From energy labels to kilowatt-hours

De Duurzame Oplossing's calculations start from four principles: how the home performs in energy terms, where it is located, how its residents behave, and the factor of time across the whole year.

The home as a physical system

The philosophy behind De Duurzame Oplossing is rooted in physics. When the desired indoor temperature differs from the outdoor temperature, heat is lost through the walls, roof, windows, doors and floor. Heating compensates for that loss.

In summer it works the other way round: excess heat builds up, and cooling brings it down. How well the building envelope is insulated determines comfort and how much energy that comfort takes. That energy need is expressed in kilowatt-hours, and what it costs is expressed in euros.

A DDOP figure holds a thermometer against a cutaway building-block house, next to a blackboard with formulas for heat loss and a balance scale weighing coins against a heat pump. This is how the physics of a home translates into energy and cost.

Residential focus

De Duurzame Oplossing focuses specifically on homes. That's where our expertise lies, and that's where most policy questions come from.

Residential behaviour has its own complexity. One resident showers in the morning, another in the evening. Everyone cooks at a different time. Washers and dishwashers run when convenient, regardless of how much capacity is left on the grid. Peaks vary by household, by season, by family composition.

For grid operators trying to prevent congestion, and for organizations working with dynamic tariffs, that time dimension is exactly the point.

A cutaway building-block house: one resident stands by the shower, another is cooking, there is a washing machine, and outside a car is charging. Showering, cooking, washing and charging each happen at their own moment, and that timing decides when the peaks fall.

The time factor

Our methodology and calculation tools calculate every one of the 8,760 hours in a year for every individual home, from the seasonal level down to month, week, day and hour. That reveals peaks in supply and demand, how loads coincide at street level, and the effect of energy-saving measures at specific moments.

Time works in three directions:

How it was. What did an earlier measure actually achieve?
How it is now. What is the current situation, hour by hour?
How it could be. What does the next step yield, for this specific home?

That delta, the difference between now and later, broken down over 8,760 hours, gives insight for each home, neighbourhood or municipality.

The same building-block house three times side by side: before any measures, with solar panels, and with solar panels and a heat pump. Step by step, you see what each measure yields for this home.

Complementary to NTA 8800

NTA 8800 is the Dutch method for calculating the energy performance of buildings. It is laid down in the Besluit bouwwerken leefomgeving (the Dutch Buildings Decree) and forms the basis for the energy label, BENG (the requirements for nearly zero-energy buildings), EPV (the energy performance fee) and a growing number of subsidy schemes. A uniform calculation method provides comparability, a verifiable minimum standard and an objective basis for subsidies or mortgage terms.

Our methodology complements NTA 8800. NTA 8800 was designed for compliance and comparability; De Duurzame Oplossing for design questions and scenarios. Which measure works at this location, when does the peak fall, which combination yields the lowest real cost?

Together, the two give the full picture: NTA 8800 supports the business case where the law requires it, and our dynamic simulations show which measure has the greatest effect on peak load, comfort and real energy demand.

What do these insights mean for your organization?

A neighbourhood plan, a portfolio model or a modelling question. Find out how De Duurzame Oplossing helps you make better-informed decisions.

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