Do I need an Eddi, what does it do

k123456

I am considering a 10 or 12 panel system along with battery 5kwh , and battery ready inverter

I already have an analogue timer (brand is apt immersion heater controller)

I am open to correction, but planning to switch on by timer, the immersion, either at 3 to 5 am, (cheap EV tarrif) approx 8c per unit, or during the day , when sun is strongest, or perhaps from the battery

two people in house = 2 showers a day

I also have the option to use my 4 zone gas system to heat water to HW zone

The water tank is big , , label on is it unvented indirect solar cylinder 300 litre

What will the Eddi do for me, do I need one

One or two installers have said they are unreliable, not sure how true that is

Not sure if relevant to my questions, but I thought I would add

1 Have a 28kwh EV, non smart wall charger, however there is a timer function on the car, which the car charges after mid night, when rates are low

I dont drive a lot , so usually charge it once a week from 30% battery capacity to full

1. 2.....10 panels exceeds my annual usage , so will be selling back to the grid at 24c per unit
2. 
   
3. House empty 9 to 5 Mon to Friday DW and WM have timers , so can have them run at any time

Tree

a) probably not*

b) Heats water according to the amount it sees exporting so it soaks up energy isntead of exporting.

Doesn't need to be attached to an immersion but that's the main use case. I like mine cause I'm lazy and it makes automations really easy (got mine installed before FIT was even confirmed). You can get a different smart switch to control from other automation hub if you want the nice lazy option. Eddi does do nice variable power but like, if you're heating at night you don't need that.

ian123

I have an EDDI installed, but am getting rid of it. It barely worked for me due to the immersion heating element being very short, sitting in the top of a large 300L cylinder. The EDDI would divert to the immersion and give up after 15 mins. The thermostat was in the top of the tank, and once it reached 70C it would cut off - leaving about 80-90% of the tank with cold water.

I could have replaced the cylinder, but i have gas (2 zones + hot water) and paying to get a complete cylinder replacement with updated immersion was not worthwhile.

Jonathan

https://www.boards.ie/discussion/comment/121858293#Comment_121858293

None of that is an issue with the Eddi though. You'd have the same issues with an Eddi or a dumb timer switch.

J_R

https://www.boards.ie/discussion/comment/121858293#Comment_121858293

You just need a "Willis". This is an external heater installed outside the tank. Costs around €50 or thereabouts. (+ plumber)

Works great. Quick Google for explanation https://www.elemex.ie/external-immersion-heater/

SharkMX

My dad has an Eddi. I wouldnt get one if i was ordering a system now. Just get a cheaper timed wifi switch and just heat the water from the night rate and export excess and if you have excess solar in the day and want more hot water just switch it on from your phone for an hour and it will use the solar. Or go to the hotpress if you dont want remote functionality.

k123456

https://www.boards.ie/discussion/comment/121882113#Comment_121882113

Thanks for that have an analogue switch/timer , but i Can see the benefits of wifi version. Originally I thought , no point in overheating the water to over 40c, however apparently that's not a good idea, needs to be heated occasionally to 60 c

graememk

https://www.boards.ie/discussion/comment/121882401#Comment_121882401

Obligatory heat geek legionella video

https://youtu.be/oJeyc_cGIMU?si=aAY4ri7Ugf1apCTj

ZMOONY

https://www.boards.ie/discussion/comment/121882401#Comment_121882401

legionnairees

Deagol

Have an Eddi and it's perfectly reliable. I bought the optional board and a couple of thermocouples so now I can see if there's enough hot water for a shower any time on my phone. I can also turn on (force heat) the tank if I need remotely.

But biggest plus for me, is that during the spring / summer / autumn, I don't need to spend anything heating hot water. My 6.1kw solar system keeps the water hot in the tank using any excess electricity from the panels. Its very rare from about end of March to end of September for me to have to spend a penny heating water.

Whether it's financially worth having one or not, I love my Eddi! I did do some maths on it and it's probably close to cost neutral if it lasts 10 years. But the convenience of it means I'd happily have another even if it cost me.

CramCycle

I have one and it is great. Keeps the water hot for 2/3 of the year, more than enough for family of 3 and takes the chill out for the rest of the time so that it only takes a few minutes to heat up fully when needed.

As others have said, check where the entry point to the tank for your immersion is, no point doing it if it is at the top of the tank (who designed this tank?).

But i would recommend it.

Handy for your battery system, charge it up and then the hot water during the summer months, switch to a timer to charge them over night in the winter months.

k123456

I am going for 14 panels and 5kwh battery , however it does occur to me , does anyone go for a large battery lets say 15khw, no panels, charge the battery at 6 to 8c a unit on an EV rate 2 to 5 am, and then use the stored power to power the house ?

Latro

You can have exactly the same functionality or perhaps even better for a fraction of a cost.

I use Sonoff ZigBee bridge + ZigBee 20 Amp switch + Home assistant with automation set up for EV tariff and excess solar.

AmpMan

https://www.boards.ie/discussion/comment/121885488#Comment_121885488

No where near the same functionality as an eddi.

randombar

I've one for sale on adverts if anyone is interested. Installed a heat pump and already have solar thermal so no real requirement any more.

k123456

https://www.boards.ie/discussion/comment/121882113#Comment_121882113

Can anyone recommend please timed wifi switch , please

graememk

https://www.boards.ie/discussion/comment/121888156#Comment_121888156

Mines something like this

https://www.amazon.co.uk/Immersion-Heater-Switch-2-4Ghz-Compatible/dp/B0C1Z6FVWC/

loyatemu

I've just ordered solar and asked them to take the Eddi out of the offer and replace it with extra panels. I can heat water for ~10c per kWh with gas whereas I'll get paid 18c for excess solar. So from a purely financial perspective the Eddi makes no sense. If I change my mind either through environmental guilt or because the FIT rates change/disappear I reckon I can replicate the functionality for a fraction of the cost of the Eddi.

SharkMX

https://www.boards.ie/discussion/comment/121889040#Comment_121889040

That one linked above by graememk can be set to heat the water the night before if its cloudy or heat it during the day from the solar if its sunny with the standard automation. But if you had home assistant set up you could nearly get it to sing when the sun is out and snore when its not.

k123456

https://www.boards.ie/discussion/comment/121889040#Comment_121889040

Thats a good point about the FIT rates, I wonder how long we will have these rates, which I think are 18 to 24 per unit, a lot lower in the UK https://www.comparethemarket.com/energy/content/feed-in-energy-tariffs/

loyatemu

https://www.boards.ie/discussion/comment/121891223#Comment_121891223

they'll reduce as electricity rates come back down. But so will gas rates (I was paying around 3c a unit for gas not too long ago)

One of the guys I met to give me a quote for solar told me that in some European countries they've moved to dynamic FIT, and at certain times they charge you to feed into the grid as they have too much solar. He reckoned the same will happen here.

But another guy I met said this was years away and he probably has a point - when I was in Belgium last year I'd say 70% of houses have panels on their roofs. I was on the Dart this week looking at the housing estates beside the line in Shankill, and in some of them I couldn't see a single solar panel. On my road of 20 houses, there's one with solar tubes and that's it. Now, most of my neighbours are 70+ which would explain that, but take-up of rooftop solar is still very low in Ireland compared to other countries.

Lewis_Benson

The eddi is a great addition imo.

On good sunny days I have a full tank of hot water by 10am, and then feed out tonthe grid for the rest of the day, if the temp needs a top up it will get it as needed.

yknaa

Lads, if I turn off my Eddii due to being away from the home for a period, does the excess energy go straight to the grid if you don't have a battery? Is it worth doing if going on holiday I wonder? Thanks

Tree

Yup, and you can turn it back on the day before you get back using the app so no waiting for it to heat up again

AGC22

Apologies in advance if this is wrong place for this question. Happy to start a new thread if needed.

I have solar a few years now, but no EDDI as I've a thermodynamic panel for hot water. I don't have a heat pump either.

Friends are asking me advice about a solar install. They have a heat pump already. Should they get the EDDI with solar install, would it make sense with heat pump?

I've read some people have heat pump set to work at hi temps at night during cheaper grid rates, maybe that's the solution and ignore EDDI?

Appreciate some advice please.

SharkMX

https://www.boards.ie/discussion/comment/121895566#Comment_121895566

Scroll up and you will see lots of peoples views on it

graememk

https://www.boards.ie/discussion/comment/121895566#Comment_121895566

Thermodynamic panel.. is a heat pump btw.

But yes your right, no point your friends shouldn't get an eddi.

An Eddi is 1kWh of solar (electric ) to 1kWh of heat into the domestic hot water.

A heatpump when heating DHW can use 1kWh of electricity and gets 2-3 kWh of heat into the DHW. Some heat pump systems are also incompatible with an Eddi as the heat pump controls the immersion.

An Eddi is just a immersion controller

Yes you can then also use night rate to get water at a cheaper rate too

JayBee66

I wouldn't recommend an EDDI. It's too blunt an instrument.

To me an EDDI is an expensive one trick pony. All it does is divert exportable energy to one or two resistive devices (e.g. immersion heater or other resistive heater)

By running some form of home automation (e.g. Home Assistant) then you can monitor energy export and use the excess for all manner of things. (e.g. dehumidification)

If you have or plan to have electric heating in the winter (e.g. heat pump or resistive heaters to replace some fuel burning) then you will want to export all you can. An EDDI will eat into the credit payments from your electricity supplier, which would be better used for reducing the price of your heating bill.

Scalding hot water everyday is a waste. During the winter, I have a TimeGuard immersion switch that comes on for half an hour in the morning (shower is electric not from hot water cylinder), using night rate electricity and that's usually good enough. If not then a quick boost when the sun has filled the battery.

It seems that a lot of installers are slow to react to change. An EDDI might have been useful before FIT. Now, not so. The electrician and roofer who worked on my install didn't even have PV on their own homes so if they recommended EDDI it would have been through following a script.

AmpMan

I've an eddi.

I've also only pumped showers & a big well insulated HWT.

If had electric showers then no way would I buy one (at full price).

slave1

Currently an EDDI is worth it under various circumstances

Off Grid, soak up excess

Over producing and clipping export, soak up excess (e.g. NC6 filed but generating way more)

Uber convenience if you have a Zappi through the excellent and simple MyEnergi app which is very easy to use from anywhere

If a new install, then you already have electrician there to fit it

Avoids Home Automation route which is a bridge too far for many

Also, it allows temperature monitoring in the App via optional temp sensor relay and probes, easy DIY after fit, makes it very easy to see whether you need to boost the temperature for example an evening shower

What has impacted the "worth" of an EDDI is the current FIT rate, I totally agree but that is with current FIT which is artificially high and can only go one way. There was much talk before FIT on this forum and we were all saying around 4c, some said maybe 8c/9c so we were all (happily) taken back when the rates came in. They are already reducing and in a year or so might have continued the trend down to where we expected them to be. Then likes of an EDDI will be back as viable and folk looking to retrofit.

PV is an evolving world, DIY battery prices have plummeted, FIT is mad high, installers are reefing us out of it, change change change

As more and more of us get PV I can see ESB Networks restricting export capacity further, thankfully I am first on my row with an NC6, there are now 4 others

AGC22

Thanks all for your comments. I'll digest and share with my friends.

Agree the FIT rates likely to drop so EDDI should become worth it over time. Albeit not sure if friends heat pump system and whether compatible.

Latro

https://www.boards.ie/discussion/comment/121887181#Comment_121887181

I've never had Eddi so I don't really know what are its capabilities, but It is hard to think what it could potentially do more than Home Assistant automation.

HA will fully control your Immersion heaters based on any criteria you can come up with. Time, excess solar, temperature, house load, you name it.

If you get switch relay like Sonoff 320D with temperature probe sensor it will also add a layer of protection for water overheating, in case your immersion thermostat fails for some reason.

Total cost would probably be around 30 euro for zigbee bridge + 30 euro relay per immersion + whatever you decide to run your HA assistant on but I'm sure almost anyone has a few years old laptop collecting dust somewhere.

What if Eddi dies in 3-4 years? Will you fork out another 500 for replacement?

Why would you heat water on the excess solar anyway? It doesn't make much sense with the current generous FIT rate.

The only scenario comes to my mind if you have 2 inverters with export cap at 5/6kW under NC6, and if there is still free capacity above that.

But then again HA is perfect for that.

AmpMan

Can you send 1kw to the immersion with home assistant?

Or 500watts to a 2kw heater ?

graememk

https://www.boards.ie/discussion/comment/121904674#Comment_121904674

The big thing about the eddi/immersion diverters is that they can vary the power the immersion takes.

It's not on/off like home assistant can do.

Rest of the points still valid.

TheBigBadWolf

Hi, newbie question.
I’m getting (18) panels installed. We don’t have a heat pump (have a gas supply). Also getting a battery.

Is it still worthwhile getting an Eddy if you have a battery or is there no point?

graememk

https://www.boards.ie/discussion/comment/122059723#Comment_122059723

You can heat water for 10c/kWh with gas,

You can sell your electric for 20c-24c/kWh.

yankinlk

Ive a smallish 5kw battery and an eddi. I love mine for the convenience. 2 adults 2 teens pumped shower means we always have timed hot water for normal scheduled and the simple boost button all of them understand how to use if they have a 3rd shower after the gym at an unusual time … but mostly i have constant hot water all year round. Cost to run is negligible in winter (small tank ) heats very quick.

Electric showers kept under 10 minutes are much cheaper but then you havent met a teenager have you.

millb

https://www.boards.ie/discussion/comment/121882113#Comment_121882113

Agreed - the Eddi was useful pre FIT.

They are not needed in times of positive FIT and cheap night tariffs.

May become useful again if / when daytime PV export goes to <10 or 15c.

I use mine now as a timer (on@4am) and with the remote boost (eg 8pm) when needed.