How To Design Buildings That Use 90% Less Energy

[@hermannkorner3212]

I'm a great fan of these principels. However one is missing: heat storage capacity ! passive solar gains lead to rapid overheating of a well insulated home, when the thermal storage capacity is unsufficient - even in winter. I would hate to ventilate these precious gains to the outside !

[@AntonDobrevski]

Thermal mass / heat storage plays a much smaller role in Passive House projects compared to standard buildings, due to the high insulation levels. Basically, the more energy-efficient the building is, the smaller the role of thermal mass is. Therefore, thermal mass is not a leading factor in the decision-making process for Passive House projects for example when choosing between concrete and timber.

[@hermannkorner3212]

I get your point. However: good insulation and ERV only reduce external loads! Internal gains are trapped inside. This is a good thing as long as you need them; otherwise the asset becomes a liability, and heats up the building beyond the comfort threshold. Rather than bypassing the ERV or opening the windows i'd prefer to store the gains in thermal mass for use in the next cold Phase.

[@AntonDobrevski]

These principles are applicable for warm and hot climates as well. ERV still helps in hot climates because it keeps the heat outside and the colder (conditioned) air inside. During the night, when outside it's cooler, we can use night cooling or HRV bypass, which helps cool down the building and make use of the lower outside temperatures. Regarding the thermal mass - in warmer climates it's more effective but still not as effective as the night cooling/HRV bypass.

[@hermannkorner3212]

I'm with you for the summer case. My concern is overheating in winter, if you combine large southfacing windows with low thermal mass as eg SIP- panels provide. Does that show in PHI simulations?