Sustainable Living: Heat Your Home Efficiently This Winter

MERV: Minimum Efficiency Reporting Values
Photograph provided by MGE

If you want to take a bite out of your energy use this winter, it makes sense to attack one of your home's biggest energy users: heating.

The furnace is a good place to start. Regular maintenance helps keep it energy efficient, safe, and operating optimally. A good way to make sure your furnace is in top shape is to schedule a professional tune-up every other year. The technician will clean, inspect, and test your furnace. You also can ask for a furnace efficiency analysis. This can help you gauge when it may be time to replace your furnace with a more efficient model.

All Filters Are Not the Same
Clogged filters can inhibit airflow, causing your furnace to work harder and use more energy. During heating season, check your filter monthly, and clean or replace it when it’s dirty. This will help manage energy use and enhance air quality.

When shopping for new filters, you may be tempted to buy the most inexpensive filters on the shelf, but you should consider the MERV rating. This industry-standard rating system was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). It helps determine a filter's efficiency, effectiveness, and what it can capture and remove from the air.

ASHRAE rates filters from MERV 1 to MERV 17. The rating indicates the size and type of particles a filter can trap. This includes dust, bacteria, gases, viruses, and other contaminants in the air. The higher the MERV, the finer filtration the filter provides. The Environmental Protection Agency recommends at least MERV 13 for most indoor spaces.

MERV 8 and MERV 13 are popular filter ratings. A MERV 8 filter is 20 percent efficient at trapping particles that are between one and three micrometers. In comparison, a MERV 13 filter is at least 85 percent efficient at capturing particles of that same size. It can be helpful to consider the kinds of particles that filters with these two ratings can capture.

• MERV 8: Lint, dust, pollen, and mold spores.

• MERV 13: All those listed for MERV 8 plus pet dander, smoke, smog, particles from coughing/sneezing, and virus carriers.

Don't Forget the Fireplace
A fireplace is another way we can help keep a room warm. It's important to make sure this feature is energy efficient.

• Get your chimney cleaned. Burning certain types of wood can cause soot to accumulate in your chimney, making your fireplace unsafe and inefficient.

• Check the flue for cracks and ensure liners are intact. This is especially important if you have not had a recent home inspection.

• Check the seal on the damper. It should be snug. When not using the fireplace, close the damper. An open damper acts like a large hole that pulls hot air out through the chimney; however, if you have a continuously burning pilot light, the damper must stay open slightly to allow combustion byproduct to move up and out of your home via the chimney.

If you are installing a new fireplace, consider opting for a direct-vent model. Direct-vent fireplaces are more efficient than traditional fireplaces, which lose a significant amount of heat due to warm air rising out of the chimney. Direct-vent models also offer air quality and safety benefits.

If you’re retrofitting an existing fireplace, opt for a unit with an airtight door and a blower. The more airtight the door, the less heat that is wasted going up the chimney and the more heat you will get from the fireplace. A blower is important because it moves hot air across the top of the fireplace and into your room.

Remember to take steps to reduce heat loss even if you don't use your fireplace.

• Plug and seal the chimney flue to keep drafts out, as long as the pilot light is not on.

• Install a heat exchanger to draw in cool air from your home, heat it, and then disperse it back into your living space. Some models are mounted to the top of the fireplace opening. Others fit within your firebox.

Other Tips for Heating Efficiency
• Get your ducts cleaned. Dust and other debris accumulate in your ductwork over time. This slows down the movement of air and reduces the efficiency of your heating system. If you can access the ductwork in spaces like the attic or a crawl space, apply rated tape along the seams. This will help with heat distribution and the overall efficiency of the system by reducing leakage from the ductwork.

• Clean warm air registers, baseboard heaters, and radiators as needed. Make sure they are not blocked by furniture or drapes.

• If your home has high and low vent returns, open low vents and close top vents to draw cold air through the return registers so the furnace can heat it.

Now that you've taken steps to improve heating efficiency and air quality in your home, have you considered testing for radon? This colorless, odorless gas is produced naturally from a breakdown of uranium in soil, water, and rock. High levels can be dangerous. Fall and winter are the best time for radon testing because your home is closed up. Contact a professional to set up a test or consider a do-it-yourself test kit, available at most hardware stores.

Ask the Experts
MGE is available to answer your questions and provide tips on heating your home efficiently this winter.

• MGE Home Energy Line: MGE's energy experts are available between 8:00 a.m. and 4:30 p.m. Monday through Friday. Call 608.252.7117 or send an email to .

• You also can get more energy-efficiency tips online at and .