Solar iboost installation 13 December 2014 at 5:28PM in Green & ethical MoneySaving 54 replies 25.7K views

pete1968_2

I have recently had a 2.65KW solar PV system installed and am considering a solar iboost water heater. My current immersion heater is 3kw. At the moment I am generating approx 2-3KW a day and exporting most of it as no one is in the property during the day. I have periodically checked the power out put from the panels and they are generating up to 1.3kw at a time in the day.


Do I need to change my immersion heater to 1kw or will the 3kw one do. I don't really understand how it works. Could someone kindly explain for me please. Thanks

legoman62

pete1968 wrote: »

I have recently had a 2.65KW solar PV system installed and am considering a solar iboost water heater. My current immersion heater is 3kw. At the moment I am generating approx 2-3KW a day and exporting most of it as no one is in the property during the day. I have periodically checked the power out put from the panels and they are generating up to 1.3kw at a time in the day.


Do I need to change my immersion heater to 1kw or will the 3kw one do. I don't really understand how it works. Could someone kindly explain for me please. Thanks

It will work with a 2.65kWh system.

Not sure how much you will get, dependant on house baseload.

The Solar iboost diverts any excess solar power to the immersion heater.

I'm not using an iboost, but my device does the same.

I would also turn your immersion stat up and the cylinder stat down:cool:

(immersion temp set higher than cyl stat temp)

Edit.

Most of the people I know, negotiated a deal with the iboost thrown in:think:

pete1968_2

So in laymans term, the 1kw or so surplus I have will still cause the 3kw immersion heater to heat albeit at a lower wattage?


Thanks for your reply

Sterlingtimes

Today, I generated around 6kWh and the iBoost grabbed 2 kWh. I am not sure about the payback period but installers appears to be throwing them into deals. Must be reasonably cheap for solar installers.

pete1968_2

My installer wanted £530 to supply and install. I've bought one off e-bay for £210


Just checked my inverter and I have generated 5.677kwh today

legoman62

pete1968 wrote: »

So in lay mans term, the 1kw or so surplus I have will still cause the 3kw immersion heater to heat albeit at a lower wattage?


Thanks for your reply

Should divert any excess.

Read-out gives daily,weekly,monthly and total saved.

Cost about £200ish.

You could ask your installer for a price to fit one in for you?:cool:

Edit.
Just seen your 5.15pm post. Do you know a leccy who could fit it...looks fairly easy:D

chris329a

pete1968 wrote: »

So in laymans term, the 1kw or so surplus I have will still cause the 3kw immersion heater to heat albeit at a lower wattage?


Thanks for your reply

Yes - if there is 500w excess it diverts that. It fluctuates depending on the excess until hot and then obviously it stops. I personally think it's the best bit of kit to compliment the PV as you just leave it to do it's stuff knowing that if the clouds move it will automatically use the excess to heat the water. Seems easy to fit from the immersion heater switch to the heater itself.

Sterlingtimes

I think that I might install an "export light" outside of the airing cupboard to indicate when generating is exceeding normal usage.

JimLad

Sterlingtimes wrote: »

I think that I might install an "export light" outside of the airing cupboard to indicate when generating is exceeding normal usage.

Thats a great idea. Im always opening up the cupboard to see if im iboosting!

nigelpm

pete1968 wrote: »

My installer wanted £530 to supply and install. I've bought one off e-bay for £210


Just checked my inverter and I have generated 5.677kwh today

My rough calculation when I did the maths reckoned I'd save roughly 800Kw/h over the year - albeit I discounted the winter months as generally the gas central heating would be on and thus heating the water anyway.

800Kw/h at a small premium (1p) to gas price (4p a Kw/h) for wear/tear of boiler gives (800*0.05) = £40 per annum.

I'd argue the life of these are probably 4-5 years max so anything over £200 is probably too much.

Just my opinion - happy to hear other thoughts on this.

Sterlingtimes

nigelpm wrote: »

... 800Kw/h at a small premium (1p) to gas price (4p a Kw/h) for wear/tear of boiler gives (800*0.05) = £40 per annum.

I'd argue the life of these are probably 4-5 years max so anything over £200 is probably too much.

Just my opinion - happy to hear other thoughts on this.

Oh dear. My expectation was better, but no experience at yet. In three of the months when I use no central heating radiators, the water and a little gas cooking uses 650 kWh of gas in each month. My hope was that the iBoost output would cover most of that. We are heavy showers in the Sterling household.