Iboost - yes or no

pw22

Am thinking about adding an i-boost to our system - we have been quoted £289 for supply and install.

There seem to be various threads on here both for and against. If you have an i-boost or something similar, has it been worth the investment?

Thanks everyone

JimLad

pw22 wrote: »

Am thinking about adding an i-boost to our system - we have been quoted £289 for supply and install.

There seem to be various threads on here both for and against. If you have an i-boost or something similar, has it been worth the investment?

Thanks everyone

We have one....for 6 months of the year 80% of the time we use no gas whatsoever. Watch out for those daily standing gas charges!

At £289 for installation its going to take a long time to pay back. Ours was installed along with our panels so not sure how much we paid really as there was no breakdown. It was £5750 for a 4kw system, iboost and a geo energy monitor which when you look at other quotes on here is about average now.

pinnks

I have the Immersun, which is more expensive but does the same basic job. I too turn the gas off for 5+ months a year saving about £75 or so. I also get some added savings over the winter months but difficult to quantify when the heating is also on.


I also use the second and third outputs to power oil-filled radiators which help take the chill off the living room during (mainly) the afternoon once the water is hot (though you could set the system up to each output an equal she of the available surplus). This means the heating is on less in March/April and October/November.


So, well worth the investment in my view and should repay itself within about 3 - 5 years. Mine cost £350 at the time of PV install and has already repaid over a third in 20 months.

hubr

Worth it, just for the smug feeling that you're doing all you (reasonably) can before exporting electricity! Like others, I found I could largely dispense with gas water heating in the sunnier months. I take the view that despite the usual short guarantee period, repairs may not be frequently needed, especially if the i-boost is located in as cool a spot as possible. Anyway, with the numbers of these & similar, there's certain to be competitive repairs, later on. Mine was also supplied within the installation bundle, at similar price to yours. No regrets.

nigelpm

Short simple answer at £289 is No.

You will never recoup your initial investment.

Long answer is there might be other considerations but anything above £200 is going to be tricky to justify.

nigelpm

pinnks wrote: »

So, well worth the investment in my view and should repay itself within about 3 - 5 years. Mine cost £350 at the time of PV install and has already repaid over a third in 20 months.

I'd love to see your figures on this. I think you are way off.

nigelpm

My reasoning :

I guess the question is how much of that diverted energy is useful comes into play.

I've no doubt you could divert around 1,200 Kw/h in a good year but not useful if you only make use of 75% of it.

So say 1,000 Kw/h per year on the generous side at 4p (gas cost) + 1p for inefficiencies in system gives you £50 a year.

These things are built to last 3-5 years.

Like I say might just work for people at £200 - £250 but much more and I doubt it makes economic sense.

Minrich

nigelpm wrote: »

My reasoning :

I guess the question is how much of that diverted energy is useful comes into play.

I've no doubt you could divert around 1,200 Kw/h in a good year but not useful if you only make use of 75% of it.

So say 1,000 Kw/h per year on the generous side at 4p (gas cost) + 1p for inefficiencies in system gives you £50 a year.

These things are built to last 3-5 years.

Like I say might just work for people at £200 - £250 but much more and I doubt it makes economic sense.

Where do you get the lifespan of the iboost/immersun from ?

nigelpm

Minrich wrote: »

Where do you get the lifespan of the iboost/immersun from ?

Guarantee lasts for two years. It's a cheap bit of kit. Double that. Get four years on average.

Clearly this isn't scientific but you have to assume a certain lifespan with anything.

If the lifespan is >5yrs then anything below £250 becomes economic.

Dave_Fowler

Without the immersion controller, I would normally heat my hot water using a relatively new efficient gas boiler. Using a gas cost of 3p/kWh, during the 5 summer months, May to September I've saved £39 per year for the last two years compared with the previous year (before the controller was fitted). During these five months, the central heating is usually off so the calculations are relatively uncomplicated.

Calculating the amount saved during the remainder of the year is difficult as the reduced gas usage is masked by the central heating requirements which varies greatly depending on the weather.

However I have shown that, for our hot water requirements, any day when I've generated over 8kWh I do not need to heat the water any more.

How much you save during the winter using the immersion controller depends very much on how large your PV system is and therefore how much spare power you have.

For my 6kWp system there aren't very many days during the winter when I don't achieve 1.3 Os (42 in the past 7 winter months). Rounding this up and assuming that for 2 of the 7 winter months the PV failed to produce any hot water saving, I could still reasonably claim that I've saved a further £39 during 5 of the winter months.

So for me that's £78 per year minimum. I am very fortunate in that I was able to design, build and install my own controller for a cost of around £140 - so it has already paid for itself.

Dave F

Minrich

nigelpm wrote: »

Guarantee lasts for two years. It's a cheap bit of kit. Double that. Get four years on average.

Clearly this isn't scientific but you have to assume a certain lifespan with anything.

If the lifespan is >5yrs then anything below £250 becomes economic.

What is there to go wrong with it ? Its just a glorified switch afterall.

Who says its a cheap bit of kit ?