Passive homes are becoming more widespread in our country. And to be strict, it is not only worth that the houses are efficient, but they must also have the added value of having a Passive certification. And this is a reason to rejoice because these types of passive houses are not only good for the environment, since they have less demand and environmental impact. But they also improve comfort and health for those who live in it.
There are many points that this type of passive housing needs to meet in order to comply with the Passive standard. And for that reason it is normal to have many doubts about it. In this line, one of the questions that we hear the most in our Efficient Architecture Studio in Zaragoza, Madrid and Valencia, is whether it is possible to install a fireplace in a Passive.
To do this and first of all, it will be necessary to differentiate between the need to include a fireplace for energy reasons and how to heat the home. Or if, on the contrary, it is an aesthetic question or nostalgia for the typical homes in which there used to be a wood-burning fireplace, a Basque fireplace… And with all this we will try to answer the big question about Passive Fireplaces. Is its use compatible?
Passive fireplaces against the principle of hermeticity?
This issue, the difference between functional and aesthetic fireplaces, is essential in a Passive. Especially to see if it is compatible or not. And it is that most chimneys, especially the best known, have a flue or duct to the roof through which the smoke comes out of the house. This point at the same time allows the free entry and exit of the air inside the house, without filtering or air conditioning. Which goes directly against the concept of hermeticity of a Passive house.
If the need for a fireplace is due to wanting to heat the home using this type of boiler, it is important to say that in a Passive home there are better means for it. And it is that in the end we are talking about very well insulated and hermetic houses. Both because of the type of construction and because of its weakest points in doors and windows. In which the energy demand is very low and therefore very little powerful equipment is needed, which we are interested in being as efficient as possible. For this reason, aerothermal energy using underfloor heating or fan coils has much greater advantages in this type of efficient house.
Types of Passive fireplaces
Well, depending on whether you are looking for more the aesthetics of a fireplace in our passive house, but air conditioning it in the most efficient way. Or if, on the other hand, the way to air-condition the house must be through a fireplace, we have the following options to include them in our Passive house.
1. Pellet fireplaces
Although we want to resort to alternative methods, we can install pellet boilers. But only if it is outside the thermal envelope, for example in the garage, and in that case we lose the aesthetic component of the fireplace at home. The other alternative would be to resort to a sealed pellet stove. It is necessary to choose low-power models because for the demands that this type of housing presents, very powerful models are not needed. Otherwise they will generate excessive heat and consumption. Although both options are less efficient and require more maintenance when charging. The sealed pellet stove can add an aesthetic value to the home.
2. Bioethanol fireplaces
Bioethanol fireplaces or stoves in a Passive home are a perfect aesthetic solution. Visually we have the sensation and aesthetics of a conventional fireplace, but with an installation system that does not harm the airtightness of the house.
They can be free-standing or installed embedded in furniture or plasterboard walls depending on the style sought. In addition, maintenance is punctual, to fill the chimney with bioalcohol, which is the fuel they use. Some heat is generated, controlled, but without smoke or dirt.
By themselves they are not capable of generating enough heat for the entire house, leaving their radius of action reduced to the area where they are installed. Their reason for being is more for an aesthetic issue and they perfectly fulfill their function in a Passive House.
3. Electric fireplaces
Along the same lines as bioethanol fireplaces, electric fireplaces are a plus compared to these for power, design and price.
On an aesthetic level, electric fireplaces create a fictitious fire from the LED lighting they carry, which in some cases is very realistic and provides an aesthetic value similar to the real one. With many more advantages such as energy efficiency and absence of maintenance.
Most electric fireplaces also generate heat through an electrical resistance. That although it is greater than in bioethanol fireplaces, it is still not enough to heat the entire house. In any case, through this use, consumption can be triggered, so an aerothermal system for air conditioning in the home continues to be much more efficient. Leaving the electric fireplace as a purely aesthetic use.
Alternatives to fireplaces in a passive house
For all that has been said, it seems sensible to opt for alternative air conditioning systems to the fireplaces in our Passive. Especially an aerothermal boiler using underfloor heating and/or fan coils. Although a draft fireplace is not possible in a passive house, aerothermal energy is more efficient and requires much less maintenance than a sealed pellet fireplace. Because aerothermal energy can solve DHW, heating and cooling with the same system and thus we achieve much better performance and lower consumption in our Passive.
Conclusion on the chimneys in a passive house
We have explained, on the one hand, that a chimney system with direct access to the outside is not possible, since it would impair the hermeticity of our Passive. As well as having so little energy demand, there are other systems such as aerothermal energy that are much more efficient for the air conditioning of our home.
And if you want to include a fireplace in your home for aesthetic reasons, it will be better to choose between a bioethanol fireplace or an electric fireplace. That they will perfectly fulfill the aesthetic function of the fireplaces, at the same time that they guarantee that our Passive works correctly. Ensuring very low energy consumption and environmental impact, at the same time as great comfort inside.