Hello,
I have a basic question:
What is the most energy-efficient way to build my house?
Thank you in advance.
I have a basic question:
What is the most energy-efficient way to build my house?
Thank you in advance.
I assume you are talking about a new build, a single-family house.
If you are aiming for a KfW loan, the house should have 70%, 55%, or 40% of the primary energy demand compared to the reference building defined by the Energy Saving Ordinance (EnEV). Additionally, the transmission heat loss must be lower.
Since the house must be seen as an overall concept, you cannot just say, “Put Styrofoam on the wall and that’s it.” The U-values of all components have to be considered.
So please start by describing what you are planning...
Living area in square meters?
When do you plan to start building?
Is it a detached single-family house, semi-detached, or terraced house?
Do you prefer radiators, underfloor heating, or air heating?
Before you start building, and especially before signing a contract for a turnkey house, please make sure to gather much more information!
I am currently building as well... a single-family house with 112 m² (1206 sq ft) living space, without skylights, bay windows, conservatory, dormers, knee walls, garage, or basement... with underfloor heating, solar for domestic hot water, gas condensing boiler, decentralized ventilation system with heat recovery, and sound insulation.
Small but refined, and achieving KfW 55 standard without applying Styrofoam to the exterior walls. (We see plenty of problems with moisture, ants, pests, wasps, woodpeckers, algae, rot, and so on in our neighborhood, so fortunately we are avoiding those issues.)
The foundation slab should be equipped with XPS perimeter insulation accordingly.
The walls should have a good U-value, so at least 36.5 cm (14.4 inches) thick.
Example: 36.5 cm (14.4 inches) wall with a thermal conductivity (lambda) of 0.09 = U-value 0.237
= for 125 m² (1345 sq ft) of exterior wall area and a 20°C (36°F) temperature difference, heating demand is 14.1 kWh over 24 hours.
Example: 36.5 cm (14.4 inches) wall with a lambda of 0.08 = U-value 0.211
= for 125 m² (1345 sq ft) exterior wall area and 20°C (36°F) temperature difference, heating demand is 12.6 kWh over 24 hours.
Example: 36.5 cm (14.4 inches) wall with a lambda of 0.07 = U-value 0.186
= for 125 m² (1345 sq ft) exterior wall area and 20°C (36°F) temperature difference, heating demand is 11.1 kWh over 24 hours.
So you can save about 20% of heat loss by investing more in better bricks.
But then there is also the roof, foundation slab, and windows.
If all of these are executed with high quality (thermal bridges are avoided)
and the ventilation works with heat recovery... it should already be more efficient than many other houses!
You will also save a lot on investment costs if you do without extras like a basement, conservatory, and so on. Many errors occur when building basements!
(A garden shed will do as well!)
If you are aiming for a KfW loan, the house should have 70%, 55%, or 40% of the primary energy demand compared to the reference building defined by the Energy Saving Ordinance (EnEV). Additionally, the transmission heat loss must be lower.
Since the house must be seen as an overall concept, you cannot just say, “Put Styrofoam on the wall and that’s it.” The U-values of all components have to be considered.
So please start by describing what you are planning...
Living area in square meters?
When do you plan to start building?
Is it a detached single-family house, semi-detached, or terraced house?
Do you prefer radiators, underfloor heating, or air heating?
Before you start building, and especially before signing a contract for a turnkey house, please make sure to gather much more information!
I am currently building as well... a single-family house with 112 m² (1206 sq ft) living space, without skylights, bay windows, conservatory, dormers, knee walls, garage, or basement... with underfloor heating, solar for domestic hot water, gas condensing boiler, decentralized ventilation system with heat recovery, and sound insulation.
Small but refined, and achieving KfW 55 standard without applying Styrofoam to the exterior walls. (We see plenty of problems with moisture, ants, pests, wasps, woodpeckers, algae, rot, and so on in our neighborhood, so fortunately we are avoiding those issues.)
The foundation slab should be equipped with XPS perimeter insulation accordingly.
The walls should have a good U-value, so at least 36.5 cm (14.4 inches) thick.
Example: 36.5 cm (14.4 inches) wall with a thermal conductivity (lambda) of 0.09 = U-value 0.237
= for 125 m² (1345 sq ft) of exterior wall area and a 20°C (36°F) temperature difference, heating demand is 14.1 kWh over 24 hours.
Example: 36.5 cm (14.4 inches) wall with a lambda of 0.08 = U-value 0.211
= for 125 m² (1345 sq ft) exterior wall area and 20°C (36°F) temperature difference, heating demand is 12.6 kWh over 24 hours.
Example: 36.5 cm (14.4 inches) wall with a lambda of 0.07 = U-value 0.186
= for 125 m² (1345 sq ft) exterior wall area and 20°C (36°F) temperature difference, heating demand is 11.1 kWh over 24 hours.
So you can save about 20% of heat loss by investing more in better bricks.
But then there is also the roof, foundation slab, and windows.
If all of these are executed with high quality (thermal bridges are avoided)
and the ventilation works with heat recovery... it should already be more efficient than many other houses!
You will also save a lot on investment costs if you do without extras like a basement, conservatory, and so on. Many errors occur when building basements!
(A garden shed will do as well!)
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