In addition to the energy savings recognised within SAP, the GasSaver and SuperFlow systems offer many additional benefits. These systems represent the most sensible and cost effective energy saving measures available.
Cost & Payback Period
The GasSaver is available for around £545 (volume discounts available). An analysis of field trial data gathered by Antler Homes calculated total annual savings of £147 giving a payback period of under 4 years. (Fuel costs of 2.941p per KWh - British Gas direct debit rate as of Sept 2006. Savings include gas and water savings.)
SuperFlow systems are available from around £1800 including boiler & GasSaver.
Direct Energy Savings
For the purposes of SAP 2005, the energy savings of the GasSaver and SuperFlow systems are calculated using the Appendix Q route. The exact energy savings figures take into account a number of factors from the main SAP worksheet but are mainly influenced by the floor area (used to determine DHW energy usage) and space heating requirement of a given dwelling. See our guide to completing Appendix Q. In SAP 2009, savings for FGHRSs will be incorporated into the main body of SAP.
For a modern house, typical energy savings figures are shown in the table below. In older houses with higher space heating requirements, the savings are much greater.
|Annual Space Heating Requirement
|Typical Annual Energy Savings (KWh/year)
|SuperFlow 50 & PV||632
Indirect Energy Savings
A combi-boiler system eliminates the standing losses from large cylinders and primary pipe-work associated with cylinder based systems. Whilst combi-boilers are deemed to have an annual 600 KWh loss within SAP, this is usually less than the losses associated with traditional cylinder based systems. The net result is that using a GasSaver equipped boiler yields energy savings in excess of the figures in the table above when compared with a cylinder based system.
With a combi based system, you only pay to heat the hot water that you use. A recent field trial performed by Gastec on behalf of the EST found that for cylinder based systems as little as 50% of the energy used to heat the cylinder was actually used at the tap. (In-situ monitoring of efficiencies of condensing boilers and use of secondary heating, June 2009 - Page 30).
- Zero Maintenance
- Low cost
- Saves water as well as gas
- Easy to install - new build & retrofit
- No user interaction required
- Improved DHW performance
- Much smaller footprint than traditional cylinder based systems