Boiler & Boiler-House Insulation: Heat Loss & Savings
The boiler house runs hottest and longest, and bare doors, burner flanges, manways and valves there usually have the fastest payback in the whole plant. Removable insulation covers the parts that fixed cladding can't.
Heat loss vs insulated — by surface temperature
| Surface temp | Bare loss | Insulated | Outer surface | Reduction |
|---|---|---|---|---|
| 80 °C | 1,010 W/m² | 55 W/m² | 24 °C | 94.6% |
| 120 °C | 1,839 W/m² | 99 W/m² | 27 °C | 94.6% |
| 180 °C | 3,394 W/m² | 180 W/m² | 32 °C | 94.7% |
| 250 °C | 5,822 W/m² | 154 W/m² | 30 °C | 97.4% |
Per-m² flat-surface flux, ASTM C680 / ISO 12241, 50 mm Lamella (≤220 °C) or 100 mm Wired mat (>220 °C), 20 °C ambient. Multiply by the bare area.
Worked examples (per year, 8,000 h, natural gas)
| Item | Heat saved | Energy/yr | CO₂/yr | € saved/yr |
|---|---|---|---|---|
| A boiler front door (5.1 m², 90 °C) | 5.8 kW | 55 MWh | 11.0 t | €3,171 |
| A burner / blower flange (1.43 m², 120 °C) | 2.5 kW | 23 MWh | 4.7 t | €1,358 |
FAQ
How much heat does a bare boiler lose?
At 20 °C ambient (ASTM C680): a boiler front door (~5.1 m², 90 °C) loses about 5.8 kW; a burner / blower flange (~1.43 m², 120 °C) about 2.5 kW. Insulating a boiler front door saves ≈55 MWh and ≈11.0 t CO₂ per year (8,000 h).
Can you insulate boiler doors and similar?
Yes. Boiler doors, manways and burner assemblies are opened for inspection and servicing. Removable covers refit each time without damage. Inzonex covers boiler doors, manways, burner flanges, blowdown and feed-water fittings. The outer surface drops to a touch-safe ≤45 °C and the part stays serviceable.
How much does boiler & boiler-house insulation save?
Each item saves 96–98% of its bare loss. A boiler front door at 90 °C saves ≈3,171 €/yr of energy (≈55 MWh, ≈11.0 t CO₂) at typical gas prices; payback is usually under two years.
What insulation thickness is used?
Up to 220 °C surface: 50 mm mineral-wool (Lamella); above 220 °C: 100 mm (Wired mat), because conductivity rises with temperature. Both keep the outer surface ≤45 °C.