The principles behind air conditioning have a myriad of applications; long time followers of the blog will know that they were originally designed as dehumidifiers, and that the same logic that allows air conditioning to cool your home is used in refrigeration systems. Blog regulars will also be aware of the principles behind air conditioning, but for those of you who are new, here are the basics of what you need to know: hot air is shipped outside of the house, while cool air is vented inside. If you’ve ever felt the outside of an air conditioning system or a fridge, you know how hot they can get, so what if we were to reverse the cycle and vent hot air in and cold air out?
What would happen is the creation of a heat pump. Heat pumps use the same principle as air conditioners; refrigerant that changes state from gas to liquid because of compression and expansion, the change in states allowing the refrigerant to absorb and emit heat. Heat pumps are particularly useful for a variety of reasons; there are dual mode heat pumps that switch from hot to cold, and they consume less energy than your average furnace. All of that sounds pretty amazing, so why aren’t heat pumps used instead of furnaces all over the country?
The answer to that lies in what most would consider a comfortable room temperature. Consider how your air conditioner cools your home; if the temperature outside is 30 degrees, and you want your home to be 20 degrees, you only need to cool your home a total of 10 degrees. Conversely, if you were using a heat pump, it stands to reason that heating your home 10 degrees would take about the same amount of energy; when it’s 10 degrees outside, or really any temperature above freezing, heat pumps can be used quite effectively.
The trouble pops up during our cold Winnipeg winters; as you probably know, it can easily hit -30 on our colder days. Consider how much you need to heat your house in order to be comfortable in those conditions; there’s going to be a 50 degree difference between the weather outside and the temperature you want in your house. That means you’ll need some more heavy duty heating, and that’s where a gas or electric furnace will come in handy.
There are still efficiencies to be found with a heat pump, though; when the weather is above 0, a heat pump can warm your home with fewer energy costs than a furnace. One potential solution is to use a dual heat-pump/furnace setup; the heat pump for when it’s above 0, and the furnace for when it falls below. Professional heating contractors will be able to go over your options with you, and show you what your potential energy savings are with each setup relative to the cost of solution. A heat pump/air conditioner may very well be worth your while!