FAQ's

How can a SAP calculation help me value engineer my project?

SAP is a compliance tool. It works out the carbon dioxide usage of a proposed building and compares it to the carbon dioxide usage of building with fixed characteristics. By ‘ringing the changes’ of the proposed building, e.g. changing the insulation, the means of heating, introducing Low Carbon Technology the cost of a compliant building can often be lowered.

How will I know which insulation type and thickness I need to comply?

This is solely dependent upon what U value is required for each building element to achieve a SAP pass for a given building. Until the SAP calculation is completed the U values are unknown, making it impossible to advise on insulation. Once the U values are known and have been calculated, we can offer guidance on suitable products to achieve the required performance for compliance.

Are there any new products or systems that could make compliance easier?

The simple answer is yes. Our on-going research and development has resulted in a number of innovative solutions which provide the required performance with ease, along with other benefits. Examples are – Insulslab, a complete foundation to finished floor, offering significant cost savings over traditional methods and typical U values of 0.10-0.12 W/m2K.

What is the difference between a psi value and a U value?

A psi value indicates the loss of heat at a junction between two planes, such as a wall and a floor and a U value indicates the loss of heat at a plane surface such as a wall.

Is there a cost difference between CfSH level 6 and Passivehus standard?

Rough generalization building passive houses costs a few percent more than level 6 buildings. Passive houses do, however, make for a lower overall cost after only a few years, due to the reduced expenditure on energy. However this will depend on the specific project.

Does SIG360 offer 'supply and fix'?

For the majority of fabric insulation it does not, however with certain renewable items it does. For example Heat Pumps and PV cells. This is because for the homeowner to be able to claim government financial incentives (such as Feed in Tariffs) the installer needs to belong to the Microgeneration Certification Scheme.

During construction can I change the fabric specification after the ‘as designed’ SAP has been calculated?

Once construction has begun, changes in product specification are often false economy. Even minor alterations can have a detrimental effect on overall building performance within the SAP. This may result in an “as built” SAP failure upon completion, along with the associated costs of remedial measures. At design stage, we will calculate the most cost-effective means of compliance overall, taking a holistic view of your specific project. The resulting specification needs to be closely adhered to in order to realise overall savings and eliminate risk.

Can I trade off fabric performance against renewables or vice versa?

Fabric must always come first but renewables can play an important role. The SAP process is a delicate balancing act with almost endless permutations. Therefore, striking the right balance between fabric and renewables yet doing so cost effectively can be a complex. Our expertise in this area enables us to quickly determine the right choice at the right cost to your specific requirements.

I can’t find the answer to my question?

If you need further guidance, please contact us.