To comply with the current Building Regulations all new dwellings are required to have a SAP (TER/DER) calculation which should be carried out before construction commences.
On completion the SAP is re-calculated using the pressure test results (if applicable) and the details of the actual boiler used. SAP 2009 was introduced on the 31st October 2012.
This then provides the information which is included in the Energy Performance Certificate. This calculation introduced the TER/DER values where the TER is the Target Carbon Dioxide Emission Rate, which is calculated by the SAP software. The DER is the Dwelling Carbon Emission Rate calculated on the proposed design (which should be based on the current Part L/F of the Building Regulations).
Buildings subject to Part F 2006 and submitted approval after 30th September 2008 must have a TER/DER submitted to district councils at design stage. The DER must not exceed the calculated TER. When the building is completed the TER and DER on completion must be submitted to building control not more than 5 days after completion to demonstrate that the target has been met. The only exception to this is where the dwellings are created by the conversion of an existing building.
For new dwellings the standard U-values for the thermal elements are only a guide because there are so many other factors that affect the TER/DER figures. In most cases these U-values will have to be bettered (sometimes considerably) in order for the dwelling to achieve a TER/DER pass.
The following is a list of items which are now included in the SAP calculations and have the most effect on the TER/DER ratings:
The SAP calculation tool allows the designer a high degree of flexibility in deciding how to achieve the required energy target. However, the Approved Document does set certain limits. These include:
Ways To Reduce Bills
The cost of insulating the tank can be recovered in 1 year.
Further Ways To Reduce Bills
If you have solid walls you can either insulate them with external or internal insulation, saving you around £300 a year on your energy bills and can improve efficiency by 30%
Fitting double glazed windows will save money and cost recovered in 5 years.
You will reduce your bills and save energy by insulating your loft and there may be energy saving grants to pay for part of the costs.