Why your home overheats (and why the air con struggles)
If your place starts warming up before breakfast and turns sweltering by late arvo, you’re not imagining it. Aussie homes take on heat through radiant gain (glass/windows), air leaks (doors, vents, chimneys) and conductive gain (floors). The result? Your air conditioner fights a losing battle, runs longer, and your power bill copes the pain.
The good news: if you block heat at the source, your cooling works less and feels twice as effective. Let’s bust three common myths and show what to do instead.
Myth #1: “A bigger air con will fix it”
Fact: Bigger cooling doesn’t solve the cause of the heat.
Air con treats symptoms. Shade the glass and seal the leaks first so less heat enters in the first place. Do that, and your current cooling suddenly feels more capable.
What to do instead
Fact: Bigger cooling doesn’t solve the cause of the heat.
Air con treats symptoms. Shade the glass and seal the leaks first so less heat enters in the first place. Do that, and your current cooling suddenly feels more capable.
- Block radiant heat at the windows: Morning glare and radiant heat are brutal. Install external blinds if you can. Check the best way to shade a window here.
- Renshade reflective foil cuts the heat load while still letting in soft, natural light (you can see out—no cave vibes). Brilliant on east-facing breakfast windows, west-facing living rooms, skylights, and especially pergolas.
- Seal obvious air leaks: Every gap is a highway for hot air.
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- Gap filler kits tidy up cracks around skirting, frames and vents.
- DraftStoppa covers exhaust fans and 3-in-1 units that otherwise suck conditioned air 24/7.
- Chimney draught stoppers cap the constant up-draft (which includes your air conditioning) from unused fireplaces.
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Result: Lower indoor temps, fewer hot spots, shorter AC run-times, and calmer bills.
Myth #2: “Underfloor insulation is only for winter”
Fact: Underfloor insulation helps in summer too.
Heat moves both ways. In summer, stabilising the floor temperature helps rooms hold onto cool air for longer, so your cooling doesn’t need to cycle as hard.
Where underfloor insulation shines
- Timber floors that heat up after a few hot days
- Rooms over garages or raised floors with airflow underneath
- Homes trying to keep cool air in once the AC has done its job
Result: Rooms feel more stable and comfy, fewer temperature swings, and better performance from your existing cooling.
Myth #3: “Sealing doors is fiddly and never lasts”
Fact: Modern quality door sealing is DIY-friendly and durable.
Old-school foam strips? Fiddly and short-lived. Front and Back Door Draught Proofing Kits are purpose-built to create a reliable, neat seal you can feel instantly—without making the door hard to close.
Pro tip to feel results today
Start with the leakiest door (often the front door). It’s the fastest path to a noticeable comfort upgrade—cooler in summer, cosier in winter, and fewer bugs and smoke sneaking in.
The smart order of operations (works for owners and renters)
If you want immediate comfort without a reno, do this in order:
1. Shade the hottest glass first
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- External shading if you can
- Fit Renshade on the windows that cop the worst sun (east morning / west afternoon).
- Bonus: use on pergolas and skylights for serious radiant heat reduction.
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2. Seal the obvious air leaks
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- Front/Back Door Kits (or Draught Dodgers) for big, instant wins.
- DraftStoppa on bathroom/laundry fans.
- Chimney draught stopper if your fireplace is purely decorative.
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3. Tidy up the sneaky gaps
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- Use clear gap filler around skirting, frames, vents and architraves.
- Cap any unused ducts/vents with simple kits.
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4. Stabilise the envelope
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- Ceiling insulation is the obvious place to start as far as insulation works go.
- For timber and raised floors, consider underfloor insulation to slow heat movement and keep rooms more consistent through heatwaves.
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Renters: You’ve got options. Renshade, gap fillers, and several door sealing products are landlord-friendly and reversible (but why would your landlord want to undo exceptionally good retrofitting products!).
Real-world example: one afternoon, big difference
The problem: Glaring breakfast sun and stuffy late-arvo lounge room.
Actions: Renshade on the east kitchen window + Front & Back Door Kit + DraftStoppas in two bathrooms.
Outcome: Morning glare reduced, surfaces cooler by lunchtime, AC cycles shorter in the evening. Sleeping better the same night.
Why blocking heat at the source beats blasting cool air
- Radiant heat (glass): Windows act like heat magnifiers. Reflect it before it enters.
- Convective leaks (gaps, vents, chimneys): Hot air in, cool air out—24/7. Seal the pathways.
- Conductive gain (floors): Uninsulated timber transfers heat and loses cool; insulation slows the flow.
Do these three and you’re designing a cooler, calmer home—not just fighting a losing battle with the thermostat.
FAQs
Does Renshade make rooms dark?
No. It reflects a big chunk of radiant heat while allowing soft, usable light. You can still see out.
Will door sealing make doors hard to shut?
Not with the right kit. Our Front & Back Door Kits are designed to seal effectively without making doors stiff or sticky.
Is underfloor insulation worth it if I already have ceiling insulation?
Yes. Ceiling insulation is a must; underfloor stabilises temps and helps your cooling hold its gains—especially on timber or raised floors.
I rent. What can I do quickly?
Start with Renshade, gap filler kist, and DraftStoppas. They’re non-invasive, effective, and typically landlord-friendly. If you landlord fusses about this, remind them that Minimum Rental Standards will be enforced from 2027 and those standards will be mandatory.
The bottom line
If you want a house that stays cooler—start by stopping the heat. Shade the glass, seal the gaps, and stabilise temps with underfloor insulation where it makes sense. Then let your air con work less, cost less, and feel more effective.
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