We have had temperature and humidity data recorded in the house over the last 4 months as part of a project conducted by Anthony Mach, a passive house designer and Building Science research student at Algonquin College. The preliminary data is now available, courtesy of Anthony. What we have here is essentially the raw temperature and humidity records in two locations: one in the middle of the open-plan downstairs space (1st Floor), and the other upstairs on the landing (2nd Floor). There is a lot of analysis to be done with this data combined with other data on external temperatures, energy use and so on.
A few things to note when looking at these charts:
We were only half-moved in for most of November – we started using the kitchen sometime in the second week.
We were away from the 20th to the 30th of December, and had the HRV just ticking over, which means that the house would have had almost no internal heating. You can see the drop, but what’s remarkable is that the place still never got below 13ºC.
Once everything was back to normal and functioning properly, from early January, the temperatures in the house were generally between 17ºC (average night-time low) and 19ºC (average day time high) upstairs, with the extremes being 15.5ºC and 21ºC; and 18ºC (average night-time low) and 20.5ºC (average day time high) upstairs, with extremes of 16.5ºC and 22ºC. The difference is probably explained by a combination of the use of the extra heating downstairs, the passive solar effect from the larger windows, and generally that there is more activity downstairs for more of the time.
The humidity has generally been where you’d want it, between 40 and 50%, gradually drying out as winter goes on. Our HRV having an ERV core helps in stopping the place getting too dry.
We’ve not been posting recently because not much is happening. We’ve had and passed the electrical inspection, which means we can actually start to put in the light fittings we intend to live with (which are mainly European and Japanese and while perfectly safe, have not been submitted to Canadian inspection). Chris and Anne from New Leaf Custom Homes came round to discuss the few small things we need to do to get through the final inspection and get our official occupancy permit, which should get done over the next couple of weeks. Beyond that, we don’t have the money at this point to do anything else for a few months. So, the Japanese room, built-in shelving will have to wait, as will the solar array and home battery system.
We’ve had a few interesting and critical comments on aspects of the design from the edited reposts of earlier blog entries that are being published on the excellent Green Building Advisor site, and I’ve responded to those in the site, but the simple observable truth is that the house works. We’ve been in it since December now and even though this has been a grayer and cloudier winter than usual, which means the solar gain is less than normal, the house has still been maintaining an even interior temperature of between about 15ºC (nighttime low) and 21ºC (daytime high) without the wood or pellet stove that so many people insisted that we would need. Rainwater / snow-melt harvesting has also provided for all our water needs without any sign of getting low, although this winter we may have benefitted from the unusually uneven temperatures. Short version: whatever, we could have done differently, and indeed would do differently were we starting again, it’s all good. We already published some reflections on why we did things the way we did, last year, but I will do a more detailed post on exactly what we would change were we starting again, because that’s really what everyone else who might be considering this kind of house wants to know…
The coldest night we’ve had in the passive house so far saw the outside temperature drop to -20ºC (and that’s before we take account of wind chill). However, inside it was 15ºC when we got up, and with a couple of hours of the little room heater and the sunshine today, we’re now up to 19ºC. Plus, the place feels much warmer than this. It’s hard to describe what this means over and above physical temperature, but it’s something to do with the evenness of the temperature and the aesthetic warmth of the wood.
One other issue, apart from the Motura door seal which we discussed yesterday, is the lock on the front door. This might be passive house certified and highly insulated but the lock is essentially a metal tube which goes from one side of the door to the other, in other words a cold bridge surrounding an air leak. It might be a very small example of both, but the ice that forms on the inside of the lock when it’s as cold as it was last night, shows the truth!