SIGA

Future Homes – a recipe for success?

Regulations are changing, and you have a chance to have your say. We summarise the main proposals to change UK regulations for new build domestic. This will affect how new homes look, what they are made from and how they are heated and ventilated.

This is your chance to influence the direction of the building sector for the next 30 years

The UK must get to net zero greenhouse gas emission by 2050. Major changes in the regulation of the energy and comfort of new homes are coming. For all of us this will affect the way we currently work.

A previous government ‘cut the green crap’. Since then we have had a generation of deregulation of the domestic sector. Despite, or because of this the necessary mass decarbonisation is well behind programme. For example compare the sector to energy.

This is construction’s chance to shine, if we do it right. Or to put it another way, this is our last chance to avert a global catastrophe.

What are they asking us to comment on? What changes are afoot?

The Future homes standard 2025

The ‘Future Homes Standard’ is a (surely) timeless way to describe the regulation. It seeks a 70-80% reduction in emissions. As they are not implementing the changes until 2025, there’s an interim hike of 20-30% five years previous.

The regulators are asking us to comment on how far and how quickly the carbon reductions should be made. In addition, we’re invited to comment on the weighting that should be given to certain technologies such as communal heating or heat pumps.

  • Do you think the focus should be on carbon emissions, on fabric efficiency, affordability, primary energy? Or a combination of these metrics?
  • Building regulation incremental improvements haven’t been successful in reducing carbon emissions. Passivhaus is a proven way to improve as-built performance. The Passivhaus Trust is pushing for it to be mainstream by 2030. Do you think new homes should be Passivhaus, say, with direct electric heating? Alternatively, should communal systems provide heat from undefined low carbon sources, with less efficient building fabric?
  • Do you think the targets should be tougher, or do you think the process of enforcement is not strong enough? The culture in our industry is currently ‘design for compliance’; do you think this should be changed to ‘design for performance’?

If you have views, it’s time to make yourself heard

The paper signposts other big changes, such as removal of fuel factors. This will remove the incentives currently given to fossil fuels.

The announcement concedes that the changes will increase the cost of building a new home. The increase is up to £5k. It works out to a heady 0.3% annual increase in costs since 2013.

The standard proposes to remove powers from local authorities to set their own targets more stringent than national building regulations. Presumably, this is to ease the impact on large housebuilders and simplify approaches nationally. Local Authorities retain control over training and resourcing of Approved Inspectors.

Do you agree that councils should lose flexibility to push harder in certain aspects of energy policy? For example, if they feel that it isn’t fit for purpose. Is a one-size-fits-all approach for the whole country the best way? So long, localism.

Part L; Conservation of energy; New Dwellings; 2020

A new Primary Energy Target replaces the Fabric Energy Efficiency (FEEs) target. A primary energy target should ensure more sensible regulation of homes heated with decarbonised electricity. But, dropping the FEES is a backward step, as we address below.

Part L will continue to use carbon dioxide as an additional target – with either 20% or 31% reduction. In addition a household affordability standard is proposed. This makes allowances for costs savings, e.g. via electric battery storage. Battery storage is sure to become much more common in the near future. It feels under-represented in the proposals.

Crucially, the notional building is still used as a comparative tool to set the target. Critics of the regulation feel this is an unnecessary abstraction that confuses clients and creates inconsistency.

More importantly though, the notional building method means that there is no incentive for an efficient building form. Buildings shaped like a game of Jenga, or Tetris incur an obvious energy & comfort cost. As the notional building shape matches the actual, there is no penalty for this. Explanation of the notional building in regulation . The FEES (Fabric Energy Efficiency Standard) used to be the backstop for this, but that is now been omitted.

The documentation is being simplified. Documents L1A, L1B and Domestic Building Services Compliance Guide will all be wrapped up into one document Part L1; Dwellings.

SAP 10

The regulators have retired the Approved & Enhanced Construction Details for thermal bridging. They’re replaced by much more bespoke modelling of the details. Or in reality, credulous or over-worked Building Control professionals are likely to continue to simply sign off thermal bridging.

This is a very tricky area to get right. A more robust approach starts with changing the measurement protocol to external measurements. This would include far more of the heat loss in the wall heat loss calculation.

Heat networks are encouraged, because the country has already made significant investment in them. In certain specific circumstances they are the right solution.

The performance of heat networks is up-voted by a blanket ‘technology factor’ (not a fudge factor). This is applied to all networks, no matter the application. The consultation documents mention, but do not specify, what the technology factor will be. The default efficiencies presented are hopeful (60W heat exchange loss per dwelling).

Unfortunately there is no mention of mandatory performance testing of these extensive & highly bespoke systems. How heat networks are currently, regulated and how to improve that.

Part F; Ventilation 2020

SIGA focuses on airtightness, but that is one small part of achieving a healthy home. You might have heard of this mantra in the building science world:

“Build tight; Ventilate right”

i.e. we should be making airtight buildings, but you fundamentally need proper ventilation to make it work. This is so important, that perhaps it should be tattooed on the arm of every builder, and every civil servant at the MHCLG responsible for regulation.

Build tight- Ventilate right. It’s kind of important to do both.
https://makesweet.com/my/shoulder-tattoo

For buildings with poor airtightness, uncontrolled air infiltration passes through the building fabric. Part F relies on this for fresh air supply & extraction. Do you agree that this is a suitable way keep the newest homes in the land healthy?

The consultation reviews the minimum ventilation rates, based on some very thorough research. The guidance is being simplified. Simplification is no bad thing in itself, so long as it is not simply deregulation. You might agree that deregulation of a sector which has been shown to cause inefficiency and ill-health would be reckless.

Contractors will be required to provide more information to the resident on how their systems work,. This would be a good thing, if it were scientific. Refer to Appendix C of the proposed document for this proforma.

Unfortunately, the process is mostly a tick box exercise. The proposals do not include an enhancement of the performance testing regime. Here is an example of a proposed yes/no test for quality inspection:

“For ducted systems, has the ductwork been installed so that air resistance and leakage is kept to a minimum?” 

Do you agree this is a powerful test of compliance. Or, or do you think this becomes meaningless without specific targets, and without performance-based compliance?

Airtightness of new Dwellings

The main headline here is that from now on single sample testing of units will not be allowed.

We must now test every single new build home for airtightness, even on smaller sites.

SIGA welcome this development. Airtightness is an excellent measure of building quality & comfort. Performing an air test is a proven method to identify possible future building damages. It results in a building shell of a higher quality. The regulators have improved the minimum (worse) standard for airtightness from 10 to 8 m3/hr/m2 @50Pa.

This target is still shockingly poor to some.

The proposed UK housing standards (to 2050) are at least twice as leaky as current standards in neighbouring countries with similar climates such as Ireland, France, Holland, & Germany.

For the proposed UK Part F 2020; if the home is naturally vented, i.e. with trickle vents, the lowest airtightness that can be entered into SAP will now be 3m3/m2.h. This closes a previous loophole in the SAP method.

As an alternative to blower door testing, the ‘Pulse test’ will be permitted for AT buildings>1.5 m3/hr/m2 @50Pa.  They are reviewing the testing method to make it more consistent. It will available here from mid-October. Do offer comment on this if you have relevant experience.

Voluntary professional bodies such as ATTMA or IATS do the quality auditing of UK airtightness testing. The air test is very important, because currently its the sole as-built test of building quality. Should the auditing be replaced by, or run in parallel with, a separate government body?

Performance testing is, of course, better than no testing at all. But in the absence of oversight, it can have unintended consequences, as we’ve seen in the diesel emissions scandal in the car industry.

Improving compliance to reduce the performance gap

Unless it is enforced, a performance standard isn’t worth the pdf it’s written on. Do you agree that enforcement has always been the weakest part of the regulations?

Although the consultation does address quality control specifically, there is very little radical change here. Read the tips here on improving the airtightness of the following important areas in Annex C (page 72) of “The Future Homes Standard”. The document highlights the key areas for attention:

  • Incoming services
  • Structure
  • Around openings such as windows
  • Internal services

What is missing is graphical or video guidance, or guidance on what to do at each RIBA work stage. Here are some short practical guidance videos from SIGA, by way of example:

The presentation of as-built reports has been unified. You must now include photographic evidence with the reports,. You must include a home user guide to educate the occupier in how to use their new home.

Lord Debden has witheringly described the UK’s response to climate change as ‘Dad’s Army’. Is this more of the same?  Are they tweaking with a formula that’s been proven not to work? Is this the government just ‘looking busy’?

Here are some obvious omissions. While some of these may be outside the scope of this consultation, they are fundamental to the prospects of it:

  • As-built testing or direct feedback of failures (with exception of airtightness testing)
  • Random spot checks of results (ditto)
  • Mandatory publication in a public register
  • Leading from the front. For example, public-funded schemes to push further
  • Coordination with the supply chain; to explore the necessary materials/components
  • Coordination with supply chain; to recruit & train the necessary trades & skills
  • An essential piece of the UK energy puzzle is heat/electrical storage, to limit peak time loads. This is not addressed. 

Get involved. Have your say

In summary, its full steam ahead along the same lines we’ve always had; set an aspirational target but don’t require it to be tested in practice (mostly).

A lot of the specifications are moving towards the Passivhaus approach. What is missing is significant improvements in the process & enforcement.

As they say, you can put sugar, butter, eggs and flour in a bowl. Unless you follow the recipe, you won’t make a cake.

The process is just as important as the ingredients.

The Hackitt Review described design for compliance culture as a ‘race to the bottom’. Do you think this consultation can turn that around?

Do you agree? Or disagree? How should we bake this particular cake? Have your say by the 10th January 2020!

Additional sources

Avatar for Bertie Dixon

Bertie Dixon

Bertie has practised building services engineering and sustainability consulting in the UK for 15 years. He is a certified PassivHaus planner. He is on a mission to help you deliver a high-quality building, one that does what it says on the tin.

Add comment