Living in Elgin, Illinois, the weather is constantly a consideration; My nice friend and I don’t buy tickets to interesting events or concerts between the months of December & April because of the potential for blizzard conditions & icy roads. My nice friend and I need a wardrobe that includes heavy boots, wool coat, gloves & hats plus shorts & tank tops, and it’s helpful to drive a four-wheel-drive vehicle & necessary to own snow shovels & ice scrapers, then over the winter, the temperature is consistently below frosty & officially dips below zero, and the snow can accumulate in feet overnight & the wind chill can be dangerous, however during Springtime & fall, my pal and I expect thunderstorms, high winds & heavy rainfall. There can be power outages & flooding, while summers are officially short, they are hot & especially humid. I usually switch from running the boiler to starting up the air conditioner with no cut in-between. There is seldom an occasion to open the windows & welcome in fresh air! Because of the expense of heating & cooling, keeping a tightly sealed thermal envelope is a priority. I’ve caulked, insulated & weatherstripped to prevent energy waste, however, the lack of natural ventilation creates concerns with indoor air quality, but contaminants get trapped indoors, circulated throughout the condo & can lead to health risks. The air starts to feel stale & stuffy. When I mentioned these concerns to an Heating, Ventilation plus A/C supplier in Elgin, he suggested the installation of a heat recovery ventilator. An HRV brings in a steady supply of fresh air to upgrade the stale air. By using the outgoing air to preheat the incoming air in the winter, it lessens demands on the boiler.