How to qualify for 6-star energy rating (pre NCC 2022)

firsthyme · Apr 20, 2024 6:50 pm

Hi, I'd like to enquire on the new changes regarding the 7 star energy rating brought about by the NCC 2022 for Victoria.

For people with house builds under way, what is the specific cut-off point that allows you to stay with the previous NCC (i.e. 6 star energy rating only)? The goal is to not blow out costs in trying to meet 7-star energy rating requirements (although I do plan to upgrade as much as I can to be as energy efficient as possible regardliess).

For context, we've been working with the builder over the last 1-2 years and very close to contract stage. However, I'm hearing mixed information about how I can guarantee to be able to stay with the old NCC (i.e. 6 star energy rating).

1. Some have told me that I've done the bulk of planning/designs now, so I'd quality to adhere to 6-star energy ratings.

2. Others have told me that the contract has to be signed by 1st Jun 2024, because a signed contract is what is used to determine the cut-off period. Currently if we go with this route, since we haven't fully finished with the plans & design (need approx 1 more month after 1st June) - which might mean a huge shock in terms of post-contract variations, so I'm very weary of signing a contract without knowing the final costs.

Can someone please advise on the cut-off date (and what exactly needs to happen?)

Thanks

Bimbob · Apr 21, 2024 12:31 pm

By whenever you signed the contract.
But you should be working towards 7 star anyways, especially being in Vic, itll provide for a better house overall

firsthyme · Apr 21, 2024 11:14 pm

Bimbob Thanks for that clarification.

Actually one of my friends just reached out today and mentioned it's actually when the permit is approved (which I'm guessing is usually after contract right?) I recall my builder mentioning that the permits are only sent for approval once the contract is signed?

Also - do you have any information / experience in understanding what it generally takes to get from 6 to 7 star? And what the costs usually are? It would be good to get some real practical examples and information on what usually needs to change (and around how much it would be).

There's a lot of windows (not so much west-facing) in our place, and that is one of the main things we were looking for. I'm hoping (and also wondering) that we can keep this and still meet 7-stars?

firsthyme · Apr 21, 2024 11:47 pm

Also just to add. I'm not sure what the energy rating will be (not sure if it will come through in the final plans which I'm due to get this week) but I've already asked them to include the following:

- All internal & externall wall insulation to be R2.7 (highest they can go apparently)
- Colorbond roof has Anticon 1.3
- Upgraded ceiling & between floor insulation (double storey house)
- Planning to get biggest solar panels that I'm allowed to
- Want the garage to be ready for EV charging
- Planning to go for a heatpump electric hot water system

I'm not sure how much 'impact' the above have - but I wonder how closer those upgrades make me closer to 7-star energy rating?

Or is there more than just 7-star energy rating? Does NCC2022 come with a bunch of other changes that my building design would have to adhere to as well?

Bimbob · Apr 22, 2024 6:45 am

Doh!!, your right, Permit approval. Sorry about that.

Im not familiar with Vic but speaking of 7 star thermal comfort wise you could do the following:

Insofar as 6 vs 7 star and the steps to take to acheive this I suggest the following (without reviewing your plans):
- All internal & externall wall insulation to be R2.7 (highest they can go apparently) Yes, heighest available in a 90mm wall, Increase insulation where ever you have it. R2.7 is great, beaware that R2.7 is 90mm thick. If not installed to code (and you can near on guarantee it wont be because know one does) it may impreach on your external wall wrap.
- Colorbond roof has Anticon 1.3 - How about R1.4 or 1.8?
- Upgraded ceiling & between floor insulation (double storey house) - You could go R4.1 if you have the space here or higher in ceilings, just need to manage you joist centers to allow for additional weight
- Planning to get biggest solar panels that I'm allowed to - no impact (thermal comfort wise) but great idea
- Want the garage to be ready for EV charging - no impact (thermal comfort wise) but great idea
- Planning to go for a heatpump electric hot water system - no impact (thermal comfort wise) but great idea
Double glaze all windows
I not too late, raise or lower window sills to allow/ block direct sun
Reduce/ increase window sizes
Change sashes to awning over sliding
Use thermally broken, PVC or timber window frames
Sun shading devices to windows
Ceiling fans
Reduce the number of ceiling penetrations that require insulation to be removed
Ventilate cavities (check this is relevant for your climate zone)

Im sure theres more but that all I can think of for now.

NCC2022 comes with a raft of changes, the most important being condesation management. Keep on top of this given youre region.

ponzutwo · Apr 23, 2024 8:33 am

So I have a bone to pick with the star ratings. I built a 7.2 star home about 10 years ago. It is no where near as comfortable to live in as the 6 star i built a year and a half ago. Straight of the bat, the cost to cool and heat the home was more expensive back then than my current larger house with higher electricity prices. Go figure.

Do the smart stuff like insulation etc, but temper your expectations between the differences

Bimbob · Apr 23, 2024 8:37 am

maybe it was rated at 7.2 but not built at 7.2?

ponzutwo · Apr 23, 2024 10:58 am

Bimbob

maybe it was rated at 7.2 but not built at 7.2?

Doubtful. Everything that was listed in the report was installed as per plans and independently verified multiple times throughout the build.

While i appreciate there's some science behind the calculations that inform the ratings, I don't think the outcomes apply as consistently as one would think.

awratten · Apr 23, 2024 11:06 am

ponzutwo

So I have a bone to pick with the star ratings. I built a 7.2 star home about 10 years ago. It is no where near as comfortable to live in as the 6 star i built a year and a half ago. Straight of the bat, the cost to cool and heat the home was more expensive back then than my current larger house with higher electricity prices. Go figure.

Do the smart stuff like insulation etc, but temper your expectations between the differences

10 years ago was a different software than we use now. it has had a lot of changes over the past years. Improvments to the software and changes to how Nathers models need to be conducted have made it more stringant. If you modeled your old 7.2 star house now it would probably go down to around 6.5 stars ish. also the energy rating assumes the build reaches a minimum air-changes, but if the builder does not reach this level of sealing then the actual energy usage will be significantly higher.

Linked in article "Read Between the stars" by Brian Haines