Air exchangers work but study up on them


By CCHRC StaffQ: I understand it is important to get fresh air into my house, but exchanging air in my home means the warm air is going out and cold air is coming in. I pay quite a bit to heat my home and reheat all that air coming in. Can air exchangers help to solve this problem?There are several types of air exchangers on the market, but not all of them capture heat from the outgoing stale air.Q: When should I start plugging in my vehicle?

The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.

Commercially available exterior wall vents combined with a fan designed to operated all the time will provide fresh air for a home.

These devices are the least expensive, but provide no heat recovery feature.

A heat recovery ventilator (HRV) is a more expensive device that has a heat exchanger inside, where the air flowing out of the home passes by the air flowing into the home, without mixing the two. As the warm air moves out, it transfers some of its heat to the cold air moving in.

The heat recovered by this process is in the 60 to 75 percent range, which is significant because any amount of heat that is recovered represents air that the homeowner does not have to pay to reheat.

As the cost of fuel increases, this savings will be more significant.

An energy recovery ventilator recovers heat and moisture as well. Unfortunately, these systems cannot be used in the Fairbanks area because extremely cold air will freeze the device.

Many Interior Alaska residents are retrofitting their homes now.

Adding insulation and tightening a house makes ensuring you have good indoor air quality more important than ever. Insulating a home will conserve heat and adding an air-exchanging device will clean the air.

But only an air exchanger with a heat recovery option will do both.

Be sure to consult with a licensed professional to help design and or install any ventilation system.

Many of us will start plugging in our vehicle right away when it gets cold but plugging in will have an unfortunate affect on our electric bill.

The Alaska Department of Environmental Conservation provides the rule of thumb: plug in for at least a couple hours before starting the vehicle when it is 20°F or colder.

At that temperature, you can get by plugging in for less time, and as it gets colder you need to plug in for progressively longer.

If you find you need to leave your car plugged in substantially longer than these guidelines before it starts smoothly, then you car may need maintenance.

Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at can also call the CCHRC at (907) 457-3454.