Insulmax Insulation. Who has

this in their home or do you know if it is effective and keeps the warmth in.
Thanks.

Needs a 35mm hole in every single cavity (ie between every stud/dwang) to blow it in. Likely the remediation would cost more than de-gibbing and using decent stuff like Woolbloc.

Insulmax is a brand of insulation that is made from recycled paper fibers and is designed to be blown into walls and ceilings for thermal insulation. While Insulmax has many benefits, there are also some potential problems that homeowners should be aware of. Here are a few of the most common issues:

1. Moisture retention: Insulmax is made from paper fibers, which can absorb and retain moisture. If the insulation becomes wet, it can lose its insulating properties and become a breeding ground for mold and mildew.
2. Settling: Over time, Insulmax can settle and compress, which can reduce its insulating effectiveness. This settling can also cause walls and ceilings to sag or bow.
3. Fire resistance: Insulmax is treated with fire retardants to make it more resistant to fire. However, the insulation is not completely fireproof, and it can ignite and burn under certain conditions.
4. Pest infestation: Insulmax can attract pests such as rodents and insects, who may use the insulation as nesting material. This can lead to pest infestations in the home.
5. Installation issues: Proper installation of Insulmax is critical to its effectiveness. If the insulation is not installed correctly, it can leave gaps or voids that reduce its insulating properties.

If you are considering using Insulmax in your home, it's important to weigh the potential benefits and drawbacks carefully. Consult with a professional insulation contractor to ensure that your insulation is installed correctly and to minimize the risk of any potential problems.

Don't do it especially if there is no building paper behind the weatherboards or exterior cladding. Especially don't do it if you have brick exterior cladding. Bricks allow water through and must be able to drain down the inside face and drain out the bottom. Blown in insulation will trap that moisture and your walls will rot from the inside. None of the blow in wall insulation methods have BRANZ approval. Read this from BRANZ (Building Research Association NZ)
https://www.renovate.org.nz/bungalow/insulation/

I agree with you but surely the external cladding would be waterproof or the building will have failed by now?

OP hasn't told us what the external cladding is or the age of the house. However if it is pre 1960s and weatherboard the framing will probably be native timber which has some resistance to decay provided there is air movement to let it dry out. If you fill the walls with insulation you stop the drying process or worse still the insulation acts like a sponge and even native timber will rot if it is constantly damp. All claddings will let some moisture in which is why modern houses are built with a drained and ventilated cavity behind the cladding. Also it is not just water coming in from the outside. The warm air inside the house will hold moisture but cold air outside is dry. There will be a "dew point" inside the wall cavity where the moisture in the air inside the wall condenses out - most likely on the inside face of the exterior cladding, like how moisture in a warm room condenses on a cold single glazed window. That moisture the condenses in the wall cavity needs to be able to dry out and air flow is the best way to achieve that.