HOT UPSTAIRS SOLUTION
An ozone generator will get rid of bad odours, such as lingering rat stench
Q Why aren’t our skylights allowing hot air upstairs to leave the house? When the air conditioning is on and the second floor is still too warm, we open the skylights (usually in the evening) an inch or two as you’ve advised in previous articles. But all we notice is more warm air coming in! We cannot get the second floor to cool down. Should we have the skylights open during the day on hot and humid days? Just open them at night? How long after opening should we feel the “cooling” effect? Maybe we just haven’t been patient enough?
A
It sounds like you might have something causing negative air pressure in your house, perhaps an exhaust fan that’s running a lot or an unbalanced heat recovery ventilator (HRV). If sufficient air is being pushed out of the house by an appliance like these, then outside air needs to flow back in somewhere to compensate.
Here’s an exercise: shut off all fans and the AC, then open the skylights a couple of inches on a day that’s calm but hot. At the same time, open a window or two downstairs and see what happens to air flow. In every house I’ve seen with upper-storey skylights (including my own), there’s a kind of chimney effect created. You can feel air moving up and out of the house as the hot air leaves upstairs. It happens right away, too. In fact, in my case, the skylights on the third floor allow air movement up and out of the house that you can feel on all levels.
If air is flowing out of the skylights as it should with all the appliances off, then one of those appliances is to blame for the previous reverse flow. If your heat recovery ventilator (HRV) is pushing out more air than it’s drawing in, this could certainly be the cause. Unbalanced HRVS are quite common. All properly installed HRVS include some kind of balancing valve on the ducts that connect to the unit. Reducing air flow through the incoming duct could solve your problem.
ELIMINATING BAD ODOURS
Q Do you know of any way to get rid of the smell of rats? My daughter bought a house in an old Toronto neighbourhood and rats have been living in the frame walls of the finished basement for years. The walls have been stripped but the smell is still strong.
A
A small, portable electric appliance called an ozone generator is the industry standard for eliminating odours in restoration situations. I have one at my place and it works really well. Ozone is an unstable oxygen molecule made of three oxygen atoms instead of the usual two. This extra oxygen atom makes ozone a powerful oxidizer, chemically breaking down the odour-causing compounds.
Expect to pay at least a couple of hundred dollars for an effective ozone generator, and look for a model rated to handle the square footage of area involved. I use my ozone generator periodically around houses and even in vehicles. It keeps everything quite odour-free. Ozone treatments do need to be done with safety in mind so follow the instruction manual of any machine you buy.
When it comes time to refinish the basement, don’t get in a hurry. Ideally your daughter should observe the basement for at least a year to make sure there are no water leaks. Also, I always recommend against any kind of fibre-based insulation in basements. There are many ways big mistakes can be made when finishing a basement, and many of these mistakes are currently made all the time even today. I’ve got a detailed online video course on how to finish basements properly at baileylineroad.com and it’s currently free until October. Steve Maxwell teaches hundreds of people each month online with his home improvement courses. Visit Steve online at Baileylineroad.com