SAP Calculations – Why You Need Them If You Are Planning a Conservatory

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Are you building or planning to build a conservatory? Have you been asked by your local Building Control officer to submit a copy of SAP Calculations? There is a reason for that and this article explains why.

The Standard Assessment Procedure

In the UK, the energy efficiency of exiting dwellings is produced using a method called Standard Assessment Procedure (SAP). This methodology serves two primary purposes:

1. Ensures that new homes comply with Part L (Conservation of fuel and power) of the Building Regulations, and
2. Generates the Energy Performance Certificates (EPCs). The EPC informs potential buyers, or tenants of the energy efficiency of the building and annual energy costs. Get more info about EPCs on Gas Safety Certs. 

Whether you are considering purchasing a new property, or renovating an existing one, it is essential to understand that any construction work must adhere to the regulations outlined by your local Building Control office. These rules must be followed to ensure that the building work meets the required standards and energy efficiency criteria set by the government. Energy Performance Certificates (EPCs) inform potential buyers or tenants of a building’s energy efficiency and annual energy costs. 

SAP Calculations for conservatories

Building Regulations stipulate that the area of new glazing in extensions and conservatories should not surpass 25% of the floor space, as windows tend to result in more heat loss compared to walls and roofs, impacting the overall energy efficiency of the structure.

Furthermore, the regulations highlight the significance of controlling solar heat gain to prevent excessive internal temperatures. It recommends a range of strategies such as managing window dimensions, orientation, shading, ventilation and thermal mass to regulate the indoor climate effectively.

Alex Papaconstantinou is a senior SAP Assessor at epc4less.com, a nationwide provider of SAP Calculations in the building industry. He explains that if you are concerned that your proposed conservatory may not meet the current building requirements then you should get a SAP Assessor involved at the design stage. Once a conservatory is built it may be too late, or too costly, to make amendments in order to achieve compliance with building regulations.

Why do you need SAP calculations for a conservatory?

When the proposed conservatory is separated from the main dwelling by external quality doors, then it is very likely that Building Control will not request a SAP Assessment to be carried out.

If the proposed conservatory is linked to the main dwelling, in other words there are no separating doors between the conservatory and the main dwelling, then Building Control will request SAP Calculations to be carried out.

Building Control will want to see that any alteration to the existing dwelling will not decrease the energy efficiency of the current building. The rules dictate that any plans to alter any dwelling should increase the dwelling’s energy rating performance, and not decrease it.

How do SAP Calculations for conservatories work?

There are usually three steps in the process:

1. Firstly, the SAP Assessor will prepare an assessment of the existing dwelling – without the conservatory. SAP, the tool used for producing the energy rating metrics, will produce the Dwelling’s Fabric Energy Efficiency (DFEE) and the Dwelling Energy Rating (DER).
2. Secondly, the SAP Assessor will prepare an assessment of the existing dwelling with the conservatory. The new DFEE and DER figures in the proposed alteration should be better than those of the existing dwelling.
3. Finally, if the new metrics are worse than the existing ones, then the Building Control officer may request that the proposed design comes together with changes to the existing dwelling. The SAP Assessor will estimate these changes, which may include the installation of a more efficient heating system, or the installation of photovoltaic panels. The purpose of these improvement to the existing dwelling will be to counteract the negative impact of the proposed conservatory.

SAP calculations adopt a comprehensive approach to compliance by examining the entire building to ensure precise outcomes and compliance with regulations. This involves assessing insulation levels, heating systems such as upgraded boilers, and other variables to counterbalance CO2 emissions stemming from heat loss in glazed extensions or conservatories.