BBC: 3G may be 'required' from 2025

[Ferdinand]

Quite an interesting piece on the BBC suggesting that 3G may be effectively standards under the new building regs.

 

including a new type of 3G called "Architectural Technical Glazing' - U-value ~0.5 - with a very thin centre pane, which is supposed to make it more practical as a 2G replacement.

 

I'm not completely convinced, since glazing is only one aspect and 2G is available at a U-value of under 1.

 

As ever, imo it will be down to how to meet the minimum requirement at the minimum price.

 

https://www.bbc.co.uk/news/business-67161076

 

[SteamyTea]

People have bought into 'lots of natural light'.

So while in terms of exposed area, windows may only account for 25% or less, they can have a disproportionate affect on the heat losses.

So I am all for improvements.

 

Technically the glass adds little to the overall U-Value, so adding a thin pane in the middle is a sensible thing to do.  A 1mm or thinner sheet of cast acrylic would do as it will reduce the convection currents.

[IanR]

Hopefully tangible details of the 2025 Future Homes Standard will start to emerge soon as the changes are pretty significant, and the industry needs to prepare.

 

Reportedly, homes completed to the 2025 Buildings Regs will produce 75% - 80% less CO2 than the homes built to pre-2022 regs.

 

If that's allowing for homes heated with today's Electricity mix v. Gas, there has to be a significant uplift in fabric performance as well.  I'm not sure Architects are ready for it, let alone the volume builders.

Edited November 14, 2023 by IanR

[craig]

17 hours ago, SteamyTea said:

People have bought into 'lots of natural light'.

So while in terms of exposed area, windows may only account for 25% or less, they can have a disproportionate affect on the heat losses.

So I am all for improvements.

 

Technically the glass adds little to the overall U-Value, so adding a thin pane in the middle is a sensible thing to do.  A 1mm or thinner sheet of cast acrylic would do as it will reduce the convection currents.

 

It will make many window manufacturers and suppliers up their game or go out of business (a good thing).

 

16 hours ago, IanR said:

I'm not sure Architects are ready for it, let alone the volume builders.

 

They really need to up their game, we have a lot of catching up to do.

[JohnMo]

Hope they are sensible enough to state whole window U values and not just centre pane values. Good glazing in a bad frame makes for rubbish overall U values.

 

When I was looking for windows for our house, started with double glazed, asking for 1.2 U values, got quotes back at 1.8, when questioned we can't get the frames you need? And no we don't do triple glazed, they do not make financial sense. Most suppliers are in general pretty rubbish.

 

Ended up custom built triple glazed.

On 14/11/2023 at 19:23, IanR said:

Reportedly, homes completed to the 2025 Buildings Regs will produce 75% - 80% less CO2 than the homes built to pre-2022 regs.

You have to very careful when you read statements like that, are they comparing apples with apples, or an orange? Having a heat pump instead of a gas boiler gets to almost that CO2 saving on its own, especially if you forecast the grid CO2 intensity to 2025 and use 2022 as your baseline for comparison.

[IanR]

2 minutes ago, JohnMo said:

You have to very careful when you read statements like that, are they comparing apples with apples, or an orange? Having a heat pump instead of a gas boiler gets to almost that CO2 saving on its own, especially if you forecast the grid CO2 intensity to 2025 and use 2022 as your baseline for comparison.

Indeed, hence me including

 

On 14/11/2023 at 19:23, IanR said:

If that's allowing for homes heated with today's  Electricity mix v. Gas,

However in 2025 that will not deliver anywhere near a 75% - 80% reduction in CO2, and will require "significant uplift in fabric performance as well". 

[Kelvin]

Upping standards is a good thing but how well the windows are fitted has a bigger impact. Fitting smaller windows bigger still. We have done the whole wall of glass thing largely because we have a very nice view on the south elevation and it’s why we bought the plot. If it was a different view I’d have removed half the windows. 

[JohnMo]

1 minute ago, Kelvin said:

We have done the whole wall of glass thing largely because we have a very nice view on the south elevation and it’s why we bought the plot. If it was a different view I’d have removed half the windows

We are the same. But that one wall of glass , triple glazed as it is, looses as much heat as the roof, floor and walls all added together 

[Kelvin]

Yep. Building a house is a compromise. I was on-site before the sun was up this morning. I sat on my folding chair by the big wall of glass sipping my tea watching the mist roll up the valley. I’m happy with my comprise. 

Edited November 16, 2023 by Kelvin

[Ferdinand]

On 14/11/2023 at 19:23, IanR said:

Hopefully tangible details of the 2025 Future Homes Standard will start to emerge soon as the changes are pretty significant, and the industry needs to prepare.

 

Reportedly, homes completed to the 2025 Buildings Regs will produce 75% - 80% less CO2 than the homes built to pre-2022 regs.

 

If that's allowing for homes heated with today's Electricity mix v. Gas, there has to be a significant uplift in fabric performance as well.  I'm not sure Architects are ready for it, let alone the volume builders.

 

That's quite a big jump on one go.

[IanR]

4 hours ago, Ferdinand said:

 

That's quite a big jump on one go.

It is. But, I'd assume that figure includes the change from gas to ASHP, for the average new build. If the average new build would achieve a SCOP of 2.5, then 40% points of the reduction is coming from the change in heating source. Still leaving a 35% - 40% improvement in building fabric performance, some of which has already been achieved with the 2022 Regs changes.

[Iceverge]

Its a shame to see the creeping grinding incrementalism. Its like being on a train  that stops at every station rather than just getting the express to the destination many of us here have realised. 

 

Build a passivhaus out if things that used to be plants and add lots of solar and an ASHP.