Central Heating: Not Just Hot Air
Pre-Heating: Before You Upgrade
Did you know that between 25% to 40% of your heating system’s output may be escaping to the outside through cracks and other openings in the home?1 Before upgrading to a more efficient furnace, minimize your operating costs. By insulating, weather-stripping, and improving your windows first, you may be able to upgrade to a smaller, less expensive furnace.
Planning Pays: Heating Efficiency
Investing in space heating systems is an expensive and long-term decision. First, determine whether (and where) your home loses heat through its building shell. Next, improve your existing heating system’s efficiency. Then, if you buy a new heating system, consider your climate, the size of your home, your budget, and local utility and fuel costs. Weigh the system’s initial purchase price against its long term operating costs.
Hot Air vs. Hot Water: Furnaces & Boilers
Furnaces and boilers are the most common types of heating systems. The main difference is that furnaces burn fuel to heat air distributed through ducts, while boilers burn fuel to heat water circulated to warm the air in individual spaces. Controls, like thermostats and valves, turn the heating system on and off to maintain comfortable indoor temperatures. In addition to space heating, boilers can also be used to heat your hot water supply, but can be slow to warm up. Unlike ducted systems, boilers can’t filter air or ventilate your home. Furnaces have the additional advantage of using the same air ducts as your central A/C. Highly efficient models will cost more to purchase (and possibly install), but they will cost less to operate over their 10 to 20 year lifetime.2
Heat Pumps: Smart for All Seasons
Heat pumps are economical and energy efficient for both heating and cooling. They extract heat from one place and transfer it to another. Residential heat pumps are either air-source systems, which draw heat from the air, or ground source systems, which draw heat from the ground or ground water. Both systems use electricity, but they are highly efficient because more than 3 times the energy they consume is converted into heating or cooling output.3
In cold weather, an air source heat pump removes warm air from outside the home and transfers it inside. In warm weather, the process can be reversed and the heat pump works like an air conditioner.
Ground source heat pumps take heat from underground. They require more space and are better suited for homes with large yards. Purchase and installation is costly but ground source systems have best operational savings in regions with extreme heating and cooling loads and generally higher energy bills.4
Rain or Shine: Active Solar Heating
Active solar systems capture and convert the sun’s energy, but also require power for supplemental electrical equipment like pumps or fans to circulate either liquid or air heated by solar. Liquid systems, like boilers, are available in models capable of heating both room spaces and water, while hot-air systems work much like furnaces.5
Solar heating systems are often designed to work together with other heating systems for better flexibility. An active system may not meet all your heating needs, especially in cold, cloudy climates where a backup heating system is required. An active solar heating system may still make sense in regions with longer cold-weather seasons, many sunny days, and above-average utility and fuel prices. Active solar heating systems cost from $5,000 to $18,000, but one room solar heaters are available for about $800.6 However, the operational savings can be exceptional. To learn more, contact an experienced solar heating designer, to see if active solar is right for you.
Size Matters: Equipment & Installation
Properly sized equipment and installation maximizes the benefits of new or modified heating systems. Oversized systems tend to turn on and off more frequently and accumulate moisture, which can damage the unit over time, while undersized systems won’t adequately heat the home. When requesting a size and installation quote, choose a contractor that follows ASHRAE and Air Conditioning Contractors of America guidelines. This will help ensure that factors including climate, the size and orientation of your home, any heat loss from your building shell, and your lifestyles are considered in the contractor’s calculations for the best fit.
Content in part adapted with permission from Rocky Mountain Institute’s Home Energy Briefs.
Before you shop for efficiency upgrades, visit the Central Heating Buyer’s Guide for easy facts and figures that can help you choose the best equipment and materials for your home, needs and budget.
 Yardi, Ramola, Wang, K., Smith, A. (2004). Home Energy Briefs: #4 Space Heating. Rocky Mountain Institute. Retrieved September 28, 2012 from http://www.rmi.org/rmi/pid217. (p.1)
 Yardi, Ramola, Wang, K., Smith, A. (2004). Home Energy Briefs: #4 Space Heating. Rocky Mountain Institute. Retrieved September 28, 2012, from http://www.rmi.org/rmi/pid217. (p.3)
 Yardi, Ramola, Wang, K., Smith, A. (2004). Home Energy Briefs: #4 Space Heating. Rocky Mountain Institute. Retrieved September 28, 2012, from http://www.rmi.org/rmi/pid217. (p.5);
 Yardi, Ramola, Wang, K., Smith, A. (2004). Home Energy Briefs: #4 Space Heating. Rocky Mountain Institute. Retrieved September 28, 2012, from http://www.rmi.org/rmi/pid217. (p.5-6)
[6&7] Ibid (p.6)
This program is funded by California utility customers and administered by Southern California Edison under the auspices of the California Public Utilities Commission.