AC_Hacker installs a new Mini-Split

[AC_Hacker]

I installed my original mini-split in around 2009, before I started my Homemade Heat Pump Manifesto project. The heat pump I installed then was a Sanyo KS0971 (+ C0971
+ CL0971). It had what I considered to be a respectable SEER rating. I didn't know as much about these matters at the time, so it seemed like a reasonable choice. Over the years, it has been an extremely reliable performer, kept me comfortable, and saved me a lot of money, compared to the more conventional heating & cooling systems. However, last winter, it went into serious decline nd failure. I have decided to replace it.

I have learned quite a bit about these matters in the intervening years. One thing I learned is that the salesmen & saleswomen don't know as much as they should to properly advise a customer. Of greatest importance to me was that They only mentioned SEER ratings to denote quality. None ever mentioned the rating HSPF (Heating Seasonal Performance Factor). SEER ratings are of greatest concern when the cooling performance of the mini-split ids of greatest importance. Likewise, HSPF ratings are of the greatest importance when heating is the primary concern. I have learned that SEER ratings and HSPF ratings are not necessarily related, and that a higher SEER does not necessarily indicate a higher HSPF, and vice versa.

So, this time, I did not shop for the best price, but for the highest HSPF, because my concern is for heating performance, and now also with a keen eye on the burden I place on the environment

The model I ended up choosing is a Fujitsu Halcion Model AOURLS3, rated at 3/4 Ton ((9,000 BTU). It was the very best I could find. My house is small and very well insulated, and this size works just fine.

As a comparison, my old Sanyo had the following specs:
SEER = 16
HSPF = 7.7

The new Fujitsu has the following specs:
SEER = 33
HSPF = 14.2

With regard to the HSPF ratings, they can be expressed as COP (Coefficient of Performance) by dividing the HSPF number by 3.12

So the old Sanyo had a COP of 7.7 / 3.12 = 2.47 (pretty good)

the Fujitsu has a COP of 14.2 / 3.12 = 4.55 (jaw dropping performance!)

The amazing performance does NOT mean that I will get more heating or more cooling, but it does mean that the power this Fujitsu uses will be much smaller. I'm less impressed by the lowered cost of energy it consumes, as I am by its greatly reduced load on environmental resources, and a lessened impact on the climate crisis.

It is also interesting is that the Sanyo cost $1300 ten years ago, and the Fujitsu cost $1600 today.

Quite a bargain, I think.

[pinballlooking]

Nice specs. That should serve you well.
That is a Great COP number.

[Daox]

Very interesting performance and price comparison. I wonder what things will be like in another 10 years.

[MN Renovator]

I've been looking at installing this model on my house but instead going with the 12k BTUhr unit to better cover a majority of the cooling needs instead of replacing my slightly oversized 2 ton(a 1.5 ton would be perfect for my house) central air unit. If I put it in my bedroom and aim it down the hall, it would cover the upstairs for a majority of the days and I'd still use the central air here and there to spread the cold air through the rest of the house and cover design days, likely 2 hour runtime at most on hottest days.

In the winter, I plan to shut the bedroom door, keep the rest of the house cooler and use the mini-split to specifically heat the bedroom to a comfortable temperature while I'm on the computer, watching tv or sleeping. Normally during the workweek I'm usually in the bedroom most of the time anyway and during the weekend I'm often not home for a good chunk of the time and spend more of the time in the bedroom anyway. It seems this unit is one of the best for this type of use. I've also looked into the comparable Mitsubishi and Panasonic units as they have progressed in HSPF, SEER, and 17f heating performance numbers, it seems they swap around with who performs the best. I think that Daikin, Mitsubishi, and Fujitsu share the role in the most reliable equipment and are all great choices, but I'm looking to buy based on performance and Fujitsu is there right now.

Can't wait to hear about how it performs on the coldest nights of winter for your home.

[pinballlooking]

I don’t have one of those brands but I do have inverter tech in my bedrooms. They can be over sized and work very well in the bedrooms. In three bedrooms here two of them are over sized 9K units but the inverter units still works very well.

That COP is getting real close to GEO.



Mine is Tranquility 30 Q-Digital Series

[AC_Hacker]

Originally Posted by pinballlooking

....They can be over sized and work very well in the bedrooms. In three bedrooms here two of them are over sized 9K units but the inverter units still works very well.

Yes, they will work well. But if the situation is such that if you can plan for it, slightly undersizing will be more power efficient.

That COP is getting real close to GEO.

That is why it is so jaw-dropping. In this area, the COP exceeds previous GSHP units. The HSPF is based on a yearly average. And it's obvious that when outside temps go down, COP will also drop, the more "lifting" the unit has to do, the lower the COP.

I think that if the same attention was given to GSHPs as has been given to ASHPs, there would be big improvements there too. The physics of extracting heat from deep ground contact is absolutely better than extracting heat from ambient air. It's a matter of refinements, in my opinion

I'm fortunate to live in an area with fairly mild (low 40s to mid 30s), usually even winters. Which favors ASHPs. However, occasional dips, when an Alaskan cold front drops temps to low teens, for a few days, then the ASHPs are working hard.

-AC.

[Fionn]

Any updates on the installation or performance?

[AC_Hacker]

Originally Posted by Fionn

Any updates on the installation or performance?

Thanks Fionn,

I have been meaning to follow up on the Fujitsu install.

First, to answer your question, the Mini-Split works very well. It's not easy to verify the claim of efficiency with an Air-Source & Air-Delivery unit. But I'm watching my electricity bills, which won't be easy to isolate any performance specs, since I drive an electric car, charging only at home, and I have a house mate who uses varying amounts of electricity.

OK, now with the disclaimers over...

My last Mini-Split was a Sanyo, and the specs were not stellar, but it was very reliable and cut my heating bills for about 10 years. The operation sound of the outside unit was pretty modest, considering that this was the machine that heated my house, and the inside unit was virtually silent. I had to look for an indicator light to know if it was running.

The Fujitsu has much higher efficiency specs, but the same output specs as the Sanyo, so I think that comparisons are interesting. First of all, the outside unit was somewhat larger in size, taller, wider, and deeper. I also noticed that the fins were more densely spaced than the Sanyo. The inside unit was also larger in the same manner, including fin density. In operation, the Fujitsu is again very quiet, but the fan is passing more air through the fins, so I can hear it, but just barely when it is running.

The remote control/room temp sensor is much less cluttered on the Fujitsu than the Sanyo, but it offers the same options, including timer controlled on and off. But it has an additional feature that is amazing, I has an occupancy sensor. This means that the heating tapers down when the room is empty, and likewise it tapers up to desired room temperature, when someone is in the room. I'd estimate that the range of degree change is about 8 degrees max from bedtime to dawn, but during day use, the swing is less. But the changes are very gradual and comfortable. One curiosity is that If I'm sitting on the couch with my gal, watching TV, the Fujitsu thinks we left the room... in a way, I think the Fujitsu is correct. This feature is available with a button on the remote, and can be turned on or off. I turned it off for a day or so, and then turned it back on. However, it didn't seem to be working at first when switched back on. But over time it returned to it's previous mode. This make me think that there is some kind of 'learning' algorithm that controls aspects of performance. It works so well, that I haven't bothered to program on/off cycles, since it does it so well automatically.

In short, once I got over the "new", the Fujitsu has disappeared, and left me with a comfortable home.

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Regarding installation, there are so many well documented installs on this site, that I didn't think mine would add any value.

However, I did reuse the old line set, and saved some money there ($120). Looking back, I took a risk that seems to be OK, and that risk was that I used the old flares at the ends of the old line set. During the install (but after the fact), I did learn that soft copper, which is what line sets are made of, have a definite limit to bending (5 times) that they are exposed to, before they become brittle. Since I installed the Fujitsu exactly where the Sanyo was, I expect no problem. BUT the flares themselves are exposed to significant flexing when they are formed, which could make them approach brittleness, and my reusing the same flares was not the wisest thing to do. Looking back, I wish I had cut off the old flares and made new ones. I have the equipment, I just didn't have the knowledge.
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Best Regards,

-AC_Hacker

[Mikesolar]

Originally Posted by AC_Hacker

Thanks Fionn,


Regarding installation, there are so many well documented installs on this site, that I didn't think mine would add any value.

However, I did reuse the old line set, and saved some money there ($120). Looking back, I took a risk that seems to be OK, and that risk was that I used the old flares at the ends of the old line set. During the install (but after the fact), I did learn that soft copper, which is what line sets are made of, have a definite limit to bending (5 times) that they are exposed to, before they become brittle. Since I installed the Fujitsu exactly where the Sanyo was, I expect no problem. BUT the flares themselves are exposed to significant flexing when they are formed, which could make them approach brittleness, and my reusing the same flares was not the wisest thing to do. Looking back, I wish I had cut off the old flares and made new ones. I have the equipment, I just didn't have the knowledge.
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Best Regards,

-AC_Hacker

Hi AC. I haven't been on for a while but since you bought a Fujitsu, I take some notice partly because that is mostly the brand I install. You got a good price on that one.

As for installation, I now pressurize the linesets to 500psi and hold for few hours. It really prevents callbacks. I wouldn't worry about cutting off the flares and starting new. They are all made to the same standard anyway.

I have one of these units (12000btu) on test now and I have adapted it to heat a tank of water. I've just started so I won't have any real impressions of it for a while yet.

I hope it last at least a decade.

[Mountaintop]

Mikesolar - I would be interested in seeing your setup on how you connected the Fujitsu to a storage tank. Are you using the lineset to steal heat from the system when in heat mode or did you put a heat exchanger on the discharge of the compressor? What water temperatures have you attained? What have you been using the water for?

Thanks,
Matt