Building? Which insulation is best for you?

Building a new home is exciting, but have you decided on insulation yet?

The right insulation, installed correctly, can make a dramatic difference to both the ‘livability’ of your home, greenhouses, playhouses and other buildings, as well as your household budget. By keeping your home at a comfortable temperature, you can reduce your energy consumption and save money on your energy bills.

The best, easiest and cheapest time to insulate your new home!
The best, easiest and cheapest time to insulate your new home!

Home insulation is not a cookie-cutter project; it is a customized plan based on several elements. Each home is different, having unique insulation needs and requirements.  Factors to consider include the home’s design, structure, cooling and heating systems, location, and climate. However, one thing remains true: homes need proper insulation.

Is insulation necessary?

Absolutely, regardless of your location. Insulation is the most viable and cost-effective way to make sure that your home is energy efficient so that it is warmer inside your home during the cold season and cooler during the hot season.

Proper insulation allows you to save as much as 80 percent in cooling and heating losses. Plus, it also reduces condensation inside your home. Properly installed, it guarantees that the home is free from drafts and moisture ensuring comfort and durability for many years.

Places to insulate

The next step to knowing the necessity of insulation is knowing where to insulate. It is important to insulate attics/roof spaces, basements, crawl spaces, ducts, floors, sill plates, walls, windows, and other places where you might feel a draft. Start at the attic/roof space as it is where most of the heat escapes.

Insulation materials

Insulation materials provide heat resistance to your home. These slow down three heat mechanisms: conduction, convection, and radiation providing you a safer and more comfortable home.

There are different materials used in insulating different areas in the home. Here are some of them:

  • Blanket: batts and rolls

This is usually made of fibreglass and rock wool and is fitted between beams, joists, and studs. This type of insulation is applicable on all unfinished floors, walls, and ceilings.

Most homes use fibreglass because it is the cheapest, using plastic that is fortified by fine glass fibres. It comes in blanket or loose-fill form, preventing heat, cold, and even some sound from dispersing in your home.

Fibreglass batts are installed in walls, floors, and ceilings, and can even be fitted between studs, joists, and beams. It has air bubbles inside it that prevent energy from phasing through the material, which keeps heat from exiting your home.

Like cellulose, fibreglass is widely used in structures because of its low-cost installation. Almost 90 percent of new homes in the United States are insulated using fibreglass.

  • Foil reflective insulation

This is an insulating material made from aluminium foil laminated on plastic or paper. During summer it reflects heat accumulated on the roof and walls and during winter it restricts heat from escaping. This way you don’t need to expend as much energy to heat or cool your home.

  • Insulating concrete forms (ICFs)

When constructing walls for new homes, insulating concrete forms (ICFs) are also used nowadays. These are special concrete walls that help lessen the effects of temperature changes outside.

  • Loose fill and Blown-In insulation: Cellulose

This material uses recycled materials, making it relatively cheap. It is installed either as loose fill or is blown in. It is typically 80% recycled newsprint or denim mixed with non-toxic borate compounds. The chemicals present make it resistant to fire, mould, and insects because its fibres are tightly packed together.

For maximum insulation benefits, consider building to passivhaus standard.
For maximum insulation benefits, consider building to Passivhaus standard.

Cellulose is hygroscopic, capable of holding and absorbing water without tearing. It also prevents heat from being trapped and spreading to other parts of the house.

Lastly, cellulose is a widely used material because it’s one of the oldest. Home builders have made this their insulator since the 70s because of its consistently low cost.

  • Spray foam

This material combines the notable aspects of the other insulation materials. It’s environment-friendly like cellulose because it uses organic chemical compounds from petroleum extracts. It also controls sound better and is applied to any surface, similar to fibreglass.

Spray foam produces one of the best heat barriers because it spreads throughout the surface without leaving any space unoccupied. You can choose between open-cell spray for light surfaces or closed-cell spray foam for dense surfaces.

Once combined, the chemicals used in spray foam produce one of the best measures to battle temperature. Though it is the most expensive, it’s worth a second look because of the coverage it gives per application.

Spray foam usually scores the highest R-value because it fills the gaps and crevices of the surface. It is the priciest for a purpose – it won’t sag or settle over time, denying the three heat mechanisms from spreading.

Like most building materials, insulation materials are labelled according to their strength. They’re governed by R-values, which determine the thickness, density, and type of insulation. Temperature, aging, and moisture accumulation are also considered in scoring a material’s R-value. Effectiveness increases as the R-value increases. In other words, R5 is a higher rating than R4.

Can you ‘over-insulate?

If you live in a mild climate, it’s easy to assume you can save a few dollars by using a lower-cost (R-value) material. For example, if you live in a temperate zone the guidelines might suggest that R2.5 is adequate. But the trap is in that word ‘adequate’. Climate is changing. Extremes are more common. It is on those extreme days that you’ll regret the relatively minor savings.

Labour costs are going to be constant whether you use R2.5 or R4 batts. Sure the materials will cost more, but do the sums and then determine the likely future benefits.


A well-insulated home will reward you in comfort. And the insulation will pay for itself over time… perhaps sooner than we think, given the way power prices are increasing. It’s important to make the right choice based on both your environment and, to a much lesser degree, your budget. It is much more expensive to retrofit insulation than it is to forego that third toilet. The former will reward you every day while the latter will only add to your cleaning chores 🙂

Take time to read up on insulation alternatives. Then speak to an expert to confirm your decision. And then, call for quotes. Like everything in the building industry quotes can vary significantly for identical items. And if your budget is tight – isn’t everyone’s? – consider installing the insulation yourself. It’s an easy job as long as you understand that both heat and cold will find any gaps you leave!

Plan for both aspect and climate:

Building to the prevailing aspect can also dramatically reduce heating and cooling costs. The best aspect is usually south in the northern hemisphere and north for those living south of the equator. All too often, budget and/or the view dominate siting decisions. Does that ‘project home’ really suit the position?

Build to suit the aspect AND your climate and you will save a fortune over time.
Build to suit the aspect AND your climate and you will save a fortune over time.

Are the eaves going to protect you from the summer sun and winter rains? Should those big windows really be on the western side? There are many ways to capture a view without compromising aspect considerations. Design and build for the long haul.

If you are planning on insulating an existing home, read our previous post on Insulation Options for Existing Homes.  If you have recommendations, suggestions, and opinions, do let us know in the comments section below.



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