SAP Calculations (Standard Assessment Procedure) are essential to your building project
SAP Calculations (Standard Assessment Procedure) are essential to your building project
However confusing they might appear, SAP Calculations are a core element in the design of any residential scheme, and an essential part of existing Building Regulations. SAP ratings have been mandatory for new homes (Part L) since 1995, and or this reason, most developers have a working knowledge of their content.
First time builders — developers and self-builders — are sometimes challenged by the process of building and planning.
The role of SAP calculations is threefold:
A slightly different SAP calculation may also be required when building an extension or carrying out a conversion. If you are building in Scotland, bear in mind that different requirements apply, so please make additional checks.
SAP is an abbreviation for ‘Standard Assessment Procedure.’ This is the sole, government-approved system for determining a new home’s energy rating. Companies approved to make SAP assessments have to be accredited and registered with a certification body.
SAP Ratings make for easy comparison between homes, allowing potential buyers to choose between dwellings having different SAP scores. A SAP scale runs from 1 and 100, where 100 represents no energy costs at all. Dwellings can have ratings over 100 (This would mean they are capable of exporting surplus energy). The higher a dwelling’s SAP rating, the lower the fuel bills and, significantly in this era of climate change, the lower the emissions of carbon dioxide.
Factors taken into account when calculating energy costs include:
Calculations do not include the energy consumption of appliances (including cooking appliances).
No one is entitled to let or even market property for intended sale unless the relevant builder can demonstrate conforming SAP calculations.
SAP matters for other reasons too. A SAP assessor can play an active role in assisting designers and architects to create the optimum energy profile of new builds – minimising energy use and pushing down carbon emissions.
Accurate SAP certification reveals differences in the relative effectiveness of various types of construction and home heating models, which in turn informs delivery to the end-user.
A further critical point concerns the sharing of SAP data. SAP ratings lay bare the energy performance of relative dwellings and are made freely available through the EPC document.
To ‘pass’ a builder must:
Crucial emissions targets are calculated through what are known as DER/TER numbers. Calculations of CO2 emission levels result from a comparison of the Target Emission Rate (TER) and a prediction of the Dwelling Emission Rate (DER). A target rate can be determined following the application of baseline measurements to a representation of a roughly similar house.
Councils increasingly employ CO2 calculations to meet their own sustainability targets and to further energy policy.
A requirement to assess the Fabric Energy Efficiency (FEE) of all new homes was brought in in England for dwellings built post-April 2014.
FEE does not measure carbon. It records energy requirements in kilowatt-hours per square metre per annum. How effectively dwellings retain heat closely relates to its CO2 emissions — a separate measure subject to compli-ance testing.
Fabric Energy Efficiency is assessed using DFEE/TFEE figures, with targets set in SAP using reference values relating to property size.
It is essential that all technical specifications from which SAP inspectors derive their measurements are comprehensively detailed, highly accurate and professionally determined. Drawings should be to scale and depict all elevations. From the technical specifications of such elements as ventilation, heating and AC systems, assessors construct models of homes using SAP computer applications. Manufacturers’ databases are then accessed and specific product details incorporated.
Every thermal detail of the building’s fabric is also added as are the details of any renewable or cooling technology.
A finished set of SAP calculations constitutes a comprehensive, fully-accessible database of building knowledge on everything from heat loss, to fluctuations in seasonal demand.
Nowadays, starting work before you have a SAP design is challenging. Whereas in the past, architects and developers all but ignored SAP, changes to SAP in 2005, 2009 and 2014, now ensure that SAP regulatory compliance is much tougher to attain.
Unsurprisingly, given the current climate crisis, and resultant EU and UK environmental policies, control of CO2 emission targets have tightened enormously. A typical new build designed just 5 years ago has a good chance of failing today’s regulations.
One of the most common FAQs on this subject is, ‘Why do some builds fail and others pass?’ There’s no easy answer, but a variety of factors can contribute to a rejection: Boiler size, for example. Or a non-compliant wall junction. Even the thickness of floor insulation on a floor, or the direction in which a house points!
Some factors lie beyond client control – if a dwelling has no connection to mains gas; for example, the owners might have to use oil or gas. Fossil fuels cost more and generate significant CO2 emissions, and because Target Emission Rates are based on mains gas, you may lose out.
As highly experienced players in the field of SAP calculation (We make SAP calculations every day — encompassing anything from one-off self-builds to multi-story tower blocks), we are experienced enough to recognise what works in the real world. And arguably more importantly, what doesn’t work at all.
Setting aside the weighty considerations of climate change, and agreeing that our goal is not to create the zero-carbon home, we can identify the following rules of thumb:
1. We believe that minimum values represent target to be smashed.
Provided the dwelling has well-insulated fabric, renewable technologies will not be needed to see you through, so feel free to incorporate as much floor, roof and wall insulation as you can.
2. A significant amount of heat is lost through windows and doors
Watch the value of ‘u’ on any openings you specify, lowering them as much as you can. Aim for 1.4 W/m2K or under.
3. It’s the controls — don’t blame the boiler
Zonal heating and boiler load compensators often impact significantly more on the SAP rating than primary systems.
4. Make it airtight
Every new build requires Air Permeability Tests on completion, with the final figure input to the SAP calculations. The envelope should be sealed and execute a pre-test check.
5. Thermal bridging is important
Thermal bridging is heat loss that leaks out through areas where external walls meet. Schemes like Accredited Construction Details (ACD’s) avoids the need for default figures. See our guide to thermal bridging.
The best advice we can offer, though, is to start early. Late submission of dwelling plans curtails our ability to alter the energy performance of a dwelling. The danger in being tardy with plans is that remedial action necessary to pass the regulations might end up involving the installation of less than suitable, costly technologies to ensure a ‘pass.’
The remedy is to engage a SAP assessor early – ideally, before planning has even been submitted, and certainly well before building regs applications.
The length of time it takes to get your application passed depends on your construction timeline. Briary Energy has a target for completion of between 5–10 working days after submission of a request.
The bottom line? It’s illegal to sell or even rent a property that doesn’t have a valid EPC. It is, therefore, essential that your building passes its SAP and that all SAP calculations are complete before starting any building work. Should the dwelling fall short of building regulation standards, our SAP specialists can offer advice on how to improve.
The longer you leave things, the more you restrict your ability to make changes. And the greater the risk of higher bills, as the range of changes available becomes more limited. We aim to provide comprehensive support and guidance throughout the entire SAP process. Though many companies provide calculations only, we offer customers consultancy services to ensure they have everything they need to pass.
A SAP rating is the measurement needed to produce a Predicted Energy Assessment and On Construction Energy Performance Certificate. Building Regulations allow a SAP calculation and a predicted EPC to be submitted for new buildings before construction begins.
SAP is ' Standard Assessment Procedure. ' It's the only legal, government-approved method for determining a new home's energy rating SAP assessors must be accredited with a certification body.
SAP calculations are often required for extensions, especially if your proposal includes large glazing areas. Building Regulations Part L1b requires new glazing areas to account for no more than 25 percent of new floor area.
Our SAP Calculations for New Builds and Conversions cost from £50+VAT for one unit and from £30+VAT for each multiple units on one site. Our price includes limitless advice on how best to get the project to meet Part L of building regulations.
Part L is a building regulation that covers new construction schemes, which restricts the use of a dwelling or all other buildings in England. This sets new and existing buildings ' energy efficiency and carbon emissions requirements.
“Thank you for all of your hard work for this scheme, never said no, never delayed always received on the day of EPC request or the next working day, just totally brilliant at all times”
Design stage – where you will need to make a submission to Building Control before any work begins
Built stage – once the dwelling has been completed and established
The two submissions of SAP Calculations are used by Building Control to check your compliance in accordance to the related targets.
There must be evidence when it comes to your product specification – evidence that the design specification has been met. When you reach the ‘As Built’ stage of SAP Calculations, you will also need an EPC for the dwelling as well.
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