Do immersun type devices work

[robertevans68]

Hi, I'm new on here and am having a 4kw pv system installed this week.
I obviously want to get the most from my purchase and have been searching for ideas, one of the best things i can see is the immersun. Is there any other similar devices I should look at or do these type of devices work?

Thanks Rob

 

[Gavin A]

Immersun work well, I can't speak for any of the other products, but we checked them all out a few weeks ago before determining that Immersun seemed to be the best on the market at a reasonable price.

 

[sedgy34]

Will segen or Krannich sell these units a recent customer may benefit from one

 

[FB.]

Immersun work well, I can't speak for any of the other products, but we checked them all out a few weeks ago before determining that Immersun seemed to be the best on the market at a reasonable price.

And the cost if the unit is.........?

I also note in the manual that it says:
"......Do not attempt to wire this unit if you are not a qualified or an experienced electrician....."

And how much more would that add to the cost, if people have to get an electrician to fit it?

 

[sedgy34]

And the cost if the unit is.........?

I also note in the manual that it says:
"......Do not attempt to wire this unit if you are not a qualified or an experienced electrician....."

And how much more would that add to the cost, if people have to get an electrician to fit it?

Speak to your installer if they are still around

 

[FB.]

Speak to your installer if they are still around

Can give just a vague indication on what a customer should expect for pricing?
Lack of information just encourages people to do nothing and lose interest, which is what I'm now inclined to do, as I expect the secrecy on pricing means that it can be very expensive.

 

[BruceB]

google 'immersun price' and there are at least a couple of hits with prices, including a contributor here.

 

[Gavin A]

indeed... Immersun installed price from £499

which I think is relatively standard for a straightforward installation.

 

[sedgy34]

Can give just a vague indication on what a customer should expect for pricing?
Lack of information just encourages people to do nothing and lose interest, which is what I'm now inclined to do, as I expect the secrecy on pricing means that it can be very expensive.

I would imagine you are looking to pay the cost of the immersun unit and around £80/100 for a sparky to wire it in.

 

[MicraShed]

indeed... Immersun installed price from £499

which I think is relatively standard for a straightforward installation.

Thats what I have been quoted plus a bit extra because Im outside the usual coverage area for te installer. I need to sort out a date for an install with them actually but Ive been in and out of damn hospital again this week.

Given the cost of the unit is roundabout the £380 - £400 mark from the company that makes them from what I did find out (Google be your friend here).
Add in materials (cable etc), travelling, VAT and other sundries then another £99 on top isnt really that bad for a qualified spark to fit it. Whilst it might sound a fair wedge for a box of bits, having researched the unit (all-right so far it does seem to be anecdotal evidence) they do two things - the make sure almost every scrap of electric you generate is used, and they reduce the energy (gas or electric) you use to heat your water.
Now for me, given that my domestic gas use is pretty much entirely water heating use between about March time and October time and given that Im using about 14kW/day between these months of gas.

So, gas at about 4.1p/kWh x 14kWh x 210 days (appx) = £120.40

Potentially in the months where I dont have the heating on for anything other than hot water that is a saving of £120. There should be additional savings through the year as well, so the "payback" time for me at least will be about 3 to 4 years, possibly less.

These are only rough calculations of course, but it certainly seems a viable proposition. My only concern is whether or not there are any "moving" parts (eg, power relay) that might have a limited lifespan and need maintaining during the payback period.

Of course I could be talking out of my bum here, so I welcome other peoples thoughts or experiences.

 

[robertevans68]

Thanks for the replies. I've been quoted £359 for the unit

Rob

 

[Worcester]

3 to 4 years is about right, if you are on oil it'll be less.

Plus you can add in an addtional device, we have yet another installation going in next week doing just that, Immersun + 3 x Dimplex DXLWP800. Other heating is an oil fired rayburn, so once the immersion is up to temp, the goal is then to send the output to these just to take the chill off one of the bedrooms and extended hallway, as that part of the bungalow acts as a 'heat sink'. Base price as above plus e/o for the heaters, trunking, cabling isolators and time, though being a bungalow with good loft access, the extra time shouldn't be more than an hour, and customer is happy with / suggested surface mount trunking. - oh and yet again this is an installtion that we didn't do, they approached their original installer first who wasn't interested!

If you want a local installer go to Where to Buy :: immerSUN :: Use 100% generated free electricity :: A 4eco Product look closely and you find a lot of senior forum members listed as installers!

 

[FB.]

Immersun + 3 x Dimplex DXLWP800.......the goal is then to send the output to these just to take the chill off one of the bedrooms and extended hallway!

Yes, you've no doubt seen my topic relating to my central heating, and in the cooler weather earlier this year, we have been using a couple of 500W electric conservatory heaters to boost the lounge temperature when the 3.75kWp solar is producing well.
With the gas and electric tariff's we're on, and the 75% efficiency of my boiler v 100% efficiency of an electric heater, the cost of electric works out about is about 1.7x that of gas.
So as long as the solar can contibute about 250W, a 500W heater is no more expensive to run than the central heating; and probably cheaper if it's just a degree or two extra heat required in one or two rooms. Not to mention the 95W central heating pump's power consumption, the boiler's power consumption and losses through the pipes in the walls and between the floors.

In fact, my earlier interest in Immersun was the possibility of adding an additional socket in the lounge (we would really benefit from one more socket and the CU is on the other side of the lounge wall), and have that socket as a surplus solar electricity dumping point.

 

[MicraShed]

In fact, my earlier interest in Immersun was the possibility of adding an additional socket in the lounge (we would really benefit from one more socket), and have that socket as a solar electricity dumping point.

Wouldnt the load have to be resistive though and not inductive? How could you be sure that whatever was plugged in would be a resistive load - also, would the Immersun dump to the socket if there was no load detected? I dont think it would.

 

[FB.]

Wouldnt the load have to be resistive though and not inductive? How could you be sure that whatever was plugged in would be a resistive load - also, would the Immersun dump to the socket if there was no load detected? I dont think it would.

Yes, it would have to be certain types of load on the socket (and labelled appropriately), and if nothing was connected the power would be lost to the grid.
Perhaps split between a 1-2kW immersion element and a dump-socket in the lounge.
I've seen lower-powered immersion elements here (but have not dealt with them, nor do I know anyone else who has, so I can't vouch for the company):
Immersion Heaters from Surejust

 

[robertevans68]

Hi,
So basicly I could use an immersun to run a 1kw immersion and a couple of heaters in bedrooms, if total load is less than 3kw?

Thanks Rob

 

[Worcester]

Yes, or use your exisiting 3 kw Immersion and when that is up to temperature let it roll over on to the heaters, or if you have a very large system PV and low base load, you can link two immersuns together to control up to 6kW proportionally.

If you link up 1kW immersion and 2 x 800W heaters on the same circuit, at the same time as you suggest, when the 'spare' output from the PV system is 1.3 kW then 500W will go to the immersion and 400W to each of the heaters. so the water will take loner to heat up, and you may just get everything luke warm.
Also if you wire a 1 kW immersion in 'roll over' mode, will take a lot longer to heat if you have spare PV generation > 1kW as the immersion won't take more that 1 kW.

 

[liquidity]

Thats what I have been quoted plus a bit extra because Im outside the usual coverage area for te installer. I need to sort out a date for an install with them actually but Ive been in and out of damn hospital again this week.

Given the cost of the unit is roundabout the £380 - £400 mark from the company that makes them from what I did find out (Google be your friend here).
Add in materials (cable etc), travelling, VAT and other sundries then another £99 on top isnt really that bad for a qualified spark to fit it. Whilst it might sound a fair wedge for a box of bits, having researched the unit (all-right so far it does seem to be anecdotal evidence) they do two things - the make sure almost every scrap of electric you generate is used, and they reduce the energy (gas or electric) you use to heat your water.
Now for me, given that my domestic gas use is pretty much entirely water heating use between about March time and October time and given that Im using about 14kW/day between these months of gas.

So, gas at about 4.1p/kWh x 14kWh x 210 days (appx) = £120.40

Potentially in the months where I dont have the heating on for anything other than hot water that is a saving of £120. There should be additional savings through the year as well, so the "payback" time for me at least will be about 3 to 4 years, possibly less.

These are only rough calculations of course, but it certainly seems a viable proposition. My only concern is whether or not there are any "moving" parts (eg, power relay) that might have a limited lifespan and need maintaining during the payback period.

Of course I could be talking out of my bum here, so I welcome other peoples thoughts or experiences.

The only flaw I can see in your calculations is perhaps not factoring in what time of the day the gas use takes place. Although I have never looked at the meter on a typical day I suspect most of my gas use takes place in the morning, first as the hot water is brought back up to temperature after cooling overnight, then after the first shower and then once more after the 2nd shower. These showers typically take place before 09:00 5 days a week when most PV systems will only have produced a few kWh. And even if a 4 kWp system is running at 100% at 08:00 it still isn't pouring as much heat into the hot water tank as your boiler will so the reheat time will be longer.

The surplus kWh from PV will help cover the cost of any hot water use during the day and early evening though.

Thus I think the payback time for something like the Immersun will be considerably greater for my hot water use profile which is probably not far different than many people's.

 

[Gavin A]

insulate your tank properly though and the water should remain hot overnight from the previous days heating.

 

[FB.]

insulate your tank properly though and the water should remain hot overnight from the previous days heating.

Our hot water tank (3kW element, about average tank size) was without a jacket for a while earlier this year.

From almost cold, without the jacket (a basic red B&Q/Homebase-type), the heating time was about 75 minutes. With the jacket it was about 45 minutes.

If the hot water was unused, the amount of time before it began reheating went from about 75 minutes without the jacket, to about 120 minutes with the jacket.

In other words: by having a boiler jacket, the heating time was almost halved, and the time before reheating was almost halved. Half as much power usage to heat it, and half as much power usage to maintain it at a hot temperature.

So for those who don't have one; £10-15 for a boiler jacket should pay for itself after just several weeks.