use them in Asia, so that means that they work is not valid.  They are used in Asia because it is their only option.  They can't use central A/C for most units.  They all live in condominiums made of concrete with no space for ducts. To me, it is just a fancier window unit with a dedicated hole in the wall instead of using a window.

What is the advantage of minisplits versus window units?  It has even less plumbing and duct work.  It should be even cheaper.

Well said ba_icf

Glad we have A FEW people here that understand how product marketers skew reality  .... If you have basic building science knowledge, or just a bit of common sense, you can see through the deception in most cases.

Posted By ICFHybrid on 16 Mar 2014 11:43 PM

What is the advantage of minisplits versus window units? It has even less plumbing and duct work. It should be even cheaper.

We use minisplits for heating and cooling. Sounds like they have residential construction issues in Taiwan. That doesn't affect how we use minisplits here.

Most of Asia that I have visited is built in the same manner.  Concrete, high rise, multi owner buildings.  When you purchase a new unit, it is just bare concrete walls.  The buyer needs to supply everything else.  This experience is from Taiwan and southern China.  Maybe, it is different in other parts of Asia.  My wife's family has bought units in both places.

I just did a quick search, and I found window units which heat and cool.  Cost less than than $1000.  The solution that approaches $1000 is for 24,000 BTU cooling, 16,000 heating.
Most of the units are less than $500 for 7000 BTU cooling 3500 BTU heating.

http://www.livingdirect.com/window-air-conditioner-heater/Home_Air_Quality-Window_Air_Conditioners-Heat_And_Cool,default,sc.html

So, it has the heating and cooling functions.  It doesn't have the separate compressor unit.  It is cheaper.  Why would you use minisplits over this super simple, super inexpensive solution?  It is definitely a DIY project.  The unit is much cheaper.  The labor is much cheaper, e.g. support it and give it electricity.  The warranty covers the unit which is most of the issue.  No extra refrigeration lines.  No connecting all of the blower units to one compressor.  I think if people are pushing cost and ease of installation, then I can't see how you can beat these window units.

I don’t think anyone should just outright dismiss mini splits as not being a good solution for some applications. Granted, mini splits are complicated devices that the average DIYer would not be able to completely install, maintain and repair. We prefer devices that DIYers can easily install, maintain and repair. However, mini splits do have real merit in some markets and situations. The mini splits that we observed first-hand in Taipei, Taiwan appeared to be first-rate and worked very well. However, the mini splits that we observed were also installed in high-end hotels and office buildings. We are not surprised to hear that the mini splits in the more typical Taipei residences don’t work nearly as well. Residential construction in Taipei ran the entire gamut from very shoddy to high-end when we last visited. So there is much construction diversity in Taipei and making a generalization here is likely not a good bench mark. We have very fond memories of working and playing in Taipei and we greatly enjoyed the people, weekend flower/jade market under the bridge, the numerous night markets and shopping, and the steamed dumplings at Din Thai Fung.

We totally agree with the comment that one shouldn’t put much credence with regard to a high post count being indicative of expertise. The better forums don’t even enable the post count feature as research has shown negative correlation with post count and expertise. Enabling the post count feature also creates an environment that encourages power posters…folks who toss out a sentence of gibberish just to improve their post count to create a false impression of their expertise. Each statement made in a post should stand on its own merit no matter how many posts that poster has made.

Why mini splits instead of window units… Mini splits get the noisy compressor unit out of your living space. Window units take up your window space and can look trashy. Mini splits have a higher COP than window units. Window units had about 1/3 the service life as mini splits the last time I checked. A ROI analysis on the actual units you are considering will address the $$$ consideration.

ICF if you recall my comment was about a specific comment where Dana mentioned Asian homes of less than our code minimum. Please do not accuse me of red herrings when you take my comments out of context.

Posted By ICFHybrid on 16 Mar 2014 10:54 AM

a single headed minisplit would not likely heat a code minimum house to required standards.

Joe, that's a red herring that you like to throw out. None of us have ever claimed that a single mini split is likely to do that in code minimum. Except, maybe, badger's buddy, Little Ricky there. He continues to hold that ductless minis are for cheap construction, completely ignoring the fact that they are, instead, excellently suited for quality construction.

Well, I actually implied that it might be able to meet spec on an IRC code min home. Based on existence proofs in retrofits in US climate zone 4 where the spec can easily be met with nowhere near the 88F overheating issue mentioned by jonr.   I have a relative living in climate zone 4C in a home substantially below IRC 2012 levels who could get there with the doors closed at sub-80F temps in the common area, but instead opts to use supplemental resistance heating in the remote rooms for a few hours during design-day overnights instead. Without the resistance heating the temperature deltas at design condition are less than 10F with the doors closed as-is. It would just be silly to turn up the mini-split to a bit above 75F to be sure to not drop below IRC 2012 section 303.9 spec in the bedroom, but there is no question but that it would make it.  The house in question has a code-min sized window for egress in the doored off bedroom, and similarly small windows in both of the doored off bathrooms. The rest is fairly open, and stays within 5F of the room with the ductless head.

Clearly the climate matters- I've acknowledged that it gets to be a bit tougher north of climate zone 5, and may be too constraining to get there strictly at code min with just 1-2 heads and no resistance heating, even with a pretty-good floor plan for point-source heating. At IRC 2012 levels the room to room temperature differences can be pretty limited if you design the floor plan optimally. IRC 2012 is a bit better than the homes most of us live in, and dialing back window losses and exterior wall area in the doored off rooms can make significant reductions in the heat loads of those rooms without going better-than-code.  (As a design exercise I've only run the numbers for higher-R homes though.)

And I freely admit my bias toward higher-performance building envelopes over higher-performance mechanical systems, since performance buildings have a longer lifecycle than performance mechanicals and buy more comfort.  Point source heating only really sucks if you're living in a crummy sub-code house with sub-optimal layout (like mine).  But a 3-head/cassette system can handle most mid-sized code-min houses if laid out reasonably, if the house design is constrained to 1 or 1.5 stories. 

I could easily fully condition my ~2400'  1.5 story 1920s antique in climate zone 5A (99% design temp +5F) with three heads without having to roast any of the zones to make R303.9 in the doored-off rooms, even without bringing the envelope up to IRC 2012 levels.  If the price of natural gas gets way ahead of electricity I just might, but for now it would be pretty much a wash on operating costs.  In the meantime I just keep upgrading the envelope in fits & starts, on a "most economic" basis as things get repaired or rehabbed. The only part that currently beats IRC 2012 on this house is somewhat better than code basement insulation (and possibly the air-tightness, though I haven't measured air leakage recently enough to say for sure.)  Clearly your mileage may vary, but on new construction at IRC2012 R/U values it needn't vary by much.

On way-better-than-code homes I've dealt with it almost didn't matter where the ductless heads were, as long as there was one per floor, with no more than one door between the ductless and a conditioned space, with some consideration toward keeping the doored off loads low, and designing the ventilation flow of the HRV system to supply the doored off areas from the common area via jump ducts for a very modest improvement in temperature balance.

I doubt the comfort levels in ba_icf's low-end Taiwan housing straw-man example wouldn't be dramatically improved by using ducted HVAC solutions.

But I'm positive putting some cash toward improving the building envelope would, even it it's still way below US code-min. (The way it is in some pretty-comfortable houses I've slept at in Japan and Korea that were point-source heated.)

Cheap PTHP solutions have been looked at by some performance-home builders building on speculation, but nothing says "cheap" like a noisy PTHP, and I suspect going that route takes more off the final sales price than the installed cost delta between a PTHP and a decent mini-split, so I doubt they've really saved much by going that route. I've yet to see a PTHP unit that fully cuts it at design temp in zone 6 & 7 climates though, but in most PassiveHouses it doesn't really have to- the thermal mass of the house and high-R takes it through the peak load hours.

Posted By Dana1 on 17 Mar 2014 04:30 PM
I doubt the comfort levels in ba_icf's low-end Taiwan housing straw-man example wouldn't be dramatically improved by using ducted HVAC solutions.

But I'm positive putting some cash toward improving the building envelope would, even it it's still way below US code-min. (The way it is in some pretty-comfortable houses I've slept at in Japan and Korea that were point-source heated.)

Cheap PTHP solutions have been looked at by some performance-home builders building on speculation, but nothing says "cheap" like a noisy PTHP, and I suspect going that route takes more off the final sales price than the installed cost delta between a PTHP and a decent mini-split, so I doubt they've really saved much by going that route. I've yet to see a PTHP unit that fully cuts it at design temp in zone 6 & 7 climates though, but in most PassiveHouses it doesn't really have to- the thermal mass of the house and high-R takes it through the peak load hours.

Now that's a disrespect of someones personal experience if I have ever seen one...

There are 3 basic levels of quality.

1. Window units - Bottom of the barrel
2. Mini Split Systems - A step up in efficiency from a window unit, but again has all the air quality issues like the window units and etc .... and of course, is still an Eye Sore
3. Ducted Systems - High End system which addresses overall envelope Comfort, and air quality issues, with Efficient operation cost.
   

Where's the disrespect there?

All I'm able read into it is my bad grammar- I need an editor- what a garbled hack of a sentence, with multiple negatives that invert the intent, to be parsed in multiple ways! :-)

The comfort issues in substandard housing are far more about the building envelope than the mechanicals (that may or may not be able to keep up with the loads.)

And there's no inherent stamp of quality that goes along with "duct". I live in sub-code housing with ducted air conditioning, and I can say that from personal experience that the ducted AC at my house isn't exactly the signature of comfort or quality, and nowhere near the quiet-comfort of mini-splits in some of my relatives' houses. Of course if you'd likely argue (correctly) that my existing AC system isn't a sufficiently "High End system..." to meet that comfort & quality standard, eh? :-)

In fact it's more comfortable to cool my house with 1-2 window AC units, but not so much so that I take the time to put them in & take them out. It's easier to just install ear plugs, bump the T-stat down until the humidity monitors are reading 45%, then turn it off. I s'pose I could install dehumidistat control, but my AC loads just aren't high enough often enough to make it worth my time.

Concrete construction in Taiwan and tropical Asia is prone to high latent loads independently of the sensible loads, due to the high vapor permeability and moisture wicking/storage characteristics of the construction. That isn't going to be fixed with ducts, but it can be fixed by using better construction techniques. It's not a mini-split problem per-se, and not improvable by ducts, but it's a soluble problem. But until the market demands it there is little incentive to change. Even a high-end variable speed ducted system doesn't really deal with those deficiencies well, and certainly no better than a Daikin Quaternity would.

Posted By Dana1 on 17 Mar 2014 04:30 PM
I doubt the comfort levels in ba_icf's low-end Taiwan housing straw-man example wouldn't be dramatically improved by using ducted HVAC solutions.

But I'm positive putting some cash toward improving the building envelope would, even it it's still way below US code-min. (The way it is in some pretty-comfortable houses I've slept at in Japan and Korea that were point-source heated.)

Cheap PTHP solutions have been looked at by some performance-home builders building on speculation, but nothing says "cheap" like a noisy PTHP, and I suspect going that route takes more off the final sales price than the installed cost delta between a PTHP and a decent mini-split, so I doubt they've really saved much by going that route. I've yet to see a PTHP unit that fully cuts it at design temp in zone 6 & 7 climates though, but in most PassiveHouses it doesn't really have to- the thermal mass of the house and high-R takes it through the peak load hours.

I am not sure that it is a straw man example.  I have stayed at NTU - national taiwan university's hotels.  One is fairly new, less than 5 yrs old, and the other seems pretty new, probably less than 20 yrs old.  Based on the bathrooms, e.g. glass shower on rollers, trench drains, very large showers, european faucets, etc., it is probably not considered a low end hotel.  I would say it is above average because it has quite a few westerners staying there.  My wife's family also has a fairly new unit, i.e. less than 5 yrs old, and it is in Taipei, and it is probably above average.  It has underground parking with elevators for the cars, so that they can stack cars 2-up.  One owner has a mercedes, an audi, and a porsche, so it is probably a relatively high end building.  It is also close to the university and a train stop.  I am sure the units cost over $1 million US, so I don't know how low-end that is in your part of the world, but it isn't low end in my opinion.

My uncle's unit is even more expensive, but his unit is more comfortable due to the direction of his unit.  I haven't stayed at his unit in the winter.  However, it is still built out of concrete with very little or not insulation.  However, whenever it does get hotter, the humidity is always present.  Maybe, he doesn't turn it on long enough, but the temperature is very low, but it is still very humid, so it feels like a clammy cold.

I only have those few experiences.  I am sorry if they are straw man examples.  When it gets hot, I turn on the AC.  The temperature gets lowered, but it becomes too cold.  I turn it off, it gets hot very fast.  I turn it back on, it gets cold very fast.  It is just like a window unit to me.  There is a temperature setting, but the air is usually too cold, so I don't like to have it on automatically.

Typical zoned ducted central air systems have there distribution problems when CFM ramps down to accommodate low demand. Their are some solutions but manufactures have yet to address the problems fully. Found a few third party half baked solutions that would help but nothing solid.

I really wish the high velocity central air system manufactures which are few, would dump some serious dollars in more R&D and get there products up to date, and expand there offerings. As they could be a serious competitor in the high end market providing solutions for high performance envelopes.

hey could be a serious competitor in the high end market providing solutions for high performance envelopes.

Why would they? It's a dead end street. The higher performance your envelope, the less heating you need.

Posted By ICFHybrid on 18 Mar 2014 12:04 AM

hey could be a serious competitor in the high end market providing solutions for high performance envelopes.

Why would they? It's a dead end street. The higher performance your envelope, the less heating you need.

If you knew what the CFM output is per TON on high velocity central air systems, you would delete your misleading ignorant post.

Their units are rated at about 250 CFM per TON, about half that of your typical American air handler ..... they have issues, they just need to re-engineer their product to adapt to new high performance home designs.


Here's one idea of expanding their bolt on product offerings .... How about a ceiling register vent in which appears to be a small single vent, but in reality it serves as the ERV or HRV fresh air exhaust and conditioned air vent.
By the way, I hold that patent .... Haha

If you knew what the CFM output is per TON on high velocity central air systems, you would delete your misleading ignorant post.

No, probably not. As envelopes improve, the heating and cooling requirements improve, too. At the extreme, you get homes that can be heated with a very small amount of heat. The smaller amount of heat you need to move, the smaller the amount of air you need to move it. At some point you get down to low velocity ventilation systems which move far smaller amounts than ducted heating systems.

I hope you didn't spend too much time on the patent.  I don't see much need for a combo vent.  And, I hope you at least used a spell checker on the application.

Virtually everything in HVAC is moving the other way from high velocity.

We would agree Joe. Tighter, better insulated buildings require less heat. HR heating and taking advantage of PS heating is becoming more common in new construction and don't require ducts. So just meeting ventilation requirements is starting to become the only reason to move air. However, it will likely be some time before we see the end of furnaces in tract homes. At least keep the ducts within the conditioned living space.

Ricky,
I was hot to try high velocity ducted systems when they first arrived at the trade shows long before mini-splits were available.  I saw the possibility of using thinner floor structures for the ducts, etc.  But later on, after visiting some homes with this type of system and hearing about the problems caused by the installers and the higher cost, I backed off.  My hope is that the system and installers will improve enough for me to consider high velocity again.  As a designer and building consultant, I want more options on the table to meet various and unusual home designs.  Although I think mini-splits are great, most of my clients still prefer the central systems primarily because of aesthetics.

Although I think mini-splits are great, most of my clients still prefer the central systems primarily because of aesthetics.

I think people gravitate towards what they grew up with and what they are accustomed to. What I have been seeing is that when people are introduced to something new (and better), they tend to like it and that allows their world to change a little.

Posted By ricky_005 on 18 Mar 2014 12:16 AM

If you knew what the CFM output is per TON on high velocity central air systems, you would delete your misleading ignorant post.

Their units are rated at about 250 CFM per TON, about half that of your typical American air handler ..... they have issues, they just need to re-engineer their product to adapt to new high performance home designs.


Here's one idea of expanding their bolt on product offerings .... How about a ceiling register vent in which appears to be a small single vent, but in reality it serves as the ERV or HRV fresh air exhaust and conditioned air vent.
By the way, I hold that patent .... Haha

The key word words where "they have issues, they just need to re-engineer their product to adapt to new high performance home designs"  That could mean a low velocity central air system or what Ever..... G