Information on payback periods for some technologies under the CERT regime is shown in the following table. Savings figures are approximate and are based on a typical three-bed semi-detached home. Installed costs are not the full economic cost of the work but incorporate a level of subsidy provided by suppliers under the CERT programme.
|Measure||Annual saving (£/yr)||Installed cost||Installed payback||Emissions savings (kgCO2/yr)|
|Loft Insulation (0-270mm)||Around £150||Around £250||~ 2 yrs||750|
|Loft Insulation (50-270mm)||Around £45||Around £250||~ 6 yrs||200|
|Cavity Wall Insulation||Around £115||Around £250||~ 2 yrs||630|
|Internal wall insulation||Around £380||£5,500 - £8,500||~ 20 yrs||2100|
|External wall insulation||Around £400||£10,500 - £14,500||~ 25 yrs||2200|
|Draught proofing||Around £25||Around £200||~ 8 yrs||130|
|Floor insulation||Around £60||Around £500||~ 8 yrs||320|
|Hot water tank jacket||Around £35||Around £50||~ 1 yrs||200|
|Gas Boiler (replacing G rated with A rated)||Around £190||Around £2500||~ 13 yrs||1000|
Information available at:
The actual payback period is a function of the cost of the technology, the cost of installation, the actual number of running hours per year and the cost of the fuel saved per year. As these variables are influenced by commercial considerations, which are different for each technology, and as each installation is bespoke, the actual payback period will vary considerably.
Circulator pumps are consumers of energy, though some operate more efficiently than others, particularly those that can modulate their output to match the load. We do not have the information on the payback periods for circulator pumps.