How I Built this Energy Efficient House for Under €100,000

Interview with the CEO of Passive Sills, Patrick J. Beausang

What inspired you at the beginning to build an energy efficient house?

I wanted to the traditional house but not in a traditional way. I had loads of time but not as much money. So I used my time to research how to go about it.

I learned that there was no real reason for the way we build traditionally and that the more unusual and modern ways of doing them could be far more suitable. The biggest reason for building the way we do is because that is what we always do. In 2019, one of my children won an award at the BT Young Scientist. The first line in their introduction was “Imagine if we put 100 of the world’s best scientists into a room and told them, ‘design me a roof.’ The ideas they would come up with would blow our minds. But then imagine someone at the back of the roof stood up and said, ‘why don’t we nail 500+ flat stones to the roof with copper nails?’ You would be looking around thinking, ‘who invited this guy,’ but that’s what we do. That’s how we build our roofs.” The only reason we build roofs this way is because that’s how it’s done. That’s how my father and his father, and his father did it. This went into many different sections of the building industry including the structure, foundations, etc. Everyone was telling me “Cavity wall construction is the only way to do it” and “Don’t bother with that insulated foundation, it’s just a waste of money” when in reality, it was the exact opposite.

Another factor in my decision to build passive was the fact that I wanted a comfortable home for me and my family. I have a daughter who has some health needs and it has been proven that passive houses lead to better health for those who live in them. This is usually due to the lack of mold, condensation, cold, etc that occurs in traditionally built homes. I can attest that my daughter’s health has improved since we moved into this house*

*Please note, moving into a passive home was not the only reason for the improvement in his daughter’s health.

What problems did you face through this process

Trying to eliminate cold bridging. Window Sills, door thresholds, they were all huge problem areas when trying to build a traditional-looking home in a nontraditional way. As I looked into solutions I found very little until I came across Passive building. It sorted out all the problems I was having.

Another issue was money. I didn’t have very much of it and everything I needed was needed a lot of money. I didn’t want to take out a mortgage so I had to put my thinking cap on. What solution did that cap come up with? DoneDeal. No, I’m not kidding, the steel frame for my walls, my timber truss for my roof, and the blocks of polystyrene to put in my foundation. They were all found on DoneDeal. I checked the DIY section of the website every day and was patient knowing that eventually, what I needed would come up. My best find in my opinion was the bathroom pods. These were hotel bathroom pods that were pre-made for the construction of the hotel. They had too many do they put two of the pods on DoneDeal. I bought them for €800 each and all I had to do was drop them into my house with a crane and connect plumbing and electrical.

How did you learn about passive building?

Because I had so much time I did a lot of research. During this research, I came across the passive house institute of Germany. From the first time I heard about Passive house I found the concept absolutely fascinating and from that point forward any article I saw, or video clip I watched, I used it as an opportunity to educate myself on principles of energy-efficient building. One by one, I started to learn about each of these principles. Over many years I attended and always found myself being drawn to products in these fields.

What would you recommend to first time builders trying to build the best house they can for what they can afford?

Many will say there are more, but I believe there are 5 Fundamentals of building. These as such be your testaments.

The first three are to do with the materials you use to build the house

The first one is insulation. This is hugely important. The structure is the structure, but you have to get sufficient insulation into it to help with the elimination of cold bridging throughout your home.

The second one is airtightness. Airtightness can make an incredible difference in the performance of your home. “It’s astronomical.” It also links into moisture management but we will talk about that later

The third one is eliminating cold bridging. The more you make your house energy-efficient and the warmer you make your home, the more critical cold bridging becomes in your home. So in a traditional building where you see one of the major problem areas for cold bridging, and a place I couldn’t find an acceptable solution was through your window sill. I couldn’t find a traditional-looking window sill that did the same as what a little bit of metal folded over some insulation, and even then, that insulation didn’t do a lot. I wanted something that looked like every other farmhouse and when I started researching it there was nothing there. This leads me to develop the Passive Sill. A lightweight, thermally efficient, window sill that looked just like a traditional window sill but completely eliminated the cold bridging. This was the first product we ever produced and is still one of, if not, our top sellers. It eliminates cold bridging because if you think of it the window sills were originally bridging from the outer leaf to the inner leaf and the window sitting on top of it. So you just have a big concrete bridge at the back of your window. If you’re getting mold growth or condensation, stick a digital thermometer at the back of it and I guarantee you that during the winter when you’re getting condensation, that point is only reaching 14 degrees celsius. If the temperature drops below 14 degrees celsius you will get condensation, if it drops below 12, you will get mold growth. They are the key areas when it comes to the fabric of the house.

The fourth one is orientation. If you are building a house and all your windows are south facing you will have a positive solar gain in the winter however, during the summer, the sun is very high in the sky and if you have any bit of an overhang, you won’t get much solar gain at all. So you will have solar gain when you want it in the winter and very little solar gain in the winter when you don’t. Now, it’s a bigger problem for energy-efficient houses with overheating rather than being cold because we’re building our house more like a thermal flask compared to the traditional lunch box way we have been. East and west-facing glass will lead to a lot of excessive heat and overheating in your home. So even if you’re building a house in the morning and you’re on the left-hand side of the road with the front of the house facing the road, I would put most of your living at the back of the house, have where you will be doing your most living south-facing, because having a house south facing is the most energy-efficient way to build as well as being conscious of excessive glass use in the house

Lastly, ventilation. We’ve built an air-tight house which is all covered in the materials of the house but now we need to get air in. Some of the most common things I hear about Passive Building are “You can’t open a window in a passive house” and “If your heat recovery system fails you have no air in your house” this is a load of rubbish. If the power goes out to the heat recovery system you can open the window until it’s fixed and it will perform like any other house. You may not be getting heat recovery but you will be getting efficient ventilation into your home. Air is like water, it will stagnant and stagnant air in your home will problems such as moisture and condensation which causes health issues. You will only lose a small amount of energy efficiency if you open the windows in your home.