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mavison
Rank 2
March 12, 2023
Solved

Is immersion heating as efficient as the gas boiler for heating the water? I'm trying to work our solar savings...

  • March 12, 2023
  • 11 replies
  • 4974 views

We have recently had solar pv fitted, with iBoost on the hot water tank to use any generation excess.

I am trying to get a figure for the savings made by using the solar pv to heat the hot water rather than the central heating gas boiler. There is a 3-way valve to control rads & hot water separately. This raises the question:

Does 1 kWh of immersion heating produce roughly the same amount of hot water as 1kWh of a gas boiler heating the water? I realise it will not be identical due to efficiencies and losses, but are they similar?

I hope to be able to compare costs of heating hot water by pv or gas, ie loss of SEG payment vs gas rate.

Then I will know the savings to be made.

Best answer by mavison
 
@Jonathanprentice You can regard the immersion with iBoost as another energy storage device like the battery - they both can store surplus PV power. The difference is that the energy stored in the battery is used as electricity, the energy in the immersion is used as hot water. When neither battery nor immersion are full, any surplus PV may first go to one or the other, depending on setup. Here it first goes to the battery, but when 80%? plus some also goes to the immersion. Only when they are both full is any significant surplus amout exported.

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Rank 5
Jonathanprentice
Rank 5
August 21, 2023

See https://www.marlec.co.uk/solar-iboost-downloads/ where you can download from the Technical Support area the User Manual and the Installation Instructions. You should find details in there.

Is that another CT clamp I see there already?


That is the feed from the solar system. 

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OVO Energy Ltd, Floor 5, Crescent, Temple Back, Redcliffe, BS1 6EZ, (Company no. 06890795) registered in England and Wales.

OVO (S) Gas Limited is registered in England and Wales (Company No. 02716495) at Floor 5, Crescent, Temple Back, Redcliffe, BS1 6EZ.

OVO (S) Gas Limited is part of OVO Group Ltd