Iboost/immerSUN installation costs

eyeofthetiger999

Hi Everyone.
I have had a 4kw solar PV installed for almost 1 year now and like others, I am now looking to maximise the best use of out of it. I have a powermax gas boiler(rated D) and my gas bill per year is £38 per month. I do not have an immersion heater but am interested in the benefits of potentially free heated water but have some questions that I would be interested to hear from fellow users who have had an immerSUN/iboost system installed:

1) What cost would you estimate to have an immersion heater with system to divert solar power(parts+labour)?
2) What are your potential savings?(or how much would I save per year)?
3) In your opinion is it worth having this done or would the costs be too high for the savings earned?

Thanks

Cardew

I doubt it is possible.


http://www.miketheboilerman.com/powermax.htm

EricMears

I couldn't see any reference in Cardew's link to the Powermax system having any provision for an immersion heater element.

To fit one, you'd almost certainly have to replace the hot water storage tank which (since they're 'integrated') would also mean changing the boiler.

That makes the problem very similar to a recent thread
https://forums.moneysavingexpert.com/discussion/5361228
in which costs of cylinder were touched upon.

Without bothering to try a more accurate estimate, my ball park figure for a new boiler, new tank , immersion heater and diverter device would be somewhere in excess of £2,000 and if it's not a DIY project probably another £1000 to employ a plumber &/or electrician.

Perhaps not quite 'impossible' - but far from 'worthwhile' !

Cardew

As just posted in another thread, assuming you could get an immersion heater and if you managed to divert 1,000kWh pa to that heater, with gas CH it would represent a saving in the region of £40pa.


Perhaps some posters here have a kWh figure of how much was diverted in a year. Whilst on a brilliant cloudless day there might be 20kWh excess, there is a limit to how much could be put into a HW tank. IIRC to raise a 150 litre tank from 15C to 65C would take around 10kWh.


So I would be surprised if the transfer was in excess of 1,000kWhpa.

Sterlingtimes

837 kWh diverted per year
System calculation means gas heating of hot water is 50% efficient
Therefore 837 * 2 = 1,674 kWh of gas displaced.
Saving per annum 1,674 * .0302 = £50.55

However, in my case loss of export income is 837 * .0485 = £40.58.

Net benefit £50.55 - £40.85 = £9.70

Pay back is about 30 years.

pinnks

I divert about 750kWh per year based on 29 months of data. But don't forget the losses in the pipes when using the boiler over the summer only for hot water. I have a round trip of about 20m of 28/22mm copper (not insulated or able to be so without significant upheaval), end up heating the floor upstairs rather than only the tank.

My gas is off over the summer and saves me about £70-£80 based on pre-immerSUN records. Over the winter months the immerSUN will provide a little pre-heating and save perhaps another £10 or maybe £20?

My system was installed free (negotiated after I got my quote agreed) and cost £250, so payback will be after about 3 years.