sap calculations

For your own peace of mind and to satisfy Building Control these should be undertaken before you start work on site.

If you don’t have your SAP calculated professionally, you could easily add £1,000's to your construction costs through unnecessary renewables and costly heating systems.

With our experience in SAP regulations, MSBC can quickly and cost efficiently supply your SAP Assessment anywhere in England and Wales.

What is a SAP Calculation?

SAP is the Governments 'Standard Assessment Procedure' for energy rating of dwellings. (The latest version is SAP 2012 which was introduced in the Building Regulations on the 6th April 2014). It is a compulsory component in complying with the Building Regulations for new dwellings and where existing buildings are converted to dwellings.

SAP provides a simple means of reliably estimating the energy efficiency performance of dwellings. SAP ratings are expressed on a scale of 1 to 100 the higher the number the better the rating. Thus SAP is similar to the fuel consumption of a car under standard driving conditions.

How is it calculated?

SAP is calculated by a procedure contained in the Building Regulations, which predicts heating, and hot water costs. These depend on the insulation and air tightness of the house and the efficiency and control of the heating system.

SAP programs are used to enter data on the size of the house, its insulation levels, it ventilation system and its heating and hot water systems. SAP rating can then submitted for Building Regulations approval and is checked by the local Building Control department.

The first part of the SAP calculations involves calculating a Target Energy Rating (TER) for the dwelling. The next step in the SAP report process is to calculate the Dwelling Emission Rate (DER). If this is equal to or less than the TER then the SAP rating shows a pass and the SAP calculations are complete.

If the DER is not equal to or less than the TER then we will liaise with you and suggest changes that will improve the DER to ensure that the SAP calculations show a pass.

SAP 2012 also introduced Fabric Efficiency Standards which relate to the performance of the walls/floor/roof/glazing/air tightness regardless of how efficient the heating system may be and any renewable energy systems installed. Previously these elements could “under perform” provided you installed for example a Ground Source Heat Pump – this is no longer possible.

What is the difference between a SAP calculation and an Energy Performance Certificate?

The SAP calculation is the method used for demonstrating compliance with the Building Regulations whereas the Energy Performance Certificate enables the end user of the building to see how Energy Efficient the building is. The Energy Performance certificate is very easy to understand at first glance whereas the SAP Calculation contains a lot of detailed calculations and figures.

The two are linked though as the Energy Performance Certificate is calculated using the information contained within the SAP calculation.

At what point should the SAP calculation be undertaken?

It is recommended that a pdfDesign SAP calculation be carried out at early design stage to check that the building will comply with the carbon emission requirements contained within the calculation. If the requirement is not met then changes will need to be made to achieve compliance. We suggest that you undertake this at the Planning Application stage in case PV or Solar panels are required that may affect the Planning Application. The Building Regulations require the Design SAP is submitted not les than 7 days before works commence.

An ‘pdfAs Built' calculation will then be required at the end of the project. This will reflect any changes that may have been made during construction. It is important to keep us informed of any proposed changes in case they result in your building no longer complying. Unless the changes are frequent, or are dimensional changes, we do not charge for checking any proposed changes.

How much does it cost for a SAP calculation?

Most of clients are building one off houses and therefore each design is unique, for this reason we ask to see a PDF copy of the proposals and will then send you a quote specific to your project. As a guideline we tend to charge £250 (no VAT Payable) but this may be more for a complex design and less for a simple design. If the scheme involves flats or multiple plots the cost per flat/plot will be considerably less.

Our fee is all inclusive and includes the Design Calculation, As Built Calculation and Energy Performance Certificate. Should the design calculation show that the building fails to meet the Carbon Emissions Target we will advise you of the changes you should make and recalculate at no extra charge. Minor changes can also be made during construction without further charge. When comparing costs please check if other companies are including the As Built SAP and Energy Performance Certificate in the price quoted and if there is a charge should amendments be made. We do not ask for any payment until the Design SAP calculation has been completed.

What is included in our fee?

We will provide you with a Design SAP calculation based on the information you have provided which will give you the SAP rating together with the DER and TER Carbon Emission calculations. We will give you practical advice on any changes that may need to be made to achieve compliance. We will also include in the price a Predicated Energy Performance Certificate which can be used for marketing purposes during construction.

On completion of the work we will provide you with an "as built" SAP calculation and Energy Performance Certificate for display in the property. This is on the assumption that there have been no substantial changes in the design of the property during the construction work. All our information is e-mailed to you as PDF copies, hard copies can be provided but we would have to charge extra for this service. We will register the property & Energy Performance Certificate with Landmark as part of our service.

Where requested, and provided Water Recycling is not proposed, we will provide a Free pdfWater Consumption Calculation to accompany the Design SAP

What we need to calculate the SAP for you

You will need to provide us with copies of your plans, elevations and sections through the building along with the specification for the heating and hot water systems. To assist you we have a docxSAP Questionnaire for New Dwellings and a docxSAP Questionnaire for conversions which advise you of all the information we require.

what levels of insulation do I need to achieve a pass

In the Approved Documents to the Building Regulations there is a Model Design specification, which if followed should achieve a Pass on the SAP calculation.

You can view the pdfModel Design here in which we have also included suggestions on how you can meet the design requirements.

There is some flexibility as if you “under achieve” in some areas you can balance the calculation by “over achieving” in other areas. Due to the uniqueness of each house design it is difficult to predict the result until the SAP calculation has been undertaken.

My proposed house is not going to be using traditional methods of construction: Can you still complete a SAP calculation ?

Yes as long as the materials are known and we can find the thermal properties in the manufacturer’s literature. The SAP calculation though will include references to Thermal Bridging, for example the junctions between walls and floor/roof/windows. For traditional construction techniques set figures can be referred to which relate to careful detailing of the junction. As part of our service we will provide you with these details. If however non-standard construction is proposed we either have to use default values (which give “worst case scenario”) or you will have to obtain thermal bridging calculations from a specialist. Sometime the insulation manufacturer can provide these.

Accredited Construction Details give several examples of different forms of traditional construction where, if followed, will help you to achieve compliance.

Do I need a SAP calculation for an extension?

No but as a general rule you will need to keep the glazed area to less than 25% of the floor area of the extension. However if an energy analysis of the extension is undertaken the glazing can often be increased. MSBC are experienced at preparing these calculations.

Increased areas of glazing can be “traded against” improving the insulation values of the walls/floor/roof and/or undertaking “consequential improvements” to the existing house. For example changing an old boiler to a modern efficient boiler or installing double glazing.

There is a separate pdfQuestionnaire_for_overglazed_Extensions.pdf which you will need to complete along with providing copies of the Plans, Elevations and Section of the extension and the existing house.

As the method for demonstrating compliance usually involves 2 SAP calculations the fees may be a little higher for extensions but we try to keep them to £250 (no VAT Payable). If you send us copies of your plans we will be pleased to provide you with a fixed quote.

Will I need to have my house air tested?

As a general rule - Yes – the Design SAP will make an assumption on the air testing result, we usually assume a figure of 5-6 but this may be less (i.e. more air tight) in order to achieve a DER less than the TER. On completion the Building Regulations will require a pressure test and the result is entered in the As Built SAP. If the result is too high and the building no longer meets the required DER then remedial work may be required along with a re-test.

However you can chose “not to test” and a figure of 15 has to be assumed. This however means that you will need to install either very efficient heating systems and/or PV and Solar Panels. We recommend testing in every case as provided you are careful during construction you should achieve a result much better than 10.

We do not undertake air testing but will be pleased to organise a quote for this through one of our trusted suppliers.

Condensation Risk Analysis

As part of the calculation procedure we will include, at no extra cost, a “pdfcondensation risk analysis” through the various elements of construction. (This will be subject to recognized materials being used where the vapour resistivity is known).

How long will it take?

When providing a quote we will always provide you with a timescale for providing the calculation. This is generally two weeks. We can provide a quicker turn - around service if necessary. PDF copies of the calculation will be e-mailed to you as soon as the calculation is done.

SBEM Calculations

SBEM calculations required on Commercial Buildings and follow similar procedures to the SAP calculations. We do not provide SBEM calculations  but will be pleased to organise a quote for this through one of our trusted suppliers.

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