The Green Gas & Energy

Guide to Heat Loss

Whether you’re upgrading your boiler, installing a heat pump, or just want to know why your living room is always freezing, understanding heat loss is the first step to getting your home heating right.
Our no-jargon, 29-part guide breaks it all down — clearly, practically, and with just the right amount of nerdy enthusiasm.

Pick a section below to dive in.

  • Part 1 - What Is Heat Loss & Why You Should Care?

    Part 1 - What Is Heat Loss & Why You Should Care?

    Learn why heat loss matters and how it shapes every efficient heating system we design.

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  • Green Gas & Energy Part 2 - Room-by-Room heat loss Calculations

    Part 2 - Room-by-Room Calculations

    One-size-fits-all doesn’t work. We break down how to calculate heat loss in each room for perfect sizing.

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  • Green Gas and energy - the knowledge - Part 3 - Surface Areas, U-values & Real-World Surfaces

    Part 3 - Surface Areas, U-values & Real-World Surfaces

    Learn how to measure walls, floors and ceilings — and what U-values really mean for your bills.

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  • Green Gas & Energy - The Knowledge - Part 4 - Part 4 - Ground Floors, Sloped Glass & Thermal Bridges

    Part 4 - Ground Floors, Sloped Glass & Thermal Bridges

    These often-overlooked parts of your home can leak more heat than you think. Here's how we handle them.

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  • Illustration of a radiator emitting heat, with an upward arrow and a dryer timer, representing heating and drying functions.

    Part 5 - Design Temperatures & Thermal Comfort

    It’s not just about air temperature. Discover how we keep your home feeling “just right.”

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  • Diagram illustrating home heating and energy efficiency, including a house with a recycle symbol, a flame icon, an exhaust vent, and arrows indicating airflow and heat exchange.

    Part 6 - Ventilation, Chimneys & ACH

    Draughts, flues and extractor fans all impact your heating — we explain how (and what we do about it).

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  • Stylized illustration of interior home elements including two doors, a brick wall, a cabinet, and steam or heat lines.

    Part 7 - Fabric Heat Loss: U-Values & Areas

    Walls, windows, and doors — how we calculate the heat you’re losing through solid surfaces.

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  • Illustration of a smart home with a shower, heated floor, thermostat, and a smartphone app controlling temperature.

    Part 8 - Bridging, High Ceilings & Smart Adjustments

    Why we apply correction factors for tricky spaces like lofts, vaulted ceilings and cold corners.

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