If you can make it to our Gloucestershire offices on the morning of September 30^th, we are holding a FREE breakfast seminar to go over what is changing. For more information, contact our Customer Support Team on 08458 386 387.

Will my next project fall under the new Regulations?

If the planning notice for your development is submitted before the 1^st October, your site will be treated under the 2006 Regulations. This means you can have a SAP or SBEM completed under the current Regulations. This calculation will be valid even when the new Regulations kick in. The only catch is that you must start work on site within twelve months. Given the additional work you will be required to carry out under the new regulations, it makes sense it get your paperwork into the planning department as soon as you can.

Can you define ‘starting work’?

As long as you’ve broken ground on site, you can be classed as ‘starting start’… maybe this involves laying the foundations for a plot, or installing underground pipework. If you have submitted plans for a large development, you don’t need to have started work on every plot within this twelve month leniency time. The Communities for Local Government (CLG) have further guidance on this.

Will this regulation change affect my SAP and EPC ratings?

Since both the regulations and the calculations are changing, there will be some noticeable differences if you were to compare reports under both old and new regulations. It is important to remember that you won’t need to worry about retrospectively complying with the new regs – this will only apply to new sites which are lodged with planning from October onwards. The only change you may notice is that your Predicted Energy Assessment (PEA) which is issued at Design Stage may show a different reading from your Energy Performance Certificate (EPC) which is issued at As Built Stage… although we do not believe this show any substantial differences.

                Is there any free reference material about the changes to Part L?

You’ve got two options there – Energist will shortly be publishing our 32 page guide to the regulation changes which covers all areas, including L1B and commercial. This will be available to all existing customers. Alternatively, you can download the official Government legislation from the CLG, from Planning Portal and from BRE. Get in touch if you’d like a copy of our booklet, which we’re aiming to have published in time for the new regulations

                Is it true that EPC’s cannot be issued under the new legislation until the end of March?

At the moment, that is correct. This will only effect developments which are submitted to planning after October 1^st, but require their As Built certificates and EPC’s before March 27^th… so we’re only talking about the Speedy Gonzalez’s of the construction industry. It will be possible to produce the Regulation calculations under the new software, and produce the EPC under the old software during this transitional period.

Any other questions, send them over, or call Energist on 08458 386 387.

This week we’re going to look at heating, cooling and ventilation systems, and how your SAP calculation can be dramatically affected by the heating system you choose for your dwelling.

We’ve already covered fuel emission factors in a previous posting (which explains why different fuel types have such an impact on emission rates) so feel free to look back and catch up with us on that section!

As assessors, when we are completing a SAP (or SBEM for that matter), we have a list of dropdown boxes and options which we use to most accurately reflect the heating system to be used in a building.

This is fine for a standard house with a standard boiler, but when you get into the realms of a twelve bedroom mansion with a heat pump, separate boiler and immersion back-up, the SAP methodology doesn’t take account of the full picture.

SAP2005 can only deal with one main heating system per plot, one type of water heating and one type of secondary heating (which is either a fireplace, log burner or decorative fireplace. We can only enter one type of ventilation system (either standard extraction fans or a mechanical ventilation system) and there is no scope for entering comfort cooling systems. Also, currently heat pump efficiencies cannot be entered – SAP will always assume default figures which are usually higher than the actual product.

When the new Part L kicks in, SAP is being enhanced to give us (the assessors) a bigger array of options for the calculation… which will help to give more accurate figures overall.

The new SAP will allow two separate heating systems to be entered for one dwelling… if a heat pump is involved, we will be able to enter the actual efficiency (the co-efficient of performance) instead of having to make do with the default figure. Also, there will be the ability to enter two types of ventilation system – this will benefit large buildings which have heat recovery in some areas only.

Another change will be the introduction of cooling systems into SAP. If you are planning on installing a cooling system, your energy use will go up (which makes sense… the current SAP ignores them completely), but there’s a bit of a twist….

The assumed use of the cooling system will be geographically specific – in other words, SAP will predict the cooler will need more power in Cornwall compared to the Isle of Skye because of the change in climate. So the further south you go, the worse emission rates you’ll get. Interestingly the same does NOT apply to heating systems, although there are rumours this will be included in the next revision of SAP methodology.

If you’d like any more information on the changes to the Part L Building Regulations please give Energist on 08458 386 387 to see how we can help.

This week we’re going to tackle thermal bridging and thermal mass – but first we need to understand what these terms mean.

Thermal bridging occurs wherever there is a break, gap or join in the insulation of a building. So that can occur where a wall and a roof meet, at corners, around window sills and door frames and between joists. Some thermal bridges are taken into account when the U-Value is calculated (such as where timber frame cuts through the insulation), but the bits known as ‘non-repeating thermal bridges’ have to be measured differently.

Why do they have to be measured – SAP measures the heating demand of a house. The more heat that can escape from a house, the harder the heating system will need to work, so SAP includes ventilation rates (to measure purposeful air holes), U-Values (to measure thermal efficiency of the envelope) and thermal bridging values (to measure the thermal efficiency of junctions in the construction.

As assessors, we currently have default figures to use - if you build to Accredited Construction Details or a similarly approved scheme, we can use one default value. If you don’t build to a recognised quality mark, we use a worse default value. The ‘value’ in question in like a U-Value, but is measured in a linear way, not area. It is called a psi-value, the lower the better.

Under the new SAP which fires up in October, the thermal bridging will need to be measured, rather than a default figure assumed. So, providing you build to a recognised scheme, we can calculate the perimeters, corner lengths and junctions of your dwelling, and provide a far more accurate result for the SAP Calculation. A worst case default figure will still be available.

So what can you do to make this figure as favourable as possible. There’s a couple of things… you can design dwellings with fewer junctions… you don’t need to go down the route of lighthouse buildings (as they don’t have corners), but less complex shapes and designs will help. Another way of lowering your psi-value is to get hold of the psi-value for individual insulation materials (this can be near impossible to find, but we expect the industry will start publishing this information once they realize this could earn them a few extra sales.

Another area of SAP which is moving away from defaults into accurate measuring is the ‘Thermal Mass Parameter’ or ‘How well a building stores heat during the day and releases into the home at night’. When compared to masonry builds, timber houses heat up quickly but don’t store heat for as long, so you use less heat during the day, but potentially more at night.

Currently SAP does not allow you to work out your own Thermal Mass Calculation, but this too is being altered. From the test studies we have completed, timber frame houses will fair better from this change to the methodology if built with a standard specification… if you are building a house with extremely low U-Values and ventilation rates, the masonry construction will fair better.

I hope that hasn’t confused you too much – out of all the changes to SAP, this is the toughest one to explain, I’m glad we’ve got that out of the way!

If you’d like any more information on the changes to the Part L Building Regulations please give Energist a call on 08458 386 387 to see how we can help.

This week we are focusing on lighting – there’s some important changes regarding high efficiency lighting for new residential developments, and we don’t want to keep you in the dark about them (comedic symbol crash). This change does not affect commercial developments.

Under the current SAP guidance in England and Wales, any new building must have either:

-          25% of the total light fittings must be low-energy exclusive

-          OR – there must be one low-energy light fitting for every 25m2 of useful floor space – whichever figure is greater.

A couple of things to clear up – by a ‘low energy fitting’, we are referring to a light socket which will only accept fluorescent bulbs or energy-saving bulbs… standard bayonet or screw fittings do not count. Low energy is defined as anything better than 40 lumens per watt. Energy savers are around the 60-80 mark, standard tungsten and halogen bulbs are between 15 and 25.

Also, we are talking about low wattage bulbs – these are not the same as low voltage bulbs (such as halogen downlighters) which have a similar efficiency to a typical tungsten bulb.

Lighting is treated in a strange way by SAP… if you fit your house with 100% low energy fittings, you’ll get a better EPC rating, but your Design Emission Rate will stay the same. This is because the SAP methodology is currently fixed on a 30% assumption. The EPC calculation greater reflects the reality.

So, that’s where we are now… this is where we’re going under the new SAP method…

The amount of low energy lighting is increasing to 75% - so three quarters of light fittings in new buildings will need to be low energy. But this doesn’t mean you’ll need to buy expensive low-energy fittings… you’ll be able to use standard bayonet fittings throughout the house, as long as you fit 75% of them with energy saving light bulbs.

With the phasing out of traditional tungsten lamps, it’s less likely that people are going to replace energy savers with the old fashioned lights, so the idea of having ‘dedicated’ fittings is being removed.

Also, the more energy efficient bulbs you use, the better your Design Emission Rate will be and the better EPC rating you will get – the current 30% assumption in SAP is being removed.

One final note – the definition of ‘energy efficient lighting’ is being changed from 40 lumens per watt to 45… but as long as you fit the house out with A-Rated lights (as all compact fluorescents are) then you won’t have a problem here.

If you’d like any more information on the changes to the Part L Building Regulations please give us a call on 08458 386387 to see how we can help.

This week we are focusing on air testing – an area which we’ve already featured on this blog, so here’s recap:

For the last five years in England and Wales it has been advisable to have a test completed on a newly constructed building to measure how air tight it is. This is a feature of Part L and can make a large improvement to a SAP or SBEM calculation if a good air test is recorded.

The test itself has many names… ‘Air Leakage Tests’, ‘Air Permeability Assessments’, ‘Air Tightness Testing’… whatever you want to call it, it’s a measure of how much air is escaping or entering the building through the building fabric.

The air test itself isn’t changing with the new regulations, but there are some important areas you need to bear in mind.

Firstly, the amount of air tests which are required is being increased. Officially, around a quarter of all new dwellings need to be tested when built. Any development which is registered after the October 2010 date will need to comply with the new Part L, which means around half of new dwellings should be tested. It’s fair to say that, in reality, this figure will be lower and Building Control departments will retain their discretion on which plots and how many are tested.

Commercial developments remain the same. Any building with a floor area larger than 500 sqm must be tested – anything smaller can be tested in order to achieve a lower EPC rating, but this isn’t compulsory.

The other big change is the ‘confidence factor’. Currently, if a new dwelling isn’t tested, the SAP assessment is based on the value which a builder claims they can achieve. So if a builder has achieved an air test of 6 on a previous house, the SAP for the new house can also use the same figure.

From October, if any plots are not tested, the SAP calculation must be based on the average air test value on the site, plus two. So, if you have five new houses, have two tested, one result is 9.5 and the other result is 7.6, the three other plots will be assumed to have an air leakage figure = (9.5+7.6)/2 +2 = 10.55… the highest figure allowed is 10 which means your remaining plots will no longer comply with Part L.

A good rule to remember is that individual plots must achieve an air leakage rate better than 10, the site average must be better than 8.

And just to get some scope on this, Germany has a figure around 5, Scandinavian countries are around 3 and the Passivhaus standard would expect to reach around 0.5. Air tests are being phased into Scotland next year.

For more information on this, or to arrange for an air test, contact Energist UK for a free quote on 08458 386 387.

One of the areas which the encroaching alterations to Part L is going to effect is the maximum U-Values allowed on new building projects – these changes only apply to SAP in England and Wales. The maximum figures for SBEM are not changing. Renovations and extensions also have lower U-Values coming into force.

So, let’s go back to basics… What is a U-Value?

A U-Value is a way of measuring how thermally efficient a particular part of a building is – these are calculated for all heat loss elements – namely the ground floor, roofs, external walls, doors, windows and rooflights. Walls and floors adjoining unheated rooms, such as a garage or conservatory, are also included.

The U-Value is shown in W/m2K – (Watts over metres squared Kelvin) – and the lower the better (A U-Value of zero would mean that no heat loss was transferring through the element).

Under current regulations the maximum U-Value allowed for a floor is an overall average of 0.25 – on a typical house you’d expect around 100mm of mineral wool to reach this figure. Under the new regulations, this is not changing in either residential or commercial builds.

The maximum U-Value allowed for a roof is an average of 0.25 – around 200mm of mineral wool will reach a figure round that mark, although it’s usual practice to exceed this U-Value – it makes a good impact on SAP to install 300mm for not too much more cost. Come October, the average U-Value for a roof is being lowered to 0.2.

Wall U-Values are also being lowered – from 0.35 to 0.3. A standard cavity wall with full fill mineral wool should be hitting the 0.3 mark.

Currently, the average U-Value of all external doors, windows and rooflights must be no greater than 2.2 – this is being reduced to 2.0. If you’re using a good specification double glazed unit, you should find yourself around the 1.7 mark.

For SAP, There are also two NEW areas of the build which are being introduced into the calculation for the first time: Swimming pool basins must be constructed to achieve a U-Value no higher than 0.25, but the change which will effect more builders is concerning party walls.

Until now, it’s been assumed that any heat leaking through a party wall will heat the neighbouring house and vice versa, therefore having no overall effect. It’s been proven in recent years that heat escapes into party walls, and travels up the cavity into the roofspace. It is therefore advisable that, come October, all houses are constructed with an insulated party wall, sealed at the top.

A final point to note is that these changes are to be maximum values allowed – there are lots of other things going on in the new SAP calculation which will make the regulation tougher to pass, so we’ll be recommending to our clients that they aim to exceed these limiting values by as big a margin as possible.

For more information on how the regulation changes are going to effect the way you do business, contact Energist UK on 08458 386 387.

This is happening across the UK – but how much of a difference depends on where you live and what you’re building.

Let’s start with the residential market in England and Wales. Come October there’s going to be tighter U-Values limits, new U-Values which haven’t been needed before, tighter air leakage demands, more low energy lighting, better glazing specification, fewer exemptions, more attention paid to thermal bridges and thermal mass and, the big change: a 25% reduction on the Target Emission Rate.

Compare that to what’s going to be happening in the commercial sector in Part L2 for England and Wales. For SBEM calculations, most of the regulations are staying the same as before. U-Value requirements aren’t changing, heating efficiencies are staying the same… the only difference is the 25% reduction in the Target Emission Rate… but even that’s not going to be simple.

The 25% cut is going to be an average, based on the type of building being assessed – so some commercial developers will only need to reduce their emissions by 20%, others by 30%. It’s been known for some time that particular commercial buildings fair better in the SBEM calculation than others, this system is an attempt to iron out this problem, while reducing the limits on emissions at the same time.

Confused yet… let’s head over the border.

For residential developments under Section 6 in Scotland, the Target Emission Rate is going to be reduced ‘by approximately 30%’ compared to where it is now. ‘Approximately’ is how the Scottish Building Standards Agency has phrased it – they’re using the average approach (more commonly known as the aggregate TER) which is being used on commercial buildings in England and Wales. On top of this, the SBSA is also going to be offering guidance for improving the energy efficiency of existing buildings, encouraging a greater use of low carbon systems in new homes, lowering the maximum U-Values and from 2011 air leakage testing will be brought in for the first time.

Finally for now, Scottish commercial developments. Maximum U-Values are being lowered, and are going to be different to that used on the domestic side. The Target Emission Rate is going to see a flat 30% reduction (not based on an average system) and air leakage tests will be introduced in 2011. For commercial shells, the air test must meet seven with a secondary air test to be completed once the fit out stage has been completed.

Somehow, the technical team at Energist UK understand all the changes that are being introduced into Part L and Section 6 over the coming twelve months, and will be able to help you with any queries you have. Call us on 08458 386 387.