How much solar would you like?

What kind of roof do you have?

In what year was your house built?

doesn't have to be exact

What is your building energy rating?

(if you know it)

Contact info

We keep your details secure and never share the with installers unless you request to be contacted by them

We'll send your quotes to this email addres so please make sure it's correct^^

NPV Calculator Formula

The Solar NPV calculator is based on the formula:

Formula for the net present value (NPV) of a solar energy system.


-C_Rep over ( 1 + i ) ^ 15

+ sum from{t = 0} to{p -1} G_1 times(( P_S X S) + (P_E times (1 - S)))X (1 + i_e)^t X( 1 - d )^t / ( 1 - i )^t


NPV = Net Present Value
CIns = Installation Cost
CRep = Cost to replace the inverter at year 15
i = Future value discount rate
p = lifespan of the solar panel system
G1 = Electricity price in year 1
PS = Price of electricity for self consumption
S = Self-consumption factor
PE = Price of electricity for export
ie = Electricity price inflation
d = Solar panel degradation (annual, compounded)

See solar NPV spreadsheets to learn more about solar panel NPV calculations.

Talk to Us About Solar

Ready claim your €3,000 grant and start saving with solar today? With grants set to end soon and the opportunity to sell your surplus electricity from 2021, there has never been a better time to go solar. Don’t miss your chance!

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