What Is Heat Loss?

We live in the coldest capital city in the world. That is why, when it comes to building insulation, we are ahead of most countries. But that does not mean what we have is enough. If we increase building insulation by just 30%, we can begin to see truly remarkable differences in performance.

If we insulate a building sufficiently and make it highly airtight, we can go without heating for almost the entire year, except during the coldest months of December and January. Why? Here comes the most interesting part.

We generate a tremendous amount of heat in our daily lives: cooking, ironing clothes, watching TV, and so on. Once heat loss is reduced to a minimum, the amount of heat generated by these everyday activities becomes significant enough to meet a household’s heating needs.

However, there is one critically important factor to consider. If there is no air leakage at all, indoor air will become polluted very quickly. So, how do we ventilate the space?

If we rely on traditional ventilation methods or simply open the windows, all the value created by investing in high-quality insulation will be lost. Therefore, if we aim for the highest possible insulation performance, an Energy Recovery Ventilation (ERV) system must be planned and installed as an integral part of the building.

An ERV system can recover up to 90–95% of the heat and moisture from indoor air, helping preserve both indoor warmth and humidity.

A Passive House works on exactly this principle.