Insulation: What Should You Focus on First — Walls, Ceiling or Floor?

If you’re planning to improve your home’s insulation, you might be wondering where to start. Should you begin with the ceiling, upgrade the underfloor, or invest in wall insulation first? The answer depends on how your home is built, but in Southland’s climate, where warmth is precious and power bills can climb quickly, your insulation order really matters.

Here’s a clear, homeowner-friendly guide to prioritising insulation upgrades for maximum comfort, efficiency, and value.

Start With the Ceiling: The Most Important Area to Insulate

If you only insulate one area of your home, make it the ceiling.

Why?

Because heat rises, and without ceiling insulation, a massive amount of warmth escapes directly through your roof. In older Southland homes, this can be up to 30–40% of total heat loss.

Signs your ceiling insulation needs attention:

• Rooms cool down quickly after heating
• You feel temperature swings between rooms
• Insulation looks old, patchy, or flattened
• You have dampness or condensation issues

Benefits of upgrading ceiling insulation:

• Immediate improvement in warmth and comfort
• Lower heating costs
• Helps stabilise indoor temperature
• Reduces strain on your heat pump

If your ceiling insulation is more than 10-15 years old and is sinking below the joists, it may not longer perform at its best – upgrading is one of the most cost-effective improvements you can make.  However if you have a thick blanket layer above the joists this will be doing a great job! 

Next Priority: Insulating the Floor

After the ceiling, underfloor insulation is the second-biggest game changer, especially in Southland homes with timber flooring.

Cold air moves under your house, making floors icy and rooms harder to heat. Up to 10–15% of heat loss happens through uninsulated floors.

Signs your home could benefit from underfloor insulation:

• Cold, draughty floors
• Rooms feel chilly at ground level
• Gaps between floorboards
• Higher heating bills during winter

Why underfloor insulation helps:

• Stops cold draughts coming up through the floor
• Makes your home feel warmer underfoot
• Helps your heat pump perform better
• Reduces mould growth and dampness

Insulating your floor is typically quick, tidy, and provides instant comfort.

Walls: The Missing Piece With Huge Impact

Most older New Zealand homes have little to no wall insulation, which means your heat escapes through the largest surface area of your home.

While walls are often thought of last, wall insulation can be one of the most effective upgrades — especially in cold climates like Southland.

Why wall insulation is so important:

• Walls make up the majority of your home’s surface
• They can lose 20–30% of heat when uninsulated
• Insulated walls help maintain stable temperatures
• Big improvements in comfort, dryness, and noise reduction

It can dramatically improve the warmth of older homes that have great ceilings and floors — but still feel cold.

So What Should You Insulate First? A Simple Order to Follow

To get the best results and the greatest energy savings, follow this order:

1. Ceiling insulation

The most important and most impactful.
Do this first — always.

2. Underfloor insulation

Strong second priority.
Helps reduce cold, dampness, and draughts.

3. Wall insulation

The final piece that completes your warm, energy-efficient home.
A game changer for homes that still feel cold even with ceiling and underfloor insulation.

When all three work together, your home becomes significantly warmer, drier, quieter, and cheaper to heat — and your heat pump can finally perform at its best.

Ready to Make Your Home Warmer? We Can Help.

Whether your home needs ceiling, floor, or wall insulation, Awarua Synergy can guide you through the best improvements for your space.

We work across Southland — Invercargill, Winton, Gore, Te Anau, Riverton, Bluff, and Mataura — delivering solutions designed for the tough Deep South climate.

Book your free home assessment today and find out which insulation upgrade will make the biggest difference in your home.