How is our house “behaving”?

Since we began to dream about and design our energy efficient home a few years ago, we started to monitor the temperatures we experienced in our apartment/house and so I have become very accustomed to having thermometers dotted around the house. This was a great way to start understanding the concept of comfort…what is the minimum or maximum temperature at which one is still comfortable and not feeling really cold or really hot.  

So measuring temperature (and energy consumption) in our passivhaus-inspired home is really important for us to understand how our house is “behaving”. Unfortunately, due to COVID-19 we have been unable to install the automatic monitoring system to be able to monitor energy consumption and temperature on a continuous and more precise basis. Thus, for the scientists, engineers or specialists reading this blog, our monitoring is not perfect, but it has given us a general idea over this first real month of very varied autumn temperatures.

For now, Rodrigo is measuring energy consumption daily and I have been keeping a register of morning temperatures in the living room, bedroom and the exterior. I am on temperature duty as I am the first up in the morning to make coffee, and so we have taken measurements more or less uniformly between 7 and 7:30am each day.

May has been an atypically warm autumn month in the central region of Chile, with a few days of maximum temperatures in the mid to high twenties. This has helped to heat the house during the day, but the minimum temperatures drop into single digits and this makes for rather chilly mornings. As you can see from the blue graph, the morning outside temperatures varied quite dramatically over the month (0,1°C on 13 May and 14,1°C on 27 May). Yet in the living room (orange graph), the minimum was 17°C on 22 May and the maximum was 22,7°C on 18 May. There were only 5 days where the morning temperature inside was below 19 degrees which is still comfortable enough to not even use slippers or a jersey. 

As a comparison, a friend of ours mentioned that in Santiago, he is waking up with temperatures around 11°C in the morning INSIDE his apartment. This is a marked difference to our average of 19,8°C (living) and 21,2°C (bedroom).

And when we compare to our neighbours here in Maria Pinto, we know that most of them turned on the heat at least a few weeks ago. We have yet to turn on the underfloor heating and the only change we have made is to roll back the awnings over the patio in order for the house to get full sun throughout the day.

Energy Monitoring

As I mentioned at the beginning of this post, monitoring the energy balance of the house is critical to understand how much energy is being consumed for heating/cooling. Since we moved into the house in January, Rodrigo has been monitoring energy consumption daily to build up a database and get an idea of how many solar panels we need to install for our energy needs. But for now, it is interesting to see how low our energy consumption has been over the last 4 months. We are excluding January from the analysis as we weren´t living here for the full month.

As you can see from the above graph, we have consumed less than 140 kw/hr every month and in March we only consumed 96 kw/hr.

But most people really pay very little attention to their domestic energy consumption each month and the only information that they look at on their account is the amount they need to pay. So you are probably wondering whether these numbers are good or bad, high or low. Therefore, to give you something to compare to, we have taken the energy consumption of 4 of our neighbours who have houses of similar sizes to us (around 120-140m2), similar materials (wood) and similar occupancies (2-3 people) and compared the average monthly consumption of these 4 houses with ours:

So this should give you an idea of how much lower our energy consumption is to the typical average. We have consumed between 36 and 59% less each month than our neighbours. And we still haven´t even installed the solar panels (thanks to Coronavirus) which will provide us with “free energy”, especially in the summer months.  

So all in all we are doing well and are very happy with the way our house is “behaving”. I can´t tell you how amazing it is to have such a stable level of comfort 24 hours a day 7 days a week.

Looking forward to seeing how we perform over June which is when the cold days should really set in…