Furnace Buying Guide
A quick guide to strategic product selection
Energy Source
Typically, you do not have much of a choice when it comes to choosing the energy source that will power your home's heating unit. This usually depends on the energy source available in your neighborhood, natural gas, propane, oil, electricity. That being said, there are renewable energy source options to consider even if they may not seem readily available. These include but are not limited to sun, wind and geothermal.
► Click here to learn more about various heating system types. Learn how they work, what their advantages are, how cost-effective and energy-efficient they are, and what their environmental impacts are.
AFUE Rating
Furnace efficiency is measured using the Annual Fuel Utilization Efficiency (AFUE) rating. AFUE is the ratio of heat output compared to total energy consumed. In other words, AFUE measures how well a unit converts energy into heat for your home. The higher the AFUE, the more efficient the furnace. An AFUE of 90% for example means that 90% of the energy in the fuel becomes heat and the other 10% escapes/is wasted. The AFUE rating does not include heat loss associated with the duct system or piping, which can be as much as 35%.
ENERGY STAR Label
Earning the ENERGY STAR label means products meet strict energy efficiency guidelines set by the U.S. EPA and the Department of Energy. ENERGY STAR qualified oil and gas furnaces have AFUE ratings of 85% and 90%, or greater, making them up to 15% more efficient than standard models.
Proper size
Like with all HVAC equipment, the most common sizing mistake with furnaces is in oversizing. This not only makes the new system more expensive to install, but also forces it to operate inefficiently, break down more often, and cost more to operate. Oversized heating equipment also can create uncomfortable and large temperature swings in the house.
It is your contractor's job to perform the correct sizing calculation for the building. Many contractors only check the "nameplate" (the label on the unit that has the Btu per hour output among other things) of the existing system and then will try and sell you one just like it, or even worse, one that's larger. This is a not a correct sizing method and not in your best interest.
Correctly sizing a heating (and cooling) system includes factoring-in the following:
- Local climate
- Size, shape, and orientation of the house
- Insulation levels
- Window area, location, and type
- Air infiltration rates
- Number and ages of occupants
- Occupant comfort preferences
Buy local
To reduce carbon emissions associated with product transportation and to support your local economy, we encourage you to buy your boiler from a local manufacturer.
Questions? Feedback?
Visit our Forum to ask questions and share your thoughts about innovative, energy-efficient home heating products.
