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LG Hydro Kit

NICK KEENAN | Posted in Green Products and Materials on

I’m curious if anyone has any thoughts or experience with the LG Hydro Kit. Or if you’re aware of other alternative units.

A fact sheet is here:
https://files.lghvac.com/resources//hydro%20kit_tp_01021_web.pdf

It’s an air-to-water hydronic unit that uses the same outdoor unit as a mini-split and basically replaces one of the heads. There are two versions, high temperature and low temperature. The high temperature version is rated at 86K BTU and can produce water up to 176F.  The low-temperature kit is rated at 107k BTU and goes up to 122F, but it also cools and can go down to  42F (95k BTU cooling capacity).  Either unit can also be used for domestic hot water with an indirect coil tank (they’re not rated for potable water). 

The LG catalog (https://www.lg.com/hr/klima-uredaji/2019-Multi-V-Catalogue_EU_0128_preview.pdf   ) says there’s also a 42K version of both high and low temperature but I can’t find any detail on them.  This would be more appropriately sized for my house. 

With a three-pipe outdoor unit you can have different heads heating and cooling at the same time, and if you do the heat from cooling is recovered. 

It sounds like this would be great if you wanted to mix and match mini-splits and radiant heat, or if you wanted to try radiant cooling. 

It almost sounds too good to be true. Which brings me to my question: I haven’t been able to find any evidence that it’s actually for sale, or that anyone is actually using it. To the extent I’ve found reviews they seem to be based solely on LG’s written materials and not on hands-on experience with the unit.

Any thoughts?

Thanks.

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Replies

  1. Expert Member
    Akos | | #1

    Being a commercial system, I can't see this being cheap, never mind adding in the "hydronic" premium.

    The high temp units only work with the 3 pipe systems, which is only the 5 ton unit. Heat recovery only really makes sens if you have something like a pool you need to heat in the summer time, otherwise the amount of "free heat" you need for hot water is pretty much noise.

    The low temp hydro kit does fall off in colder weather, so in my area, I would be limited to 100F water, which is still doable but hard to make it work with old cast iron rads and baseboards.

  2. Expert Member
    NICK KEENAN | | #2

    Thank Akos. For heat recovery it needs a separate heat recovery unit. Since the only scenario I can see for heat recover is domestic hot water, I think you're right and a stand alone heat pump water heater would accomplish much of the same end result but simpler and cheaper.

    As to the fall-off in colder weather, where are you getting the 100F number? And isn't that the knock on air-source heat pumps of all kinds, that when you need them the most they produce the least?

    Thanks.

  3. Expert Member
    Akos | | #3

    I went through their design manual a while back. Don't know where I found it. The low temp hydro kit delivers 120F for most outdoor temperatures, but drops off to 100F near -15C.

    I did find an online price for one overseas, works out to around $5k USD for a 2 ton + hydrokit. My guess you are looking at 15k installed. Definitely not budget heat.

    1. Expert Member
      NICK KEENAN | | #4

      Thanks Akos. I guess the question I would have is, if what you want is a hydronic system, how does this stack up against other options? It seems that the competitive system would be a condensing natural gas boiler. But if you're in a cooling climate -- as I am -- you'd also need a cooling system, so if you went with the hydro kit you could use the compressor that you already need anyway. So cost-wise, you're looking at the cost of adding the hydro kit to an existing cooling system, versus the cost of installing a boiler. The piping is going to be the same either way (I think).

      In that context $5K for the kit isn't that far out of line. Especially if there are long-term savings on energy costs.

      I appreciate your comments. Thanks.

      1. Expert Member
        Akos | | #5

        The question is do you need anything hydronics at all? With a well designed house, you are adding at least $25k to the cost with hydronics, so you have to make sure that is worth it.

        A while back I did an cost on Senden vs natural gas heat for a small space (open hydro air system running of a DHW tank). Not even remotely close. I can't see LG vs Modcon doing any better.

        I just don't think you can compete with the cost and performance of a ducted cold climate mini split.

        Energy costs wise, this would only make sense if you have hot climate with a large pool. Heat recovery there would probably give you a decent return but then you need the 5 ton unit, which I'm sure isn't cheap...

        1. Expert Member
          NICK KEENAN | | #6

          The problem I'm running into -- and I would appreciate any insights -- is that mini-splits just don't seem to scale. I'm working on a house that's going to be about 3700 SF, twelve rooms. It's two main floors, one room in an attic and a finished basement. Should I do twelve mini-split heads?

          Adding more rooms to a hydronic system is pretty simple.

          The third alternative is a conventional ducted system (which also has been ballparked around $25K). A hydronic system just takes up less space. This house will probably sell for around $675 per square foot ($2.5 million). So saving 40 square feet -- 10 SF per floor -- is $25K right there.

          1. Expert Member
            Akos | | #7

            The common way is with two air handlers, one on each floor. You can go fancy and have those zoned further. You can't really beat the cost and performance of a well set up system. The air handlers can be ducted split systems or standard gas/heat pump furnace.

            Trying to get radiant cooling working in any area with summer humidity is a waste of time/money. You still need an air handler for moisture removal, even the lowest SHR air handler will have significant sensible cooling capacity, the left over sensible BTUs are really not worth while trying to deal with radiant. You are just adding a lot of complexity.

            Nobody looks at the mechanicals for new houses, all people care about is what is visible, which are finishes.

            P.S. Radiant floor heat in the bathrooms and kitchen is a simple and noticeable addition, it is always worth it.

        2. SPDX | | #10

          Akos, any chance you could share that Sanden vs. natural gas for a small space analysis? That's the exact choice I'm wrestling with for retrofitting my own home right now.

  4. rhl_ | | #8

    this product was recommended to me as a redirect from a sales rep. I've been looking into air to water heat pumps for my house for the last few years, and recently i've gotten a bit more serious about it.

    the hydro kit is useful for more than just heat recovery, which I do think is a nice thing you get "for free" when you set this up, there is no more efficient way to make DHW than reusing existing heat.

    The point is you can use this to build an ATWHP. You can stick a hydro kit on an LG VRF outdoor unit, and then pipe that into your floor heating.

    I suppose you could also even use hydronic fan coils, although, you also can just pipe fan coils directly into this unit. I think this is an interesting premise.

    When you compare this to ATWHP if it really is $15k installed, that isn't so bad, perhaps not even compared to overall multi split systems?

  5. Expert Member
    NICK KEENAN | | #9

    I talked with an installer today. He said the Hydro Kit has limited availability right now, and that LG is requiring installers to get factory training before being allowed to sell them. He recommended I look at the SpacePak air-to-water units.

    He also said the HydroKit requires an outdoor unit from LG's commercial range, which would be more expensive.

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