AquaThermica Hot Water Tank

[Mk555blue]

Hi all,

I’m in the process of renovating a property which currently uses an old gravity fed hot water cylinder with immersion heater. The heating is old electric storage heaters. The village has no mains gas, so after much research I have decided on using an air to air heat pump for the heating. For the hot water i am looking into an air source hot water tank, and i came across the AquaThermica by Tesy. Does anyone have any input as to the quality and efficiency of this tank? Or if there is a better make on the market? Im particularly interested in how loud it is as if its vey loud it may need moving from the airing cupboard in my current plan.

Thanks

[JohnMo]

That cylinder is carbon steel and epoxy paint lined.  So needs an anode to protect from pin hole leaks - You need to replace this every so often. Dimplex do the same thing but with stainless steel cylinder, so do Mixergy.

 

Makes expensive hot water, if you are adding a heat pump anyway.  Just get and unvented cylinder for a heat pump, for about the 1/3 the cost. The heat pump will heat the cylinder via a diverter valve.  Keep the additional cost of the Tesy or other similar in you pocket.

 

 

[Beelbeebub]

1 hour ago, JohnMo said:

That cylinder is carbon steel and epoxy paint lined.  So needs an anode to protect from pin hole leaks - You need to replace this every so often. Dimplex do the same thing but with stainless steel cylinder, so do Mixergy.

 

Makes expensive hot water, if you are adding a heat pump anyway.  Just get and unvented cylinder for a heat pump, for about the 1/3 the cost. The heat pump will heat the cylinder via a diverter valve.  Keep the additional cost of the Tesy or other similar in you pocket.

 

 

They mentioned air to air which limits the hot water options.

 

I believe Daikin have an unvented cylinder that connects to a multisplit outdoor unit in the same way the heating units do.

 

There are some Chinese cylinders on eBay that do the same but I have no idea as to quality.

 

 

[JohnMo]

1 hour ago, Beelbeebub said:

They mentioned air to air

Good point 

 

Then this could be an option 

 

https://www.ebay.co.uk/itm/185631610657?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=yawjptzcrle&sssrc=4429486&ssuid=8KgwDlAbTJS&var=&widget_ver=artemis&media=COPY

[Mk555blue]

13 hours ago, JohnMo said:

That cylinder is carbon steel and epoxy paint lined.  So needs an anode to protect from pin hole leaks - You need to replace this every so often. Dimplex do the same thing but with stainless steel cylinder, so do Mixergy.

 

Makes expensive hot water, if you are adding a heat pump anyway.  Just get and unvented cylinder for a heat pump, for about the 1/3 the cost. The heat pump will heat the cylinder via a diverter valve.  Keep the additional cost of the Tesy or other similar in you pocket.

 

 

Thanks for your reply. You say it makes expensive hot water-are heat pump hot water tanks expensive to run? My choice is between this or immersion really. I’m avoiding installing oil or lpg, and for ashp I’d rather air to air over air to water. 

[JohnMo]

38 minutes ago, Mk555blue said:

You say it makes expensive hot water

When you take into consideration the cost difference between an unvented direct (immersion cylinder) and the heat pump on cylinder version to buy. So like for like materials. 210L

 

UVC direct heated £500

Dimplex Edel £2400.

 

Advantage is CoP of 3 compared to CoP of 1 for immersion. Daily cost is 1/3 for the heat pump cylinder.

But you have a few years to make up the cost difference overall. Around 5 years to break even point cost wise based on buying and heating costs.

 

Plus you have to route ducts in and out of house. An extra cost adder, 2x 160mm holes through wall plus duct. If using house warm air from house, this is likely to need to be replenished via the A2A for the heat pump cylinder.

 

Other consideration 

Time to reheat is very long for HP cylinder, so check that out.

 

As you mentioned noise?

 

Service and parts, you are going to a glazed over look, from the plumber for HP cylinder.

 

[Beelbeebub]

Stand alone heat pump cylinders (an unvented cylinder with a small self contained heatpump sat on top) will always cost less to run than an immersion.

 

However they are more to buy. A. Typical immersion heater cylinder is under £1k.  A heatpump cylinder is at least double if not triple that.

[Beelbeebub]

I don't see why someone doesn't make a drop in replacement for an immersion - just a coil of copper pipe - that connects to a standard a2a heatpump. Only difficult bit might be the electronics to fool the HP.

[Gone West]

4 hours ago, Beelbeebub said:

just a coil of copper pipe

Would you be able to rig up a Willis Solasyphon for something like that?

[Beelbeebub]

4 minutes ago, Gone West said:

Would you be able to rig up a Willis Solasyphon for something like that?

Maybe.

 

Or even just use a plate heat exchanger.

 

PHX for refrigerant to water exist. They are in every single air to water heatpump

 

So all you need is one of those, possibly a circulator pump and some control electronics to get the HP to think it's just a standard fancoil.

[Beelbeebub]

What would be really interesting is if a PHX can provide sufficient thermosypon effect at the temperatures and power levels typical to avoid the need for a circulator pump.

[PhilT]

8 hours ago, Mk555blue said:

for ashp I’d rather air to air over air to water. 

What did you have in mind, individual split units for each room, or a central unit with a fan in each room? Both can also do air con. Do you know neither of these qualify for any grant? The BUS £7500 is only available for "hydronic" systems. Have you done any costings? By the time you have added up the capital and installation cost of an air to air system I wouldn't be surprised if it costs more than a full hydronic system net of grant.

Edited December 28, 2024 by PhilT

[Beelbeebub]

1 hour ago, PhilT said:

What did you have in mind, individual split units for each room, or a central unit with a fan in each room? Both can also do air con. Do you know neither of these qualify for any grant? The BUS £7500 is only available for "hydronic" systems. Have you done any costings? By the time you have added up the capital and installation cost of an air to air system I wouldn't be surprised if it costs more than a full hydronic system net of grant.

Dunno, I've had quotes of 5k all in for a multi split (4.rooms.iirc).

 

If you just stick a direct invented (less than 1k) on that's 6, maybe 7k with no faffing.

 

Installing a wet system is a lot of paperwork, plus you need to pipe rads to each room. Which might (depends on layout and routing) be very disruptive and costly.

 

It's not unusual to hear people paying north of 10k after the grant for an install.

Edited December 28, 2024 by Beelbeebub

[Mk555blue]

On 28/12/2024 at 17:43, Beelbeebub said:

Dunno, I've had quotes of 5k all in for a multi split (4.rooms.iirc).

 

If you just stick a direct invented (less than 1k) on that's 6, maybe 7k with no faffing.

 

Installing a wet system is a lot of paperwork, plus you need to pipe rads to each room. Which might (depends on layout and routing) be very disruptive and costly.

 

It's not unusual to hear people paying north of 10k after the grant for an install.

cheers guys, I’m evaluating all my options and what would make the most sense. I intend to get quotes for air to water as well as air to air and then make a decision. I think if I were to go air to air I’d just have a normal vented direct hot water cylinder. Cheap to install but expensive to run, however with electric showers I shouldn’t need a particularly big cylinder. I have looked at cylinders with inbuilt ashp, but they aren’t cheap. Does my approach make sense? It’s all a bit new to me. My original intention was just to install oil, but I don’t think that would be logical now. 

[PhilT]

3 hours ago, Mk555blue said:

Does my approach make sense? It’s all a bit new to me. My original intention was just to install oil, but I don’t think that would be logical now. 

Difficult to say without knowing more about your situation. Will you be doing this yourself or are you talking about getting quotes for full installation options? If the latter, I was quoted £1500 for a 3kW split heat pump/air con for one room. Probably not the best quote but it gives you an idea. Do you have a max budget in mind?

What age, size and type of property is this, number of rooms, floor area etc?

[Mk555blue]

3 minutes ago, PhilT said:

Difficult to say without knowing more about your situation. Will you be doing this yourself or are you talking about getting quotes for full installation options? If the latter, I was quoted £1500 for a 3kW split heat pump/air con for one room. Probably not the best quote but it gives you an idea. Do you have a max budget in mind?

What age, size and type of property is this, number of rooms, floor area etc?

Thanks Phil. I keep reading different quotes so I need to get some of my own really. Max budget is really what will make the most economical sense, difficult for me to give a max as I’m really not sure on costs. This property is 1950s semi. 9 rooms in total. Does every room need a unit or does the blowing air heat up other rooms? Any advice appreciated. 

[PhilT]

22 minutes ago, Mk555blue said:

Thanks Phil. I keep reading different quotes so I need to get some of my own really. Max budget is really what will make the most economical sense, difficult for me to give a max as I’m really not sure on costs. This property is 1950s semi. 9 rooms in total. Does every room need a unit or does the blowing air heat up other rooms? Any advice appreciated. 

It's either one mini-split per room (1st photo), each room having an indoor blower and an outdoor heat pump/air con, or (2nd photo) one central heat pump/air con unit feeding however many indoor blowers for all the rooms you need heating. The first option involves an external unit hanging off the outside wall of every room - very unsightly, as well as being more challenging to install and maintain the upstairs units. The second option is neater but involves pipework installation around the house, and then you still need the DHW tank system in addition, so I would be surprised if a 9 room commercial installation is cheaper than a full hydronic system (net of grant) which, if well designed and installed, could be 30-50% more efficient. It's certainly worth a sustained research effort to get as many quotes and as much info as possible. The major energy suppliers such as Octopus are offering very competitive prices for hydronic systems, but their lead time can be very long and their offerings may not be available in certain areas.