We have a conflict and won’t be able to attend so please take good notes and post them...and post some photos and perspectives on the LG too when you get back from that visit...

I did get some good info from Dennis after telling him we also had a conflict. This product is a combo boiler and air source heat pump. Unlike the NextGen, it doesn’t have all the sundry HR components (e.g., pump, expansion tank, etc.) to be fully plug and play for HR floor heating. I will need to study this info in detail and likely view the webinar too at a later time to learn more about this product. Been crazy busy on the west coast and currently heading out to LV for a conference...

The downside to the NorAire system is it only works with single stage heat pumps. They claim to be working on some two stage configurations; but I can't imagine they will be able to interact with all the proprietary communicating heat pumps out there.....

Thanks for pointing this out. I had seen this product but hadn't realized it was capable of working with a Hydro Kit. At first glance, it appeared to only work with 3-phase Multi V systems: https://lghvac.com/commercial/product-type/?productTypeId=a2x44000003XQzL&iscommercial=true But further investigation led me to this document which does indicate that it is a single phase product: https://files.lghvac.com/resources//VRF_EM_BT_001_US_013K31_LGEngineeringManual_MultiVHydroKit.pdf.pdf The heating/cooling capacity of this unit seems huge -- probably total overkill for a modern ICF 2000-2500 foot home right? This LG looks like it might be the best all around option. If there was an R32 system of the same type available now in North America, that would be even better, but it seems like that is probably a few years away.

Well, you really need to first do a heat gain/loss analysis (ACCA ManualJ8 or ASHRAE) before you can properly size the AC/heating systems. We only use a 4 kW (13,650 Btu/h) electric boiler to hydronic radiant floor heat our southern Oregon 2400 sf ICF home. On sunny days (which occur on the coldest days), we get about 45% of our daily heating needs from our passive solar heating design. We don't need any AC (only a whole house fan that only runs a couple of hours during the night) because of our Summer diurnal, low humidty climate and our passive solar cooling design.

The smaller 14kw / 48 KBTU output version of the low temp hydro kit wouldn't be overkill for for a 2000-2500' ICF house. In an even higher performance very low heating load house one could use just one for both heat and hot water, utilizing the "reverse indirect" as the thermal buffer for the heating system. Click on Line Up and you'll see they make two sizes for the low-temp Hydro Kit, two sizes for the higher temp Hydro Kit.

https://www.lg.com/global/business/air-solution/vrf/hot-water-solution-hydro-kit

(I don't know what the model numbers are for those kits are, and the LG websites are a real PITA for surfing for even simple model numbers, let alone technical documentation.)

Just one 14kw version of the Hydro Kit could easily serve both heat and hot water for sailawayrb's house with the heating system works on a 4kw electric boiler if the heating system controls are set up to never draw heat at a rate higher than 4kw from the reverse-indirect. The Sanden CO2 refrigerant water heater could heat that place, but not both heat + hot water under peak conditions.

We use two 24 kW (82,000 Btu/h each) tankless water heaters, located on opposite sides of the house, for our DHW. This approach provides hot water more quickly to where it desired, provides a high flow rate (nice for filling my jetted tub) and provides some redundancy (we live in a remote area) should one unit fail. Since each tankless water heater pulls 100A and we only have 200A service, only one water heater is allowed to operate at any one time using a load shed system (current sensors and solid state relays). Since we have both solar PV and hydro power, this is a good solution for our place.

Just like a 10 ton air conditioner, a big electric tankless can be fairly abusive to the local grid's power quality, even when operating within the capacity of the wires & transformers. It's one of those things that can works out OK if only a few people on the local grid are using them, but can potentially degrade power quality to a serious level if everyone in the 'hood was going that route. As a generic solution I personally tend to avoid recommending them where there are other alternatives available, no matter how green the power source.

The grid infrastructure needed for managing heavy intermittent grid loads are often paid for on commercial & industrial ratepayers as a "demand charge", a line item per kw (not kwh) of power use during the heaviest-use quarter hour or half hour during the billing period, and it's often the biggest line item of the bill. In some locations the utilities are lobbying to apply demand charges to residential customers with PV (which sounds like it would include the Borst family) as a means of recovering the costs of grid infrastructure & service. So far there has been succesfully lobbied against by the residential solar industry, but not everywhere, it seems:

https://www.utilitydive.com/news/will-the-countrys-first-mandatory-residential-demand-charge-slow-the-massa/515189/

https://www.euci.com/event_post/0518-residential-demand-charges/

If/when that sort of thing ever gets implemented in your neighborhood filling the Jacuzzi with a 24kw tankless might get be pretty expensive relative to thermal storage a tank that recovers at a much lower draw.

If you add to that a dumb Level II EV charger it can get even more out of hand.

Eventually smarter EV chargers could improve local grid power quality even in the presence of big tankless water heaters or similar loads, but that won't be next year.

Our vegetable oil Listeroid generator, hydro and solar alternative power isn't tied to the utility grid power. We typically fly on our own alternative power, but we did bring in 600A of grid power to the property (200A for house, 200A for guest quarters and 200A for shop). We had to pay the power company a lot of money for our large personal transformer. Each 200A service can be isolated and transferred to/from alternative/grid power. We typically only have our shop feeding from the grid. We don't use anything less than 20A/12G wire for the electrical circuits and we never see any flickering lights.

Since it is mostly only the two of us these days, the tankless heaters are way more energy efficient than a tank heater unless you are willing to deal with the complexity of a heat pump tank. Tanks also have a higher risk of causing disease, especially for older folks and especially when you use stream and well water like we do. So I think we are about as green as we can be, all things considered.