In the north, we seal up our homes to stop cold drafts and save money on heating. All our windows and doors are tight with gaskets and levers designed to make them as impervious as it is possible to be in the cold north wind when the temperatures drop to -40C (-40F). One of the unfortunate consequences of our eternal quest to keep out the cold is the air in the house gets stale. I suppose we could just open a window when it does, but then you have the cold draft, you have to recall when to open and when to close. Canadians generally get around this nuisance by installing a fresh air intake from the outside into our furnace intake.
After we got all the new windows installed, I noticed three new problems.
1) My allergies acted up when the house was closed. I am especially allergic to house dust and dust mites. While I am not allergic to my cat and dog, they certainly contribute to the dust in the place.
2) Our new windows were constantly wet with condensation whenever the house was closed up. Even with a dehumidifier running, the windows got so wet they just dripped and I was left with puddles to mop up on the window sills. When it got really cold, the neighbours watching our house complained of ice build up on our screen doors.
3) When we went to bed, I could often smell a funny sooty odour, an old soot smell, which would immediately go away if I opened the bedroom window a crack. We were creating a negative pressure situation in our tiny house and air was coming in where it could, including down the old wood stove chimney.
And then there was the radon issue. We bought one of those radon kits from Amazon to test our tiny house. The kits are really easy to do. You order the inexpensive little kit, put the detector in a main floor bedroom and leave it for a few months. You ship it off to the manufacture and about a month later you get a report back. Our little house came back at 176 becquerels per cubic metre. By Canadian standards anything under 200 is considered safe and about 200 you should consider minor mitigation and above 500 is serious business and you should move out until it is fixed. The best way to increase your radon is to have your house in a negative pressure situation. The radon gas gets sucked in. If you house doesn’t get into a negative pressure state, the radon mostly stays in the ground where it belongs. Now technically 176 becquerels per cubic metre is “safe” but there really is no safe minimum when it comes to radon. Less is always better. Another reason to be concerned about that soot smell.
It’s September now, and necessary to keep the house closed up at night because the temperatures are dropping to near freezing. We are not yet using the furnace because the house holds enough heat from the daytime and from cooking to be warm overnight. We started having that nasty musty smell and the soot smell return overnight and the windows were wet each morning with condensation.
Last fall, we had a furnace guy come in to add ducts so some heat went into the basement. He pointed out we had no fresh air intake and he said it would make the air stale and cause our windows to fog up. He offered to add one for us for $850. We were about to head south for the winter so we said we’d get back to him in the spring. We left a bunch of messages and he never called back. His company had a big contract installing new houses on a nearby reserve and he was too busy with that to accommodate us. (This is common in a rural setting.)
In the meantime, I was busy researching fresh air intakes. Most of the pages about fresh air intakes are about selling you a particular type but I did learn how they function. The majority of them work by having little electric fans that kick in when the furnace goes on. They have a filter inside and flaps and such, many that need maintenance. Because our house is so very small, we needed something that would work when I ran the kitchen fan or the bathroom fan even if the furnace did not come on. Running the bathroom fan is enough to create that negative air pressure. There are barometric additions to the fancier fresh air intake that keep the air pressure even no matter what. They were more expensive, much more. We also use electric heat and we don’t have a central air conditioner so a lot of stuff about code just does not even apply. While we don’t have a wood stove hooked up due to insurance issues, we do want to be able to hook it up again and use it if we were to have one of those infamous multiday blizzards with a prolonged power outage that are a once every ten year event out here in the boonies. We will really need a passive system if such a blizzard happens.
During my search, I found a relatively cheap made in Canada solution. It was ingeniously simple in design and struck me right away as so very sensible. The company is called Plusaire. It’s not the right system for all houses. It does not have a heat recovery capacity. Therefore, it does slightly increase heating costs. Because of that, in our insane drive to decarbonize the planet, that means it does not meet “code” in Ontario. I calculated how much time it would require to pay off the incredibly expensive 100% heat recovery units out there versus the increased heating cost this little lovely would likely cost me. I should live so long! The Plusaire unit needs no maintenance, filters, has almost no moving parts and there’s nothing to break down. We heat with “green” hydro electric power and I don’t believe in this whole decarbonization nonsense in any case. I decided screw the Ontario code. I don’t live in Ontario and this unit suits our needs and our lifestyle in our 480 square foot (not up to code but grandfathered in) house perfectly. I ordered it. Your mileage may vary.
Installation was actually easy. The unit came with an installation kit and instructions. I was able to install it myself after a few questions for another furnace guy who was also too busy to do the install but happy to share advice over a beer I bought him while we had a game of pool. (He won, barely. This is another way things often work in a small town.) I bought and learned to use tin snips. I read up on how to properly use the flexible ducts the unit came with. I broke the task into five steps. 1) Cut a hole through the wall of the house to install the outside intake. (Hubby dearest assisted.) 2) Mount the unit. (Hubby dearest provided some superior male intellect for me because I am just not strong enough to hold up the box and put in the screws.) 3) Install the big connector to the intake vent. 4) Install the little connector to the warm air output vent. 5) Tighten up all the flexible duct work, make sure there are no kinks and sags, put in supports, cut off excess in the flexible duct work, and use the provided roll of aluminum tape on all the places the directions said to. By spreading it all out over five days, it wasn’t quite so daunting. It’s a good thing I don’t try to get paid by the hour because I spent about three hours each day, mostly contemplating the best way to do it and double checking the instructions and rereading on line blogs. I will need to fiddle with the damper as the seasons change. I wrote the details of that right on the metal box in permanent felt pen just in case I lose the paper with the instructions.
After the first day when fresh air was now coming into the basement, I noticed an immediate improvement in the smell down there. The musty odour I was accustomed to was gone. After I got the connection made to the furnace intake, the freshness went through the entire house even with the duct work still sagging and kinked. We no longer need to leave the bedroom window open a crack overnight to keep the soot smell (and the radon) away. And best of all, our problem with the dehumidifier running constantly and still waking up to find the windows and the screen doors fogged up is gone, completely gone. Will this continue through to -40C when the furnace runs a lot? We’ll see. Will we lose so much heat with this passive system without heat recovery that we decide not to keep using it? Maybe. We’ll find out soon enough. Because when you live in Manitoba…