Mixergy Hot Water tank

I’ve heard a lot about this new company recently, wondering if anyone has seen it, would it work well with bulb?

The idea is it changes the way it heats water so only heats what it needs therefore saving money and being more efficient .

Link below

https://mixergy.co.uk

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so only heats what it needs
Which is what my combi boiler does, I suspect any savings would take years for me to recover. Maybe it does have some merit but I am not qualified enough to be sure.
would it work well with bulb?

Can’t comment on the product, but to the specific point above - surely it is supplier agnostic and makes no difference.

It’s electric, so any energy it does consume will cost about three times as much as a gas fired boiler / tank set up. their own website says a typical 120 litre tank loses 1.04 kWh per 24 hours, and mixergy recon you can reduce this by 55%, saving you 0.57 kWh per day in otherwise lost heat, or about 5 pence worth of electricity. It just doesn’t make economic sense to switch, and certainly not to switch from gas heated water. On the other hand, if you have to replace an existing electric cylinder and have solar PV it may be justified, though devices are already available to “dump” surplus electricity from your panels into existing tanks. For my money it’s nothing more than a bit of greenwashed marketing.

it's nothing more than a bit of greenwashed marketing.
I read some more on another forum and the bottom line appears to be you would probably save a little but not much, a cheaper option being have another immersion element installed at the top of your existing tank, it may not be as `smart` but at least it wouldn't be heating water when you are not there.
On the other hand, if you have to replace an existing electric cylinder and have solar PV it may be justified, though devices are already available to "dump" surplus electricity from your panels into existing tanks. For my money it's nothing more than a bit of greenwashed marketing.
You'd be much better off installing a wet panel - far more efficient in heating up the water than PV and an immersion heater.

Assuming you’re all-electric, and heat your water during the night, you won’t see any significant gains by using that tech.

Why? because heat lost from the tank isn’t necessarily lost from the house - it heats the room it’s in, and diffuses through the rest of the property. Unless it’s summer, you probably don’t actually waste that energy. Secondly, hot water is a very tiny dent in your electricity bill compared to heating the entire house (£20 vs £140).

tl;dr: it would take much more than the lifetime of the tank to get your money back

it's nothing more than a bit of greenwashed marketing.
I read some more on another forum and the bottom line appears to be you would probably save a little but not much, a cheaper option being have another immersion element installed at the top of your existing tank, it may not be as `smart` but at least it wouldn't be heating water when you are not there.

Their own website gives the savings- albeit in a convoluted way and with no actual monetary value- it says savings of around half the heat usually “lost” from a cylinder can be saved. It goes on to say the typical heat loss over 24 hours is somewhere between 1 and 2 kWh depending on tank size. So a smaller tank, loosing 1 kw / 24 hours can expect to save about half a unit, so 5 or 6 pence a day. Practically nothing in other words.

It doesn’t matter if you “heat water when you’re not there” - that’s rateher the point of cylinders. The heat loss is so minimal, you heat when you anticipate demand and / or when power is cheap. A large tank will retain heat for days. Thank goodness the days of “sticking the immersion on” for an hour before we could have a bath are over!

On the other hand, if you have to replace an existing electric cylinder and have solar PV it may be justified, though devices are already available to "dump" surplus electricity from your panels into existing tanks. For my money it's nothing more than a bit of greenwashed marketing.
You'd be much better off installing a wet panel - far more efficient in heating up the water than PV and an immersion heater.

I agree completely- but my point was about those who have existing solar PV. They have more to gain by using their own generated power as completely as possible and a smart solar controller will help achieve this with minimal investment.

You'd be much better off installing a wet panel - far more efficient in heating up the water than PV and an immersion heater.

I agree completely- but my point was about those who have existing solar PV. They have more to gain by using their own generated power as completely as possible and a smart solar controller will help achieve this with minimal investment.

As the FiT is soon to be replaced by a competitive smart generation feed-in tariff, it may currently be a worthwhile investment installing an electric immersion (if you have a cylinder already) and smart controller, but may not be soon.

If you live in West London you can get one of these for free including installation from the below
https://peteproject.com/sign-up/
I did myself and must say it is an impressive piece of kit. The mobile app is really good. You can see how much hot water is currently in your tank and adjust accordingly from anywhere. Lots of stats and graphs available too. Easy to book heating schedules too.

Hi @topdrog, hello all. I’m a very satisfied Mixergy owner, so happy to answer questions.

Yes, it looks marvelous and works well with Bulb, but to be honest would work with any supplier - there’s no link between the two except that if you care about renewables and reducing your usage, they’re a great combination.

First, to dispel a slight misunderstanding for @Ed1178, the tank can be bought with a built-in immersion unit but in fact works just as well with your gas boiler (as an ‘indirect source’), so you can use either (or both). In fact we use ours with a new, efficient gas boiler at the moment.

While it is a modern design and therefore maybe loses heat slowly, this is not the main benefit.

The real benefit comes in two ways:

  1. the ‘only heat what you need’ makes a big difference. While most water tanks have to be fully heated to work, you literally only heat what you need at any given time. It means heating a much smaller quantity of water in an efficient way (not blasting with a combi in order to maintain pressure) when you need it. We only fill to 40% in order to have enough for 3 or more showers in the morning. It then waits until the evening and makes sure there’s a minimum available in case of rugby practice :wink:

    However, because it is also intelligent, it can be treated like a combi, so if your hot water drops below a certain minimum level, it kicks in to reheat enough to use.

  2. In combination with our solar PV (and an Eddi diverter) we use up any excess generated by heating the ‘buffer’ cold water in the tank. This is effectively a home battery as this lasts enough to avoid then having to heat any more water.

    This summer I don’t think the boiler kicked in once, and that’s for a family of 4!

The combined effect on my usage (of SPV, diverter, Mixergy) is that my annual consumption of electricity has dropped 24.9% and my annual gas by 15% (plus generating an extra £175 or more from the FiT).

It is hard to say what percentage was due to Mixergy and what to SPV, but by combining them you can certainly make the most of their individual benefits. The cost of the Mixergy is not actually that much more than a top of the range ‘dumb’ tank, so it would seem to make sense to me at least.

For full disclosure, I did take part in the Pete Project that @higgoboss mentions so I did benefit from a free tank, so feel free to ignore this as marketing - but it is a true personal opinion.

That project deserves a topic of its own since the idea is to coordinate all Mixergy boilers to act as network storage for excess renewable energy on the grid … so we are participating as test subjects as well. More on that another day.

Feel free to ask any other questions. I did have a bit of a problem with installation, so I can also give honest feedback on those rather practical matters if you are interested.