We're talking about Hitachi heat pumps, but the company behind them is majority-owned by Johnson Controls, a giant in the world of building controls. One of their control installations at the Pentagon is said to have saved much of the Pentagon following the attacks of 11.09.2001. In October 2015, Johnson Controls and Hitachi joined forces in a joint venture, with Johnson Controls holding 60% and Hitachi Air Conditioning solutions 40%.
The brand does not specialize in heat pumps, but in all types of systems for thermal comfort, whether in the residential or commercial sector. Hitachi offers its Yutaki S range of heat pumps, newly gratified with a 2.0, as well as a variety of wall-mounted air conditioners, ducted units, cassettes for hairdressing salons or gyms, etc. (small commercial sector). In the commercial sector, they offer more industrial units, chillers, DRVs, etc.
NB : Our partners RGE, GSP or RESCERT (France, Switzerland, Belgium) will send you a free estimate for a Hitachi Yutaki or other model of air-water heat pump according to your request => via this quick form
For the purpose of this review, we're going to focus on the Yutaki Combi S 2.0, that product you can see in the picture below, whiter than white, on the right side of this oh-so-perfect laundry room.
In addition to this fridge-style block, there's a group to put outside, a bit ugly as usual for all brands, which is why it doesn't appear too often on the brand's docs or marketing material.
Well, in real life, it's like this inside (left) and there's the outdoor unit (right: the photo is for small power ratings, for larger ratings the unit must be doubled: equivalent to 2 superimposed in height).
The Yutaki Combi S 2.0 is a split air-to-water heat pump with the domestic hot water cylinder integrated in the indoor module.
This means that the outdoor unit captures heat from the outside air via the refrigerant circuit, compressor and evaporator it houses.
The indoor module redistributes the heat to the mains water via a condenser.
Since the product is made up of two parts, it's called a bi-bloc. Refrigerant must circulate between the two parts, thanks to the refrigerant pipes that link them, but which also constitute a point of fragility in the system, the seat of possible leaks over the medium to long term, if not installed with care.
The product has just undergone a 2.0 facelift, demonstrating the dynamism of the residential heat pump market against a backdrop of substantial government subsidies for some time now.
Hitachi Yutaki Combi S 2.0 aesthetics
The Yutaki S's appearance was beginning to show its age. The light gray in which it left the factory has been replaced with the 2.0 by a very modern pure white, which has been slightly amplified by photo retouching. The indoor module will fit perfectly into a machine room, a laundry room as shown in the photo, a garage, or even a busy room. Its fridge-like appearance will quickly make it go unnoticed.
As for the outdoor unit, you'll need to place it in a spot that's not too conspicuous in the garden, or on the facade, behind a wall perhaps. The photo above speaks for itself.
The new Yutaki S Combi 2.0 controller has won the European Product Design Award. It sure is stylish!
The performance of the Yutaki S Combi 2.0 R410A or R32
For small capacities up to 8kW, Hitachi offers the R32 outdoor unit, then from 11kW upwards it always works with R410A, a fluid that will no longer be possible to use in new installations containing less than 3kg by January 1, 2025, due to its GWP (global warming potential...aie the ozone layer) three times higher than its replacement.
It is available in 6 models from 4.3kw to 16kW (power at 7°C outside air, 35°C water outlet from the heat pump).
Let's start with the models connected to the outdoor unit that runs on R32
The new gas of the future, until the next gas of the future. As Hitachi's motto says: "Inspire The Next".
| Hitachi Yutaki S Combi 2.0 R32 | 4.3kW model (A7/W35) | 6kW model (A7/W35) | 8kW model (A7/W35) |
| Power (A-7/W35) | 5.3kW | 6.2kW | 7.5kW |
| Power (A-7/W45) | 5kW | 5.8kW | 6.67kW |
| Power (A-7/W55) | 4.2kW | 5kW | 5.5kW |
| COP A7/W35 | 5.25 | 4.8 | 4.6 |
The line to take into account depends on your case. If you are in low temperature, with underfloor heating, you can read the first line to have an idea of the power developed in winter if it is -7 and you provide 35°C water to your underfloor heating. Moreover, the COP of the last line corresponds to what you will obtain in reality.
However, if you need to supply your network with hotter water because your emitters are older or so designed, then you need to look at the other two lines. With older radiators, the last line is relevant because you'll need to bring them up to 55°C. As you can see, the power delivered is lower. Moreover, the COP is not the right one. You'll need to recalculate it for this water temperature of 55°C, because as it stands, it's only valid for 35°C. The COP will be lower.
The DHW cylinder has a capacity of almost 300 liters, which is ideal for a family of 4 to 7 people. You'll need 2 hours to raise the volume of water from 10°C to 55°C, assuming an average outside temperature of 20°C, so much longer in winter.
This heat pump can also be used for cooling in summer, as it is reversible. The Yutaki S Combi 2.0, the largest R32 model, delivers up to 7 kW of cooling capacity. Enough to provide cooling for a 100m2 BBC home, or for an older 60m2 house, for example. The latter is a bit "just", but you have to realize that cooling is a luxury, so you can also accept not cooling perfectly to limit consumption and make a few savings.
Let's continue with the models connected to outdoor units running on R410A
| Hitachi Yutaki S Combi 2.0 R410A | 11kW model (A7/W35) | 14kW model (A7/W35) | 16kW model (A7/W35) |
| Power (A-7/W35) | 10.6kW | 12kW | 13kW |
| Power (A-7/W45) | 10kW | 11.6kW | 12.5kW |
| Power (A-7/W55) | 9.7kW | 11.2kW | 12kW |
| COP A7/W35 | 5 | 4.71 | 4.57 |
This R410A model, in its largest version, can deliver impressive power, enough to heat a city of around 150/200m2 depending on the region and type of emitter.
The COP values shown are only valid for underfloor heating. If you have old radiators, ask your installer for the real value.
The domestic hot water (DHW) cylinder, with a capacity of 288 liters, will be brought up to temperature in 1 hour 05 minutes if it's 20°C outside. If not, it will take longer.
For cooling, you can go up to 10.5kW, with an EER of 3.3 (EER = equivalent to COP but in cooling)
Acoustic or noise for this Yutaki S
The interior module of the Yutaki Combi S 2.0 is rated at 37dBA sound power, which is low, practically inaudible, depending on the existing noise in the room, the consistency of the walls and the acoustic insulation of the walls. For the highest power ratings, this value peaks at 39dBA, which remains in the same order.
Sound pressure at 1m from the outdoor unit ranges from 46dBA for the lowest power rating to 50dBA for the highest. The latter may require you to install an acoustic enclosure for the heat pump, depending on your area of residence, so that the noise generated does not exceed 5dBA in relation to ambient noise during the day, and 3dBA in relation to ambient noise at night (more difficult in quiet or less quiet areas at night). These limit values are taken from the French Public Health Code, which considers the emergence of noise from your machine in comparison with the noise of the environment in which you are located, distinguishing between day and night.
The documentation does not necessarily specify how these dBA values are measured. Ask your installer for more detailed information on acoustics. They may vary, for example, if you install the outdoor unit along a wall, or in the middle of a field, or in a corner.
Reverberation amplifies noise. You have to think about all this a little, so that the result doesn't disturb the whole Republic, and land you in court. You've got other things to do, like measuring your energy savings with the magnificently-designed control system we'll talk about later.
Some notable technical features for this machine
All the connections, whether water or refrigerant, are grouped together on the top of the machine in a very practical way. This will make your installer's life easier than yours. It's an ideal configuration for efficient maintenance.
The domestic hot water tank is compact, since it fits into the inner module with a cross-section of approx. 600 x 600mm. Its special features include the material it's made of, DUPLEX steel. Stainless steel highly corrosion resistantwhose development is attributed to the Scandinavian offshore industry.
These stainless steel grades were first developed to solve problems of high corrosion in the North Sea oil fields. The alloy contains nickel, molybdenum and chromium, as well as nitrogen, which enhances resistance to pitting corrosion. This feature ensures that Hitachi systems have a long service life.
Finally, with the Yutaki S 2.0 Combi or not, Hitachi offers an optional 2-zone kit, enabling you to manage two zones in your home that require different water temperatures. For example, if you have an underfloor heating system in one part of your home, and a radiator system in the other.
What is the price of the Yutaki Combi S 2.0
Depending on power, you'll find these heat pumps, equipment only, for between €5,000 and €10,000 for the biggest power. This price does not include installation, which will cost between €5 and €10k more, depending on your region and installer.
If you're looking for the Yutaki S Combi 2.0, your best option is probably to go through an installer who enjoys professional discounts with major suppliers, and will enable you to get the equipment at the best price.
These are the professional prices in the official Hitachi 2021 public catalog for the Yutaki S and Combi S: your installer will benefit from discounts on them, depending on his annual installation volume, perhaps between 10% and 30%. As a private customer, you won't be able to order direct.
for Combi S
And it's not just the purchase price that counts. In France, for this heat pump, you can receive consequent aids. In fact, if you'd like to find out more, you can read the article on heat pump subsidies in France. You'll also need to plan for maintenance, costing a few hundred euros more per year, if you want to benefit from the warranties. Finally, since the air-to-water heat pump is still an electric heater, you'll need to factor in the cost of electricity and calculate how much it will cost you.
To calculate the electricity consumption of a heat pump, if you were previously on electric (basic electric radiators), then you can get an estimate by dividing your bill by the machine's SCOP (average COP). Example: you used to consume €3,000 a year in electricity (€250 a month), now you'll have a bill of €1,000 a year, or €83 a month.
You can also take the power consumption from the data sheet, at the average temperature and for the water temperature that concerns you (35°C underfloor heating, 55°C old school radiators), then multiply it by the number of hours the heat pump will run in the year.
We never really know this figure, but there are known averages, and in France in particular it's around 1800 to 2200 hours per year, depending on the region, or even a little more in colder regions. For example, for the Yutaki S Combi 2.0 8kW with R32, this would give you on underfloor heating: 1.74kW x 2000h = 3480kWh per year. For kWh at around 0.16 cts, this would give you a bill of around €550 a year, or less than €50 a month (rough estimate).
Regulation, a pride of the Yutaki S Combi 2.0
Let's get down to the point of Hitachi's pride and joy, as the brand won a European Product Design Award in 2020 for the controller. You can see here this mention on the official website.
Overall, this product responds to a demand for simplicity in navigation to temperature setting by the heat pump end-user. The usual products prioritize other aspects, whereas Hitachi delivers a simplified, colorful user experience that's more comfortable than average, thanks to a worked-out key angle. Even a very young child will be able to adjust the temperature with ease, just remember to place it at a sufficient height :).
This controller connects to the Hi Kumo remote maintenance platform, which allows a higher reactivity in case of failure or defect. Your installer can therefore make his diagnosis remotely, if you grant him access to your PAC, via the network.
How much space does this heat pump take up?
Here are the technical specifications of the Yutaki Combi S 2.0
This heat pump has the advantage of a compact internal module that fits neatly into a kitchen, and contains the domestic hot water cylinder, eliminating the need for a separate cylinder and saving space in the home.
As for the outdoor unit, for the smaller R32 models the height of 630mm will make it easy to conceal, which is less the case for the larger outdoor units with almost 1.40m high.
Overall,
Hitachi updates its popular Yutaki S range, focusing on improved ergonomics and design, through a more modern interior module and a controller that has won awards for its simple design.
This heat pump doesn't require a lot of space, and offers fairly high SCOPs (average cop for average climate) at over 4 for underfloor heating, which has yet to be measured in practice.
Noise from the outdoor unit must be taken into account, not only to determine the ideal position for the machine on your property, but also to protect you from legitimate claims or complaints under the French Public Health Code. Ask your installer, and if he's not sure, call in an acoustic expert. It'll cost you a few hundred euros, but you won't be sued if he advises you correctly.
Also worth reading about:
Review of another Japanese pac: Panasonic Aquarea.
Opinions on the daikin Altherma 3 H HT
TOP 20 Best air-to-water heat pumps
About the author
Juliena mechanical engineering graduate and specialist in climate engineering since 2009, has become a writer specializing in renewable energies, with expertise in heat pumps and photovoltaic solar panels for individual housing.
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