This post is part of our series that shares questions we regularly receive about Passivhaus and low energy construction. We will be posting a new one every week. Explore our Blog to learn all about why designing buildings to low energy standards like Passivhaus delivers a lot more than just energy savings.
The Passivhaus standard, renowned for its ultra-energy-efficient guidelines, raises intriguing questions about heating. If these homes require minimal heating, what's the best system to choose? Let's delve into the ideal heating solutions for a Passivhaus.
Understanding Passivhaus principles:
Before discussing the best heating options, it's essential to grasp the core concepts of the Passivhaus standard. Developed in Germany, the Passivhaus design minimises a building's energy consumption by focusing on:
Thermal bridge-free design.
Mechanical ventilation with heat recovery (MVHR).
Due to these principles, Passivhaus buildings can reduce heating energy consumption by up to 90% compared to conventional buildings.
Minimal heating requirement for Passivhaus:
Given the exceptional insulation and airtightness of a Passivhaus, the heating demand is drastically reduced. In many cases, the heat generated internally from occupants, appliances, and lighting can suffice to keep the home warm during cooler periods. The sun's passive solar gain, through well-placed windows, further aids this.
So, what's the best type of heating for a Passivhaus?
Post-heating of Fresh Air: One efficient way to introduce heat into a Passivhaus is by post-heating the fresh air that comes in via the MVHR system. The incoming fresh air can be warmed by a small electric heater or a hot water coil connected to a central heating system. This method ensures that the heat is distributed uniformly throughout the home.
Underfloor Heating: Due to the even distribution of heat and the ability to run at low temperatures, underfloor heating can be an excellent choice for a Passivhaus. This system is typically combined with a heat pump, ensuring efficient energy use.
Heat Pumps: Air-source or ground-source heat pumps are becoming increasingly popular in Passivhaus designs. These systems extract heat from the outside air or ground, increasing its temperature, and then transfer it inside. Since the heating demand in a Passivhaus is minimal, heat pumps can operate very efficiently, especially when combined with underfloor heating or low-temperature radiators.
Compact Systems: These are all-in-one units that combine heating, ventilation, and hot water. Designed specifically for Passivhaus buildings, they integrate the MVHR system with a small heat pump. Compact systems provide both ventilation and the minimal heating required, making them a convenient option for smaller homes.
Wood Stoves: In some cases, residents may opt for a wood stove. However, due to the limited heating demand in a Passivhaus, such stoves would need to be very small and used infrequently.
Factors to consider:
When selecting a heating system for a Passivhaus, it's essential to consider the specific needs of the building and its occupants. Factors like local climate, availability of energy sources, budget, and personal preferences will play a role. However, always prioritise systems that operate efficiently at low temperatures.
While Passivhaus designs dramatically reduce the need for active heating, the right system can ensure optimal comfort during the coldest days. From post-heating fresh air to efficient heat pumps, several options align well with the Passivhaus philosophy. Always remember: the aim is not just warmth but achieving it in the most energy-efficient manner possible.