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American Standard vs. Fujitsu heat pumps

Jonny_H | Posted in Mechanicals on

Wondering if anyone has experience with or access to detailed performance data on American Standard heat pumps….

(Still) trying to figure out HVAC on my remodel situation (zone 5).  Manual J (done by Energy Vanguard) puts my loads (in btu/h) at:
2nd floor:  10k heating / 5k cooling
1st floor: 14k heating / 12k cooling
Basement: 9k heating / 0 cooling (with the unrealistic condition of being uninsulated & unfinished but fully conditioned — I’ll either insulate, or accept the basement being colder, or both.)  I also went conservative on these load calcs, derating my exterior polyiso to R-5/in.

The 2nd floor (with 2 bedrooms, a bathroom, laundry, and a study open to the staircase & hallway) I’ve been seeing as a pretty good match to a Fujitsu 9k mini-ducted unit (ARU9RLF / AOU9RLFC).

The 1st floor (mostly open, but with a bath, bedroom, and office off to one side) could be handled a couple different ways.  My gut says a 15k ductless (15LZAH1) would be fine and probably carry the whole house in most conditions — in a past question I posted, Kyle R described a very similar setup that works in his house.  This would likely be the lowest cost (eliminating any ductwork).  Other approaches that would serve the more closed-off rooms on the first floor would be a ducted mini (like the 18RLFCD), or a multi-split with a ductless head in the open area and a ducted head serving the side rooms.  In the first case, the basement would just be indirectly conditioned; the second or third options could provide ducted conditioning to the basement as well.

I’ve delved fairly deep into the Fujitsu data and convinced myself that these approaches seem reasonable; I like Fujitsu because they have good modulation, significantly higher heating output than cooling (matching my load conditions), and they maintain that output at low temperatures (design temp of 5F, and while our winter averages are in the 20s, it seems like every year now we get a polar vortex where it’s below 10 for several days straight.)

I found a local installer and we discussed these options, but he’s kind of down on mini-splits (ducted or ductless) due to poor humidity control compared to his preferred solution, American Standard split-system heat pumps.  He just quoted the following for me:

2nd floor: Fujitsu 9k ductless (~$5000, going ducted as I wanted would add another 3-5k)

1st floor and basement: American Standard AccuComfort Platimum 18 series (4A6V8024A1000C + TEM8A0B24V21DB + AMSHTR1510BRK) (~$11k, plus $2k in recommended upgrades (humidifier and fresh air intake ducted to return, recommended instead of an ERV), plus $4-5k if I want to replace rather than reuse the existing crummy ductwork).

Aside from the pricing being way more than I had been planning on, I’m not sure that the proposed American Standard system really measures up to the Fujitsu, but it’s hard to tell because I can’t find detailed performance data on it.  On the surface, it’s quoted as 18 SEER, 12.9 EER, and 9.6 HSPF — compared to the 18k ducted Fujitsu at 19.7 SEER, 11.3 EER, and 12 HSPF, or the 15k ductless at 25.3 / 13.3 / 13.9 — the biggest differences are in the HSPF, and I’m in a heating dominated climate.  The NEEP ASHP list doesn’t include this specific American Standard unit, but looking at others in the same family, they’re about 86% of nameplate capacity at 47F, and 55% of nameplate capacity at 5F — so that backup resistance electric heat seems necessary, while with the Fujitsu units it probably wouldn’t be.  I’m also not convinced that these units are actually inherently better at handling humidity — the installer was describing overcooling with the air conditioning and then reheating with the resistance heat for humidity control — but again, without detailed data on the units, it’s hard to tell.

So, from a pricing perspective, I’m being quoted somewhere between 16-28k, while I’m looking at pricing online and guesstimating that I could get a ducted 2nd floor, ductless 1st floor, some new tools, and the EPA cert for less than 8k, and leave some money on the table for an actual HRV or ERV, at the expense of my time and voiding the warranty (for whatever it’s worth).  I don’t begrudge tradespeople their time and expertise, but I’m also fast running out of money on this project….  I’ve also invested a lot in my building envelope with the hope of saving money on mechanicals (both capex and opex).

From an equipment selection perspective, I’m not an expert, just have read a lot, but I don’t know if I’m making an accurate assessment with my plans, or if I’m missing something critical.  Likewise, this installer seems like a sharp guy and seems to be concerned about the right things, but I’m not convinced that the equipment he’s proposing is really the best option — in particular, I don’t see the advantage of the american standard split system over a fujitsu mini-ducted, and despite all the caveats of choosing a ductless over a ducted unit, it seems like ductless units are popular and work well for the people who have them.  But, without detailed data on the american standard, I can’t really do an accurate comparison to fujitsu (and honestly while the fujitsu data table is not bad, I wouldn’t mind even more data than they provide — with enough performance data points and some historic weather data, it wouldn’t be too hard to simulate unit performance and come up with kind of a personalized SEER / HSPF rating.)

Now that I’ve written enough to print a small book just of my GBA questions, anyone have thoughts on the above?

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Replies

  1. Trevor Lambert | | #1

    The plan of fresh air intake instead of an ERV is a bad idea. How would you get fresh air to the second floor? How do you get fresh air when heating or cooling is not needed? The heat pump fan could run all the time, but that's not very efficient. And you don't want a ductless upstairs, otherwise you're going to need supplemental heat in the bedrooms.

    In a new house, the best way to get fresh air is with an ERV and dedicated ducting.

    1. Jonny_H | | #7

      Thanks for confirming what I was suspecting -- I already roughed-in some ductwork for an ERV myself too, so why wouldn't I want to go that route? Especially when the upcharge for the fresh air intake was $1000...

  2. mgensler | | #2

    I think you will be very happy with the Fujitsu ducted. Why not put a 9k on the 2nd floor and a 18k hung in the basement to do both the basement and the 1st floor. Both modulate to 3k output on the low end.

    I would spend the money on an engineer to do the manual d. So maybe $2k for design and $20k for the systems based on your numbers.

    I don't think you will need the humidifier with all the improvements.

    The hspf numbers are for zone 4. In your zone the spread between the two systems will be even worse.

  3. Expert Member
    Akos | | #3

    The American Standard unit is not a great fit for Zone 5. The output really falls off bellow 47F and it doesn't look like it comes with a pan heater. If you want domestic, look at the Carrier's cold climate units. The rebaged Midea units sold by Carrier are also a pretty good deal and get similar efficiency as the Fujitsu unit.

    Installing a unit (either ducted mini split or air handler) in the basement as suggest by the installer makes the most sense. $4k for ducting in an unfinished basement seems on the high side especially when just replacing existing. I would see what low hanging fruit there is to fix for reasonable price. Keep most of it, some duct seal mastic over joists and replace any panned returns with rigid.

    I would have to think about the idea of dehumidification with resistance re-heat. It doesn't seem to be the most efficient option.

    A better solution in your case with two units is to set the 2nd floor unit to dehumidify and the main floor unit to heat to keep the place from getting overcooled. This way the re-heat comes from a heat pump. Since this most likely will only happen on a mild day and you don't need a lot of re-heat, the COP of the unit will most likely be above 4.

  4. Kyle R | | #4

    So as you mentioned, I have a ductless Fujitsu on the first floor and ducted on the second. Having a ductless unit on the first floor gave me a pan heater on the unit that does all of the heating. But doing it over again, I would have gone with a ducted carrier unit on the first floor with a pan heater. The bonus of not seeing the head and having a regular furnace filter to change would be worth it to me.

    I did install both units myself (including ducting) up to the point of pressure testing and vacuuming the line sets, I paid a local contractor $200 to do this. If you have more time than money, it might make sense for you to install a ducted unit upstairs first (I assume this ducting is short and straightforward) and then evaluate if the downstairs is too big for you to tackle?

    I am installing an Ultra-Aire MD33 for dehumidification. My cooling load is so low, I don’t think any AC equipment would have dehumidified adequately.

    1. Jonny_H | | #10

      I feel you on the having a regular filter thing -- that seems to be the one big weakness of ductless units to me. My wife grew up in a country where everyone has ductless units, so the visual impact of a ductless head isn't really an issue for us, at least. Looking at the carrier lineup, though, it seems like there's a step in modulation ability -- the 12k ducted unit can modulated down to 1800 in heating, but the 18k can only go down to 8900. It's really a shame Fujitsu doesn't do 1:1 ducted units with pan heaters!

      1. Kyle R | | #11

        According to Carrier’s literature the 12k modulates down to 4,500 btu/hr vs 5,500 btu/hr for the 18k for heating. Similar numbers for cooling. One other thing to note, the 12k has a static pressure rating of 0.2 vs 0.4 for the 18k unit.

        1. Jonny_H | | #13

          Which Carrier unit are you seeing that on? I was looking at this (https://www.shareddocs.com/hvac/docs/1010/Public/01/01-DLS-058-01.pdf) which shows the 40MBDQ18---3 ducted having a minimum of 8900 and the 12k having a minimum of 1800 -- but I haven't found more detailed capacity tables on their stuff yet.

  5. user-6777635 | | #5

    Not an expert on mechanicals but have done 3 projects with Fijitsu Air Source heat pumps, 2 Passive House levels, but not stamped, and one Pretty Good retro fit around the south and east shore of Georgian B - Central Ontario around 44 to 45 degrees of Latitude . Zone 5 .

    The Passive Houses heat and all in electrical are in the $1000 to $1200 range . The Pretty Good about $1500. Pretty good is almost 10 years old and no service just clean the filter . Hydro One rate are about 21 cents/kWh all in. I think Green Mountain or Vermont PU rate are about 14 cents/ kWh

    We only have used Fujitsu RSL models Extra Low temperature heating. We have skipped ducted ASHP and installed very good, full house ducted ERV / HRVs VanEE and Zehnder . Great air circculation. Easy to install. Zehnder will do layouts for you. On lower levels we use the 12 RSL even though loads would be satisfied by a 9 RLS. The cost difference is few $100 and most of the time the lower unit heats the whole house. The primary cooling unit is on the upper level. Cold air falls - hot air rises . The exterior units are on free standing racks about 3 ft above grade for snow and defrost cycle water runoff .

    All homes have electric baseboard backups that rarely is used but covers the odd -40 C event and a Mom that wants extra heat for new baby's bedroom .

    $5000 iinstallation is over priced but hear about quotes of $6000 . Takes about 6 hours for a trade install ie $700 to $800 plus about $600 of supplies plus the units. Our electrican installs wiring to the outdoor unit

    Bob F

  6. Walter Ahlgrim | | #6

    If I were buying another hear pump I would avoid the ones that blow air out the top.

    The problem I have with my Rheem HP is from time to time I get freezing rain when we do ice will form on the fan blades sometimes the ice will bridge the gap from blades to the shroud preventing the blades from moving stopping the air flow in turn stopping the flow of heat into the house.

    It is not an everyday problem but it is a pain to get out of bed and walk on ice in the rain and poke at the fan to free it.

    My HP works great with the strip heat locked out above 8°F.

    Walta

    1. Jonny_H | | #8

      Hm, that's an interesting failure mode I hadn't considered! I agree though, one of the reasons I liked the mini-split style horizontal exhaust outdoor units is that I could build a little roof over them to offer a bit of protection from stuff like freezing rain and snow.

    2. Aun Safe | | #15

      Same exact thing happens to my Trane XV18 during freezing rain.
      I bought a "weatherguard top" to see if it would fix the issue but haven't had any freezing rain since I installed it, so can't comment on whether or not it works.

  7. Jonny_H | | #9

    Thanks for the thoughts, everyone! I'm glad I'm not missing something major, and the proposed American Standard unit just seems like a poor fit for my application. I'm definitely considering a Fujitsu(or Carrier / Midea per Kyle) mini-ducted in the basement -- it's fully unfinished so the ductwork should be straightforward -- though ductless for the first floor still has some appeal just from installation simplicity / elegance.

    Also, I'm curious -- it seems like in general, heat pump efficiency decreases as size increases (ie, HSPF on Fujitsu ducted units is 9k -> 12.2, 12k -> 11.5, and 18k -> 11.3; on the ductless it's 9k -> 14, 12k -> 13.8, 15k -> 13.3; Carrier has a discontinuity in this relationship, 9k -> 12.2, 12k -> 11.5, 18k -> 11, but 24k -> 12.6. ) Sadly, even the Fujitsu technical data I used to be able to find online seems to have disappeared -- but I seem to recall seeing similar COP across the board at maximum output at 5F (from the capacity data table). What nothing has is tabulated data of efficiency across load conditions, so I wonder if a slightly "oversized" unit might actually end up being more efficient in some cases -- if it can modulate as low as a smaller system (meaning probably the same compressor), and it only operates at part load, with heat exchangers sized for larger capacity, it seems like it would potentially be more efficient than the HSPF numbers imply.

  8. Walter Ahlgrim | | #12

    Did you notice the America Standard Platinum 19? It looks to be a rebranded mini split.

    https://www.americanstandardair.com/products/heating-and-cooling/heat-pumps/platinum-19-low-profile-heat-pump/

    Walta

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