Wall and Ceiling insulation upgrade

Mahendar Muthu · Jul 16, 2020 3:19 pm

Hi There,
Our builder is providing R4.1 ceiling insulation and R2.5 wall insullation. But we are planning to increase the ceiling insulation from Bradford R4.1 to 6.0 and for walls - R2.0 to R2.5. We tried doing some research but couldn't find if that's worth. Any advice will be really healpful.

Thanks,
M

dga · Jul 16, 2020 3:26 pm

It depends on where you're located, but in general more insulation is better. But there comes a point where the extra performance is marginal, and the costs outweigh the benefits.

We're south of Sydney near the ocean, and have 5.1 (3.5 + 1.6 anticon) in the roof, and 2 in the walls. We have no heating or cooling, and I'm walking around in the evening in shorts and a jumper and am perfectly comfortable - so from experience so far it's not work upgrading (noting we haven't had a summer yet).

But if I was in a more extreme climate area, like Tasmania, North Queensland or western NSW, it may well be.

This is a good resource

https://www.yourhome.gov.au/passive-design/insulation

BROKEANDEXCITED · Jul 16, 2020 7:02 pm

Where the curve is more vertical is where most of the action occurs. Once it starts flattening out, you get less and less from more and more.

I decided that I was happy with R 4.0 for roof as the incremental gain is not much by upgrading

https://www.energyvanguard.com/blog/769 ... Insulation

Mahendar Muthu · Jul 19, 2020 11:40 am

dga

It depends on where you're located, but in general more insulation is better. But there comes a point where the extra performance is marginal, and the costs outweigh the benefits.

We're south of Sydney near the ocean, and have 5.1 (3.5 + 1.6 anticon) in the roof, and 2 in the walls. We have no heating or cooling, and I'm walking around in the evening in shorts and a jumper and am perfectly comfortable - so from experience so far it's not work upgrading (noting we haven't had a summer yet).

But if I was in a more extreme climate area, like Tasmania, North Queensland or western NSW, it may well be.

This is a good resource

https://www.yourhome.gov.au/passive-design/insulation

Thank you. Yea, it makes sense.

Mahendar Muthu · Jul 19, 2020 11:41 am

BROKEANDEXCITED

Where the curve is more vertical is where most of the action occurs. Once it starts flattening out, you get less and less from more and more.

I decided that I was happy with R 4.0 for roof as the incremental gain is not much by upgrading

https://www.energyvanguard.com/blog/769 ... Insulation

Thank you, looks like adding more insulation will help little.

stonesthrow · Jul 21, 2020 12:58 pm

I think 4 to 6 there is still a decent amount of gain but beyond that there is no need. Most high performing non-passivehaus (still reasonably affordable) houses I've seen are spec'd at R6 in the ceiling. But yeah, depends on a lot of things.