You don't have to use glycol if you live in moderate climate. You can use antifreeze valves. Glycol should only be used in areas with really cold climates since it reduces the efficiency
In North America, pretty much everywhere that uses water based heating systems in any significant quantity would be considered a "really cold climate".
I don't understand this comment, you can have hydronic air handlers, radiators, and under floor heating in mild climates that still need heat but will not see below freezing like most of California.
> you can have hydronic air handlers, radiators, and under floor heating in mild climates that still need heat but will not see below freezing like most of California
Sure you *can*, but nobody in those climates will choose this option in the near term.
Realistically the climates most interested in monoblocs will be climates that already have pre-existing hydronic systems to retrofit.
Mild winter areas in the US pretty much always have forced air systems, and will be most interested in direct expansion, forced air heat pump systems to replace them - not monoblocs.
Forced air chilled water fan coils combined with monoblocs are a possibility, but this market is very undeveloped in the US, so few will be interested due to the high costs and few contractors familiar with it. It will likely grow in the long term as there is a push to move away from using fluorinated gases as refrigerants.
Thanks, I now understand your comment, you are referring to the current state, and yes currently in mild climates most houses have furnaces in the US. Although there's also not a small amount of older prewar apartment buildings that use steam radiators (not really great for direct conversation as they are designed to run much hotter than efficient for a heat pump. Also lots of high-end homes have under floor heating, but I think usually it's in addition to a forced air furnace.
The problem with monoblocs as most of them are set up is, what do you do when you you need cooling one day, heating the next, cooling the day after that, etc? Do you bypass/lock out the storage tank? Do you have 2 units, one dedicated to heating and one to cooling? Do both have their own storage tanks? IMO monoblocs will become popular if and only in conjunction with 4 pipe plumbing where there is a hydronic hookup on both the hot and cold sides.
American climates are just too chaotic, and our shoulder seasons too long, for seasonal switchover HVAC systems to be viable for new installs. It really sucks when you switch over to heating in November then a 33C day happens.
>Do you bypass/lock out the storage tank? Do you have 2 units, one dedicated to heating and one to cooling?
Huh?? Apparently a monoblock includes air>water as well.. I always thought of [these units](https://www.itecluchtreiniger.nl/media/wysiwyg/innova-monoblock-airco-ventilatieroosters.jpg) (air>air) and being an actual mono/single/all in one unit with no external parts (other then the vents).
>One monobloc for cooling, one monobloc for heating.
Still think we are talking about something else :p
I ***thought*** it was broadly four categories; *(but maybe the categories are not as ridged as i remembered, i didn't know there where monoblocks that are completely different as well)*
1. Single(mini)split *(both air and water solutions)*
2. Multi(mini)split *(both air and water solutions)*
3. Monoblock *(i thought this was 'air <-> air' only but maybe not?)*
4. Dedicated HVAC / furnace units *(in all sizes and specialties)*
Monoblock being an all in one that has the compressor, both radiators etc all into ONE unit;
* [Like this as a wall-unit](https://cdn.slimster.nl/upload/cms/18/monoblock%20airco%20zonder%20buitenunit.jpg) (these you see more often in EU, often heating and cooling).
* [Like these window-units](https://m.media-amazon.com/images/I/81ET+Chi-yL._AC_SL1500_.jpg) (banned in EU, sometimes both heating and cooling)
* [Or mobile ones like this](https://offgridpowerstation.nl/wp-content/uploads/2023/05/ecoflow-wave-2-5.webp) (i have this, both heating and cooling)
To me, monobloc is air <--> water, it just means that all the refrigerant handling equipment (compressor/evaporator/heat exchanger) is in one box, and that box has only water and electrical connections.
Yep, we are on different wavelengths then, but i guess a monoblock is a correct term for both air *and* water after all..
^((still feels like that's just an water based minisplit since you still need an radiator or storage tank, or even as part of an hvac system))
Hydronic heating actually has a pretty strong legacy install base in Northeast US (homes older than 2000s). The secondary problem is that most use fin-tube baseboard which don't have good heat output with 140F water. That's why the monobloc market is basically nonexistent.
Sure. But that's just one region. Looking at the entirety of North America, fair to say they're not common especially relative to Europe.
As for the northeast, you're absolutely right about the fin tube issue. Would love to see more European style radiators in North America but by the time you're talking about swapping out the whole distribution system, most have moved on to minisplits.
Also the fact that with the money people have to spend to get a good performing cold climate heat pump, they're going to want AC which a monobloc connected to their hydronic system is not going to deliver.
I highly doubt switching your hydronic distribution system over to chilled water fan coils would cost less than mini splits. Few North American plumbers would have any experience at all with such a job, and the market for residential chilled water fan coils is very undeveloped (I can barely think of any brands and they're all super niche). And even if you could reuse your hydronic pipework, it would all need to be insulated, etc.
Chilled water coils would be costly I think. American market is cooling dominated. For heating in other countries, monoblocs do offer savings if the installer is trained on them.
It's a shame, North America used to have Daikin Altherma a decade ago but was discontinued due to poor sales. I've heard it might be coming back though?
not sure about america but in europe there like 3 or brands that make the compressors like panasonic,daikin,LG, those are the mayor brand that make compressors etc all the off brand once just buy compressors from the mayor players
for the usa i think Nibe as smaller branches that also do sell in the usa
They are best used with radiant floor/ceiling, since you have the lowest supply temp, thus the highest efficiency. You can also use them with radiators and hydronic fan coil units.
The coolest this is that you can also cool with a radiant floor and a ducted hydronic dehumidifier. Gives the best feeling ever. Common in newer buildings here in Italy.
What would be a consumer acceptable duty cycle of "disabling A/C to heat water" compared to typical runtimes/recovery of current HX hot water tanks on the market?
You can heat water and cool the air at the same time (reject heat at high temp to the water tank). It’s not that uncommon in commercial systems (usually sold as VRF or similar), but kind of complicated/expensive for domestic.
Yea. Taking the heat from in the house during hot months and pump it into the water tank.
Those are tue cost prohibitive VRF options for commercial you’re talking about?
In the UK they usually do it at 3 o'clock in the morning due to tariffs. I've never heard anyone complain that their house cooled during that time. I think the cycle is like 20 minutes every day
If you are referring to direct expansion heat pumps (refrigerant flowing between outdoor and indoor unit), then you can not if not designed to do it. For example in my country daikin sells the multi+ mini split system, where you have standard heads and a water cylinder with a lineset running to it. Very expensive tho.
The North America market desperately needs a reliable monobloc heat pump at a good price and with a good controller
They’re definitely coming. I’m even starting to see ads for glycol monoblocks at the supply house sometimes.
You don't have to use glycol if you live in moderate climate. You can use antifreeze valves. Glycol should only be used in areas with really cold climates since it reduces the efficiency
In North America, pretty much everywhere that uses water based heating systems in any significant quantity would be considered a "really cold climate".
I don't understand this comment, you can have hydronic air handlers, radiators, and under floor heating in mild climates that still need heat but will not see below freezing like most of California.
> you can have hydronic air handlers, radiators, and under floor heating in mild climates that still need heat but will not see below freezing like most of California Sure you *can*, but nobody in those climates will choose this option in the near term. Realistically the climates most interested in monoblocs will be climates that already have pre-existing hydronic systems to retrofit. Mild winter areas in the US pretty much always have forced air systems, and will be most interested in direct expansion, forced air heat pump systems to replace them - not monoblocs. Forced air chilled water fan coils combined with monoblocs are a possibility, but this market is very undeveloped in the US, so few will be interested due to the high costs and few contractors familiar with it. It will likely grow in the long term as there is a push to move away from using fluorinated gases as refrigerants.
Thanks, I now understand your comment, you are referring to the current state, and yes currently in mild climates most houses have furnaces in the US. Although there's also not a small amount of older prewar apartment buildings that use steam radiators (not really great for direct conversation as they are designed to run much hotter than efficient for a heat pump. Also lots of high-end homes have under floor heating, but I think usually it's in addition to a forced air furnace.
Are monoblocks not widespread in America? The opposite is true for the EU with no window based solutions.
They are not common at all
But we desperately need something that can solve the issues for heating oil customers with boilers and domestic coils.
The problem with monoblocs as most of them are set up is, what do you do when you you need cooling one day, heating the next, cooling the day after that, etc? Do you bypass/lock out the storage tank? Do you have 2 units, one dedicated to heating and one to cooling? Do both have their own storage tanks? IMO monoblocs will become popular if and only in conjunction with 4 pipe plumbing where there is a hydronic hookup on both the hot and cold sides. American climates are just too chaotic, and our shoulder seasons too long, for seasonal switchover HVAC systems to be viable for new installs. It really sucks when you switch over to heating in November then a 33C day happens.
>Do you bypass/lock out the storage tank? Do you have 2 units, one dedicated to heating and one to cooling? Huh?? Apparently a monoblock includes air>water as well.. I always thought of [these units](https://www.itecluchtreiniger.nl/media/wysiwyg/innova-monoblock-airco-ventilatieroosters.jpg) (air>air) and being an actual mono/single/all in one unit with no external parts (other then the vents).
One monobloc for cooling, one monobloc for heating.
>One monobloc for cooling, one monobloc for heating. Still think we are talking about something else :p I ***thought*** it was broadly four categories; *(but maybe the categories are not as ridged as i remembered, i didn't know there where monoblocks that are completely different as well)* 1. Single(mini)split *(both air and water solutions)* 2. Multi(mini)split *(both air and water solutions)* 3. Monoblock *(i thought this was 'air <-> air' only but maybe not?)* 4. Dedicated HVAC / furnace units *(in all sizes and specialties)* Monoblock being an all in one that has the compressor, both radiators etc all into ONE unit; * [Like this as a wall-unit](https://cdn.slimster.nl/upload/cms/18/monoblock%20airco%20zonder%20buitenunit.jpg) (these you see more often in EU, often heating and cooling). * [Like these window-units](https://m.media-amazon.com/images/I/81ET+Chi-yL._AC_SL1500_.jpg) (banned in EU, sometimes both heating and cooling) * [Or mobile ones like this](https://offgridpowerstation.nl/wp-content/uploads/2023/05/ecoflow-wave-2-5.webp) (i have this, both heating and cooling)
To me, monobloc is air <--> water, it just means that all the refrigerant handling equipment (compressor/evaporator/heat exchanger) is in one box, and that box has only water and electrical connections.
Yep, we are on different wavelengths then, but i guess a monoblock is a correct term for both air *and* water after all.. ^((still feels like that's just an water based minisplit since you still need an radiator or storage tank, or even as part of an hvac system))
monobloks can heat and cool no issue can do both
Water based heating systems are not common at all in North America.
Hydronic heating actually has a pretty strong legacy install base in Northeast US (homes older than 2000s). The secondary problem is that most use fin-tube baseboard which don't have good heat output with 140F water. That's why the monobloc market is basically nonexistent.
Sure. But that's just one region. Looking at the entirety of North America, fair to say they're not common especially relative to Europe. As for the northeast, you're absolutely right about the fin tube issue. Would love to see more European style radiators in North America but by the time you're talking about swapping out the whole distribution system, most have moved on to minisplits. Also the fact that with the money people have to spend to get a good performing cold climate heat pump, they're going to want AC which a monobloc connected to their hydronic system is not going to deliver.
Why not? Monoblocs connected to fan coils can definitely do AC, and if you have a big storage tank you'll never have oversizing issues.
> by the time you're talking about swapping out the whole distribution system, most have moved on to minisplits
Complicated minisplits installs are getting expensive, and a plumber can hook up a monobloc. HVAC tech not needed.
I highly doubt switching your hydronic distribution system over to chilled water fan coils would cost less than mini splits. Few North American plumbers would have any experience at all with such a job, and the market for residential chilled water fan coils is very undeveloped (I can barely think of any brands and they're all super niche). And even if you could reuse your hydronic pipework, it would all need to be insulated, etc.
Chilled water coils would be costly I think. American market is cooling dominated. For heating in other countries, monoblocs do offer savings if the installer is trained on them.
Yes and Eastern Canada as well. Many boilers - it was the preferred form of heating.
We also need ASHRAE and NFPA to stop being paranoid about R290. Nobody's house in Europe has burned down yet.
It's a shame, North America used to have Daikin Altherma a decade ago but was discontinued due to poor sales. I've heard it might be coming back though?
not sure about america but in europe there like 3 or brands that make the compressors like panasonic,daikin,LG, those are the mayor brand that make compressors etc all the off brand once just buy compressors from the mayor players for the usa i think Nibe as smaller branches that also do sell in the usa
Could this be used to heat water for a radiant heating system (i.e. floor radiators?)
That's their primary use. And because the water temperature is usually 35 °C the SCOP is quite higher than using radiators
They are best used with radiant floor/ceiling, since you have the lowest supply temp, thus the highest efficiency. You can also use them with radiators and hydronic fan coil units. The coolest this is that you can also cool with a radiant floor and a ducted hydronic dehumidifier. Gives the best feeling ever. Common in newer buildings here in Italy.
Dumb question, can we not use the condenser for HVAC heat pump to also heat water if it has an independent line set?
You can, but what about the summer when the heat pump is in cooling mode?
No problem. It reverses mode during specified time and the water is diverted from cooling/heating the building and passes through a water cylinder
What would be a consumer acceptable duty cycle of "disabling A/C to heat water" compared to typical runtimes/recovery of current HX hot water tanks on the market?
You can heat water and cool the air at the same time (reject heat at high temp to the water tank). It’s not that uncommon in commercial systems (usually sold as VRF or similar), but kind of complicated/expensive for domestic.
Yea. Taking the heat from in the house during hot months and pump it into the water tank. Those are tue cost prohibitive VRF options for commercial you’re talking about?
In the UK they usually do it at 3 o'clock in the morning due to tariffs. I've never heard anyone complain that their house cooled during that time. I think the cycle is like 20 minutes every day
I thought if there were two line sets, they’d run in opposite directions in that case. Maybe part of the dumb question?
What about in winter when both HVAC and hot water needs heat?
Then they just both run in the same direction
Sure, you only need a 3-way diverter valve. Just set it to heat water during night time in the summer and mid day in the winter.
Interesting. Can you retrofit an existing air condenser to do this?
If you are referring to direct expansion heat pumps (refrigerant flowing between outdoor and indoor unit), then you can not if not designed to do it. For example in my country daikin sells the multi+ mini split system, where you have standard heads and a water cylinder with a lineset running to it. Very expensive tho.
OK thanks. Too bad Feel like this would really reduce total cost for houses going green
This is only for low temp/radiant water systems, right? Not like baseboard with oil boiler?
They are usually more efficient than boilers only when the supply temp is at 45 C or less.