Home Insulation Guide

(Are you a renter and wish you could have better insulation? Check out this case study of rental tenants we helped to insulate and upgrade their home – it’s not just for homeowners!)

Insulation is the perfect tool for making your home sustainable, because not only does it make you feel all warm and fuzzy on the inside by reducing your environmental impact and saving you significant amounts of money, it also makes you feel all warm and fuzzy on the outside by keeping your home more comfortable. Without good insulation your heating and cooling systems are wasting energy, no matter how efficient they are.

We sell several different types suitable for ceilings, walls and underfloor installation. We also have experienced installers who can remove old, messy insulation, clean the roof to remove dust and vermin droppings and efficiently and safely install your new insulation.

Here’s some photos from some of our jobs. (We’ll keep adding more)

Every house is a little different, so we organise an obligation-free site visit by one of our installers to measure the area, check for difficult access and recommend whether your ceiling cavity also needs cleaning. This means you get an exact price with no hidden extras on the day.

Average costs for ceiling insulation are usually in the range of:

• $8-$16 per square metre for insulation (depending on R Value and type of insulation)
• $8-$10 per square metre for installation (depending on difficulty and whether joists are standard spacing, if not extra work is required to cut batts to size)
• $8-$12 per square metre for cleaning your roof cavity with an industrial vacuum cleaner (can be higher for very messy roofs)

N.B. Prices are indicative only and may change. The best thing to do is call us for a free site visit and quote – ​0424 754 415, or email insulation@enviroshop.com.au and we’ll get right back to you. We install within the Greater Melbourne area and Central Victoria around Castlemaine / Newstead.

Polyester Batts

Polyester batts are the best option for long-lasting effectiveness, ease of handling, and comfort. Made from up to 85% recycled content, polyester batts are irritant-free, unaffected by mould, mildew and rot, resistant to vermin, and fully recyclable at end of life. They contain no chemical binders, insect repellents or fire retardants, meaning no off-gassing or other health and safety concerns. They will not catch fire and are fully compliant with Australian Building Safety Standards. Polyester has excellent long term stability so won’t compact and lose its potential to block heat flow, unlike many ‘natural’ insulation materials. Our recommended brands are made in Australia under strict quality and environmental controls and meet all relevant Australian Standards and Building Codes.

We supply Autex and Polyester Solutions batts, both locally made out of recycled materials.

Glasswool Batts

Made from recycled glass bottles and sand, Earthwool uses a binder made with renewable materials.

This binder uses 70% less energy in production than conventional petrochemical binders, and makes the batts easier and safer to handle than traditional glasswool insulation – without off-gassing formaldehyde or other VOCs. It also has the other benefits mentioned above of being very stable and naturally resistant to attack by mould, vermin and fire.

Reflective Insulation

Batts are only one part of the insulation equation, you also need something to handle the radiant heat transfer. The best way of doing this is with Kingspan Air-Cell, a layer of closed-cell foam between two sheets of reflective material, which reflects radiating heat back to where it came from (e.g. the hot underside of your roof). This can be retrofitted to an existing roof by stapling to the underside of the joists. If you’re building, renovating or re-roofing it can be supplied with one side anti-glare coated for easy installation directly underneath the new roofing material.

Other Energy Saving Products

It’s important to find the gaps where your home is losing heat (or letting it in) and seal them up or your main insulating efforts will be severely compromised. We also stock a wide range of products for:

• draught-proofing
• insulating your windows
• auto-shutting lids for exhaust fans
• other handy energy saving solutions

Principles of Insulation

Heat travels from a warmer place to a cooler place, and the rate at which it moves is determined by the temperature difference between the two places and the thermal resistance between them, or how easily the heat energy can move. To keep a room at a comfortable temperature you have to counter this flow of energy, replacing heat lost in Winter and heat gained in Summer.

There are three methods of heat transfer:

1. Conduction

Conduction is heat travelling through a solid object e.g, heat transferring through your ceiling plaster.

2. Convection

Convection is heat travelling via fluid motion, which is primarily air movement in houses. This includes the ‘hot air rises, cool air falls’ principle but also the movement of air through draughts.

3. Radiation

Radiation is the transfer of heat as infra-red energy. This can be clearly felt as heat radiating off a hot brick wall in summer, and is significant in many ways around the home.

Insulating a house is about controlling these methods of heat flow by increasing the thermal resistance. Air is a very good insulator if it can be held still to stop convection. This is how insulation batts work, by trapping lots of air in small pockets, and is also the principle behind double glazing.

Thermal resistance in insulation is measured by the R-value, with higher being better. It is a standardised measurement, so you can compare different types of insulation. R4 means R4, whether it’s polyester batts or a bunch of chicken roosting in your roof. This applies best to conduction and batts, but is also used to compare reflective insulation. Be aware that the R value of reflective insulation may not indicate it’s true effectiveness in a given situation. e.g. it is very effective under a hot tin roof.

The recommended minimum for ceilings in Melbourne is R3, but we recommend R4 – R4.5 as the sweet spot, with prices increasing after that for little extra practical insulation difference.