Seeking Opinions on Daikin Fit Heat Pump
Nola_Sweats
| Posted in General Questions on
Anyone have a strong opinion on the Daikin Fit heat pump? It has a side-discharge compressor system that looks like a mini-split, but it functions as a split system with an indoor air handler. 2018 SEER, variable speed. My alternative is a Lennox 25 SEER heat pump, more expensive and more efficient, but with a traditional large compressor that would squat in my back yard. Both are very quiet systems, so it’s size vs. efficiency. The efficiency of the Lennox is not enough to offset the higher cost even over 15 years, but the Lennox seems to be a better-known system.
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Getting the capacity size correct is critical for comfort, even with modulating systems. The modulation ranges aren't infinite. What are your heating & cooling loads?
Is this a retrofit onto an existing duct system, or is it an all-new installation?
Carrier/Bryant (== Midea / Toshiba) 40MBDQ slim duct cassette systems might be another lower-cost option with high SEER/HSPF. Like Fujitsu's xxRLFCD ducted mini-splits (and UN-like most other vendors' low & mid-static ducted mini-splits) the pancake style air handler can be mounted in a vertical orientation. The smallest in the series is a 3/4 tonner, but they come as large as 5 tons.
A typical 3-tonner runs north of 20 SEER, with an HSPF north of 11, eg:
https://ashp.neep.org/#!/product/36680
Thanks, Dana. These are existing ducts, all in conditioned space, so they'll just be attaching the new air handler to the existing plenum.
I don't know the heating/cooling loads yet: for the free estimates, the A/C contractors are ballparking the size based on rules of thumb, but they will do a Manual J to determine a final size. They know that I refuse to be oversized, because I've drunk the GBA Kool-Aid. Part of the reason I'm replacing the 2.5-ton unit I have now is that the existing 15-year-old unit has become oversized as I've upgraded the house's insulation and energy usage.
For whatever reason, Carrier and Bryant aren't common brands in this area. They exist, but with relatively few dealers. If I want variable speed, it's mainly American Standard/Trane, Daikin, or Lennox. I've mostly ruled out AS/Trane because their smallest side-discharge unit is two tons, and it only modulates down to 50%. I'm concerned that a half-ton will be oversized in the spring and fall, so I'm leaning to the Daikin that reportedly dials down to 25% and is also available in a 1.5-ton. Lennox and the larger Trane/AS units go to 30 or 35%, but the full-size compressor is a negative in a small courtyard.
>"I don't know the heating/cooling loads yet: for the free estimates, the A/C contractors are ballparking the size based on rules of thumb, but they will do a Manual J to determine a final size."
Unless I've worked with them before and know the level of diligence & competence, I would NEVER take an HVAC contractor's Manual-J as something meaningful. It's a sad fact that the industry at large is egregiously bad at getting it right, even when going through the motions of performing a Manual-J. A qualified third party such as a certified professional engineer whose reputation is made/lost on the accuracy of the numbers is really the right person to run those numbers, not a contractor whose real bread & butter is selling/installing/maintaining equipment, where the incentives are stacked in the wrong direction.
If it's replacing an existing functioning system it's possible to use the existing equipment to measure the 1% and 99% design loads. The AC load can be measured by use of data loggers to measure the duty cycle on afternoons that cross or near the 1% outside design temp. This method automatically includes all parasitic duct losses, etc, since those can't be factored out. For a more detailed explanation of how to do that see:
https://www.greenbuildingadvisor.com/article/how-to-tell-if-your-air-conditioner-is-oversized
To estimate your local design temps see:
https://higherlogicdownload.s3.amazonaws.com/ACCA/c6b38bda-2e04-4f93-bd51-7a80525ad936/UploadedImages/Outdoor-Design-Conditions-1.pdf
Even though the older equipment will likely have lost some capacity due to age, and your 1% design temp & indoor design temps probably don't match the EER and SEER test numbers, using the nameplate BTU ratings x duty cycle will usually be more accurate than a Manual-J, even more accurate if using data from multiple days. Resist the urge to upsize by more than a half-ton from that point, since the actual cooling BTU from 15 year old equipment is more likely to be somewhat less than the nameplate rating.
With heat pumps it's a bit tricker to do the same duty cycle thing at the 99% outside design temp- it's often important to have the manufacturer's extended temperature capacity tables, and data taken after sunrise on sunny days can be skewed quite a bit by solar gains. With fossil burners it's reasonably accurate in US climate zones 4 & higher to run fuel-use against heating degree-day weather data for WINTERTIME-only periods, as explained here:
https://www.greenbuildingadvisor.com/article/out-with-the-old-in-with-the-new
Sizing the equipment capacity by no more than 1.4x from the fuel-use based calculation will cover the vast majority of deep cold snaps, and deliver very favorable seasonal efficiency & comfort during the heating season.
Duct sizing matters when replacing 13 SEER (or lower) equipment with newer higher efficiency goods, since the older stuff was designed to accommodate higher static pressures. But if downsizing from a 2.5 ton with a reasonably designed duct system to 1-1.5 tons it'll usually be OK (but competent designers would run the numbers regardless.)
We just installed a Daikin Fit 2 ton split system a week ago after our 20 year old Carrier R-22, 2.5 ton heat pump developed a leak in the air handler coil in mid February. Heat strips took care of the cold spell then, so it was good to have them and not have to buy electric space heaters, even though the strips were very rarely used after insulation upgrades, new windows, etc. over the years. The old system was single speed and sized such that aux. heat was only needed around 0F and below, which happens every 2-4 years for a few days in winter at our location.
I also looked at the 2 ton Trane/AS side discharge with TAM9A0A24V21 air handler and got a quote, but the price was about $2k more expensive than the Fit system, and didn't include MERV 16 air filter like Daikin (reused old Aprilaire MERV 10). Also, the Daikin price included a new surge protected outside shut off, the Trane quote did not.
I had another knowledgeable Daikin dealer (not Comfort Pro) give me a quote on a SkyAir 2.5 ton with compatible VS air handler, but that system is really designed for either commercial, or maybe a more northern climate residential, due to its huge top end capacity. Not ideal for tight, regular sized homes, due to minimum capacity being too high.
I went with the same company who installed our Carrier unit 20 years ago. I was happy with the old unit and their professional install, so choosing them was easy. As a comfort pro dealer, they offered me access to Daikin Fit rebates, which just ended March 31st with April 15th install deadline. Such rebates are typically offered January-March and September-November.
So far so good. Super quiet outdoor unit and a small footprint. Both were high priorities for us. I can't give a thorough review yet, as its only run the last few days for minimal heating needs and AC season will start here in May. I will post a more thorough review here in the comments section after using it and observing its behavior.
Not sure where you're located, but the Dakin Fit is rated to operate down to -20F, assuming the line set is 30 feet or less in length. Obviously the heating capacity is very reduced below 0F-5F, but it's still nice to have some heat pump heat when it gets that cold.
Many manufacturers will not publish their minimum (heat pump compressor) operating temperature. Full disclosure it always the best.
We had a daikin fit 4 ton unit installed in 2020 and there advertised literature said it would operate to -29C. In winter of 2021 when cold weather came it shuts down at -18C so we discussed with Daikin reps and were told the new specs were -23C as it would not opperate down to -29C. We of course were dissappointed as we have electric aux heat as backup. The installers made some changes too installation the main one was shortening the line to less then 30ft. Hoping this would allow colder operation.
So how do we trust and now if specifications are right until cold weather arrives.
So winter 2022 -18C and heat pump stops working again.
What a a costumer do in this case.
Help
Ron in Ontario Canada
I did end up getting the Daikin Fit, and I'm very happy with it. It's what they said it would be -- small, quiet, very efficient. Small is key for me, because the compressor hangs on a wall and replaces a traditional compressor that took up a good chunk of my small courtyard. I really like the variable speed that keeps the house a constant temperature, rather than temps fluctuating as the unit cycles.
No complaints so far, and I've had it for about 9 months. I've been comfy through a sauna of a New Orleans summer and in winter temps down to freezing. It's too bad that Ron's isn't working as advertised below -18. At 32 degrees outside, the Daikin Fit makes my house much more comfortable than the circa 2006 heat pump that it replaced.
The structure of the menus on Daikin's proprietary thermostat are clunky, but that's just a software issue. The Daikin thermostat communicates better then the Nest that it replaced. The Nest was always having communication issues, and was always trying to get me to sign up for various Google products.