What is the SAP?

The SAP test governs the procedure by which an accredited assessor will check the carbon emissions of a building against the Government’s targets. Buildings will be given a rating of between 1 and 100, with any dwelling which scores more than 100 being classified as a net exporter of energy. Each assessment will focus on a number of factors including fabric, heating, lighting and CO2 emissions. These targets set out various limiting values of energy efficiency for heating ventilation and every part of the dwelling.

How have the rules changed?

In general targets have been ramped up over the years as Governments strove to work towards a target of zero emissions for homes by 2016. All that changed, to a certain extent, when the Conservative Government came into power in 2010. They froze those targets which inevitably meant the UK missed that ambitious goal of zero emissions from homes by 2016. Even so, this is where the trend is heading. One day it will come into force as it has already has in London and, where the capital leads, everywhere else tends to follow.

What will cause a fail?

Meeting these targets is vital, but any one of several factors could cause a failure. The most common causes of failure tend to be:

• High elemental U-Values: These are the values which demonstrate the energy efficiency of that element. If they are too high it can lead to failure of the assessment.
• Failing to deal with thermal bridges: Failure can be caused by problems at junctions within the building such as window jams or sills and tightness.
• Poor heating and ventilation strategy: Expecting to get away with electrical heating when realistically this will not achieve what you need to.

Addressing these points will give you the best possible chance of securing a pass. 

What do you use to ensure they pass their assessments?

Tests focus on U-values – which is the amount of energy transferred between materials. Each element has limiting values which are pretty high so beating them is reasonably straightforward, but you have to go far beyond if you are to pass. Even so, it is possible to go too far. If this happens, costs can rise quite quickly. Walls become thicker to accommodate larger quantities of insulation and, before long, you will find you’re getting very little incremental value for your efforts. A key element, therefore, is to ensure walls and ceilings have the right type of insulation.

The next is to ensure windows in highly glazed developments are energy efficient enough.These days it is relatively straightforward to bring efficiencies down to a U-Value of 1.0. This might involve laying down window specifications for the buildings and this is something that we, at Carbon Green can do for our clients. We recognise that people need to pass the SAP assessment, but equally, budgets are normally tight. The challenge is to find solutions which work within the resources available.

Heating and ventilation

One of the key battlegrounds is heating and ventilation and this is where owners often make mistakes. Many believe that you can simply put a reasonably efficient electric heater on the wall, but more often than not that will not be the case. Although electric heaters have become much more efficient over the years, they remain extremely expensive from a CO2 perspective. It is still highly problematic and can make it difficult to pass the assessment.

Sometimes, though, it’s unavoidable. Perhaps there is no gas in the building and you can’t find a way to use alternative strategies. When that happens, we have to work around it and find ways to offset the impact of electrical heating.

We might focus on thermal bridging and accredited or enhanced construction details to ensure there is no energy loss from those junctions, sills, lintels and jams. The corners, and floors of buildings will need to be designed well to ensure there is minimal heat loss and this will have a significant impact on the SAP assessment.

Putting it into practice

In one recent project, we were asked to work on a site comprising four blocks of six flats. The builder insisted we had to use electric heating because the site lacked gas and it was difficult bringing gas to that location. The pipework which would have been needed to get alternative sources to the building also made it impractical.

So, with electrical heating a given, we focused on getting good elemental values in the build up of the walls and ceilings. They were not as good as they could have been but this was because they used inferior insulation. By replacing it with a superior insulation which gave better values for the same thickness, we managed to improve the energy efficiency of the building. Equally, the builder hadn’t considered using accredited construction details for his junctions which we encouraged him to do.

Next, we had to think about how we would address the heating and ventilation strategy. Ventilation wasn’t too difficult to deal with because there were windows on either side, which gave cross ventilation and meant there was no need for mechanical ventilation.

Heating was a different matter. In the end we looked at high heat retention storage heaters. Many people view Storage heaters as being highly inefficient and ineffective, but technology has come a long way. These are now much more energy efficient than they used to be and deliver more value to the customer.

All these measures gave us a pass across all of the flats on block compliance and we didn’t need any renewables to compensate so we passed both the target for CO2 and fabric efficiency.

This example shows why sometimes, passing the SAP assessment needs a little expertise in the dark arts. It’s not a case of bending the rules but understanding how each component of the building works, so if we’re constrained in one area, we can adjust to another. That is the key to solving the challenges of SAP. 

What is the SAP?

The SAP test governs the procedure by which an accredited assessor will check the carbon emissions of a building against the Government’s targets. Buildings will be given a rating of between 1 and 100, with any dwelling which scores more than 100 being classified as a net exporter of energy. Each assessment will focus on a number of factors including fabric, heating, lighting and CO2 emissions. These targets set out various limiting values of energy efficiency for heating ventilation and every part of the dwelling.

How have the rules changed?

In general targets have been ramped up over the years as Governments strove to work towards a target of zero emissions for homes by 2016. All that changed, to a certain extent, when the Conservative Government came into power in 2010. They froze those targets which inevitably meant the UK missed that ambitious goal of zero emissions from homes by 2016. Even so, this is where the trend is heading. One day it will come into force as it has already has in London and, where the capital leads, everywhere else tends to follow.

What will cause a fail?

Meeting these targets is vital, but any one of several factors could cause a failure. The most common causes of failure tend to be:

• High elemental U-Values: These are the values which demonstrate the energy efficiency of that element. If they are too high it can lead to failure of the assessment.
• Failing to deal with thermal bridges: Failure can be caused by problems at junctions within the building such as window jams or sills and tightness.
• Poor heating and ventilation strategy: Expecting to get away with electrical heating when realistically this will not achieve what you need to.

Addressing these points will give you the best possible chance of securing a pass. 

What do you use to ensure they pass their assessments?

Tests focus on U-values – which is the amount of energy transferred between materials. Each element has limiting values which are pretty high so beating them is reasonably straightforward, but you have to go far beyond if you are to pass. Even so, it is possible to go too far. If this happens, costs can rise quite quickly. Walls become thicker to accommodate larger quantities of insulation and, before long, you will find you’re getting very little incremental value for your efforts. A key element, therefore, is to ensure walls and ceilings have the right type of insulation.

The next is to ensure windows in highly glazed developments are energy efficient enough.These days it is relatively straightforward to bring efficiencies down to a U-Value of 1.0. This might involve laying down window specifications for the buildings and this is something that we, at Carbon Green can do for our clients. We recognise that people need to pass the SAP assessment, but equally, budgets are normally tight. The challenge is to find solutions which work within the resources available.

Heating and ventilation

One of the key battlegrounds is heating and ventilation and this is where owners often make mistakes. Many believe that you can simply put a reasonably efficient electric heater on the wall, but more often than not that will not be the case. Although electric heaters have become much more efficient over the years, they remain extremely expensive from a CO2 perspective. It is still highly problematic and can make it difficult to pass the assessment.

Sometimes, though, it’s unavoidable. Perhaps there is no gas in the building and you can’t find a way to use alternative strategies. When that happens, we have to work around it and find ways to offset the impact of electrical heating.

We might focus on thermal bridging and accredited or enhanced construction details to ensure there is no energy loss from those junctions, sills, lintels and jams. The corners, and floors of buildings will need to be designed well to ensure there is minimal heat loss and this will have a significant impact on the SAP assessment.

Putting it into practice

In one recent project, we were asked to work on a site comprising four blocks of six flats. The builder insisted we had to use electric heating because the site lacked gas and it was difficult bringing gas to that location. The pipework which would have been needed to get alternative sources to the building also made it impractical.

So, with electrical heating a given, we focused on getting good elemental values in the build up of the walls and ceilings. They were not as good as they could have been but this was because they used inferior insulation. By replacing it with a superior insulation which gave better values for the same thickness, we managed to improve the energy efficiency of the building. Equally, the builder hadn’t considered using accredited construction details for his junctions which we encouraged him to do.

Next, we had to think about how we would address the heating and ventilation strategy. Ventilation wasn’t too difficult to deal with because there were windows on either side, which gave cross ventilation and meant there was no need for mechanical ventilation.

Heating was a different matter. In the end we looked at high heat retention storage heaters. Many people view Storage heaters as being highly inefficient and ineffective, but technology has come a long way. These are now much more energy efficient than they used to be and deliver more value to the customer.

All these measures gave us a pass across all of the flats on block compliance and we didn’t need any renewables to compensate so we passed both the target for CO2 and fabric efficiency.

This example shows why sometimes, passing the SAP assessment needs a little expertise in the dark arts. It’s not a case of bending the rules but understanding how each component of the building works, so if we’re constrained in one area, we can adjust to another. That is the key to solving the challenges of SAP.