📐 Shape & Area
A square house 10 metres wide × 10 metres long. Total area: 100 sq.m.
The "10x10 Model": The Heat Loss Laboratory - How We Measure Consumption
If you have ever searched for thermal insulation, you have surely been bombarded with confusing terms: thermal transmittance coefficients, thermal resistance, and lambda values. But at the end of the day, what everyone really cares about is one simple, practical question: "How many euros and how many kilowatt-hours (kWh) will I save in winter by insulating?"
To answer this with scientific precision throughout all articles in our guide, we created the "10x10 Model". It is our own digital laboratory. A typical, uninsulated Greek home, which we use as a baseline (Base Case) to "test" every insulation material, every window and every intervention technique.
Here, we make the invisible (heat) visible and measurable.
1. The Blueprint: How Our Model Is Built
To ensure our calculations are realistic and easily transferable to your own square metres, we defined a home with simple geometry that reflects the construction practices of the 1970s and 1980s in Greece.
🏠 Ceiling Height
3 metres. The total air volume to be heated is 300 cubic metres.
🧱 Walls
120 sq.m. gross wall area (4 walls × 30 sq.m.).
🪟 Windows
15 sq.m. of windows and balcony doors (≈15% of floor area). Net wall area: 105 sq.m.
🏗️ Flat Roof
100 sq.m. of reinforced concrete slab.
🏠 Floor
100 sq.m. of floor resting on an uninsulated pilotis or on the ground.
2. The Assumptions: "Ground Zero" (Uninsulated State)
At this stage, our home is completely "naked" in energy terms. No renovation has taken place. The table below shows the building elements and their initial thermal transmittance coefficient (U-Value). The higher the number, the more heat "escapes" to the environment.
| Building Element | Material (Uninsulated) | Area | U-Value |
|---|---|---|---|
| Walls | Single-leaf brick wall with plain render | 105 sq.m. | 2.50 W/(m²K) |
| Flat Roof | 15cm concrete slab, no insulation, simple fall | 100 sq.m. | 3.00 W/(m²K) |
| Floor | Concrete slab, mosaic or tiles (above pilotis) | 100 sq.m. | 2.20 W/(m²K) |
| Windows | Old aluminium (no thermal break) + single glazing | 15 sq.m. | 5.50 W/(m²K) |
3. The Physics Behind the Numbers: How We Calculate Losses
To calculate how much energy the heating system (radiators, A/C, heat pump) must consume just to replenish the heat lost through walls and glazing, we use the fundamental transmission heat loss formula:
🧪 The Formula: Q = U × A × ΔT
Q: Rate of heat loss (Watts).
U: Thermal transmittance W/(m²K).
A: Area of the building element (sq.m.).
ΔT: Indoor-outdoor temperature difference.
🌡️ The Test Scenario
We want a steady indoor temperature of 20°C. Outside: a typical winter day at 5°C. Difference: ΔT = 15°C.
⚡ The Result
Applying the formula, the 10x10 Model loses approximately 10,300 Watts (10.3 kW) of thermal energy every hour at "Ground Zero".
🔴 Annual Consumption
Over a typical Greek year, this translates to consumption reaching or exceeding 200 kWh per sq.m. annually. A home that is literally an energy black hole, heating the neighbourhood instead of its occupants.
4. How We Will Use This Model in the Following Articles
In the articles that follow in the Insulation Guide, the 10x10 Model will receive virtual "upgrades". You will frequently see a box like the following:
💡 The 10x10 Model Experiment: What happens if we wrap the walls with external insulation (EPS) 7cm thick? The U-Value plummets from 2.50 to 0.45 W/(m²K). Wall heat losses are reduced by 82%, saving hundreds of euros in electricity or oil.
🎯 Compare Interventions
You will be able to instantly compare whether it is better to first replace old windows or insulate your flat roof.
📐 Common Baseline
Everything based on the same 100 sq.m., with the same mathematics, completely measurable.
💰 Results in Euros
Every "upgrade" will show exactly how many euros and kWh it saves, so you can make decisions based on real data.
Related Articles
Thermal Physics & Calculations: From Theory to kWh and Euros Insulation Systems: Complete Solutions for Every Building Application & Construction Details: Correct Installation Guide Ventilation, Airtightness & Real Consumption: Climate Control
The Ultimate Guide to Thermal Insulation & Energy Protection
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