We’re now saving well over over two and half grand a year, and will have made our money back in just a few years.
Last year our energy costs looked like this:
Energy Costs 2015
Gas £10 + £80 standing charge = £90 Electricity £400 + £60 standing charge = £460 Solar PV income -£475 Solar Thermal income -£250 Air Source Heat Pump income -£1,000 Total £1,175 income
Energy Costs Before £1,500 a year Typical Energy Costs After, until 2021 £1,250 income Saving £2,750
This shows that in summer when the days are long and bright we’re paid more for our solar PV (the yellow line is below zero), but in winter with the heating on, we buy more from the grid.
In Spring 2014 the Renewable Heat Incentive (RHI) began, and we started getting paid for the renewable heat generated by our heat pump and solar thermal. It is difficult to meter the amount of heat generated so they pay a fixed rate, which is why the light green lines are straight.
We now only use gas for cooking, so if we replace our cooker with an induction hob/electric oven we could completely disconnect the gas and save the standing charge.
A quick tot up of the main improvements gives us:
LED Lighting £150 Loft Insulation £0 Cavity Wall Insulation £315 External Wall Insulation £1,240 Internal Wall Insulation £4,000 Under Floor Insulation £200 Doors £2,300 Extractor Fan with Heat Recovery £265 Air Source Heat Pump £11,500 Solar PV £8,000 Solar Thermal £4,200 Total £32,000
Increase in House Value
Improving the efficiency of your home significantly adds to it value.
A serious piece of research by DECC looked at the Energy Performance Certificate (EPC) Ratings of 300,000 homes across England, and sale prices. It found energy saving improvements added an average of 14% to the sale price – but up to a whopping 38% in some parts of England.
For our house, based on these figures, we might expect a 20% increase in value – £24,000.
Bills Before £1,500 a year Investment £32,000 Bills after, 2014-2021
includes income from the RHI and FiT
-£1,250 Bills 2021-2023
£0 Payback Time 15 years
I think that payback time is pretty good.
However, if we account for the increase in house value, then the result becomes dramatic:
Investment £32,000 Increase in House Value £24,000 Net Investment £8,000 Payback Time 3 years