Energy: poor insulation, money wasted every winter
Hi, this is Claude. Poor insulation in a home, especially around windows, lets the heat escape and drains your wallet every winter. Acting quickly with simple solutions will reduce your energy bills and improve your thermal comfort without breaking the bank.
To do immediately
- Check for drafts around windows to detect leaks.
- Replacing worn seals is quick and inexpensive.
- Install a window film to limit heat loss.
- Use thermal curtains to increase the barrier against the cold.
- Simulate your financial aid such as MaPrimeRénov’ to reduce costs.
According to ADEME, your windows can represent between 10 to 20% of heat lossesWith soaring energy prices, heating costs increase even further if you leave these heat losses unaddressed. To understand in detail how to identify a poor insulation and its effects, or how to avoid these losses with simple actions, consult these valuable resources. Stop wasting money unnecessarily is within easy reach.
Detecting poorly insulated windows: signs not to miss
The key is to observe your house when it’s cold. If you feel a draft even with the window closed, that’s a strong sign. Condensation on the inside of the glass often indicates a thermal bridge or a ventilation problem. Cold walls and a persistent feeling of cold despite the heating also indicate poor insulation. These signs shouldn’t be ignored, because, as the renovation expert reminds us: “A leaky house means wasted energy and money.”
Don’t wait to act: 9 practical solutions tested and ranked
Marc, who lives in a 1960s house, has experimented with these solutions, from the simplest to the most sustainable. Here’s how you too can reduce your bills:
- Replace the seals (€5 to €30): small investment, great comfort, and immediate effect on drafts.
- Bubble wrap on the window (~15 €): discreet and effective DIY, especially for rarely used parts.
- Journal to fill the gaps (€0): emergency repairs.
- Window film (€10 to €30): creates an insulating air gap, a good intermediate step.
- Thermal curtains (15 to 80 €): reflect the cold outwards, combined with the film, it is very effective.
- Overglazing (€70 to €120 / m²): a second glazing that significantly reduces losses.
- Replace the door panels (€250 to €700): useful if the sash is damaged, with double glazing recommended.
- Install insulated shutters (€250 to €800): excellent thermal barrier, especially in exposed areas.
- Double or triple glazing (€300 to €1,500): for very old windows, this is often the most profitable investment in the long run.
If it’s an old house, starting with the seals and then double glazing is often the most cost-effective solution.
If you’re renovating from scratch, aim directly for double or triple glazing to optimize costs and comfort.
Comparative table of glazing options to help you choose the best option
| Type of glazing | Thermal insulation (Uw) | Indicative cost / window |
|---|---|---|
| Single glazing | Low (~5.8 W/m².K) | Economic reference |
| Double glazing | Good (1.2 – 1.8 W/m².K) | €300 – €1,000 |
| Triple glazing | Excellent (0.7 – 1.0 W/m².K) | €800 – €1,500 |
As you can see, each type has its advantages depending on your budget, the orientation of your house, and the rooms to be insulated. Triple glazing is very popular in cold climates, but sometimes double glazing is more than enough to limit energy inefficiency.
2025 subsidies to reduce your energy costs
In addition to directly reducing your high bills, you can finance these renovations with MaPrimeRénov’, the zero-interest eco-loan, and energy savings certificates (CEE). Marc saw a significant initial decrease in the first year thanks to these subsidies and the reduced VAT rate of 5.5% on materials and professional installation. Don’t rush into it: first, simulate your eligibility to minimize your out-of-pocket expenses.
3 easy steps to improve your insulation this winter
- Step 1: It accurately diagnoses air leaks and thermal bridges by inspecting windows and walls.
- Step 2: Replace the seals, lay down an insulating film and install thermal curtains for a quick effect.
- Step 3: Prepare for major renovations by requesting several quotes and putting together your grant application to replace windows or install insulated shutters.
A quick reminder: you gain comfort and you also protect your home from humidity and deterioration! Neglecting thermal insulation means losing money and lasting well-being.
How to recognize poor thermal insulation?
Look for signs such as condensation on windows, cold walls, drafts around windows, and a heating bill that rises for no apparent reason.
What is the most economical solution for limiting heat loss?
Changing the seals and installing a secondary glazing film are the most economical actions with a good effect on thermal comfort.
Is double glazing still necessary?
Not always, but it often reduces heat loss through windows by half compared to single glazing.
What financial assistance is available in 2025?
MaPrimeRénov’, the zero-interest eco-loan, CEE certificates and the 5.5% VAT are the main forms of assistance to consider.
Why does poor insulation increase energy bills?
Because it forces heating and air conditioning systems to run longer to compensate for heat loss or overheating.
Thank you for your interest; Claude
