Energy Saving Devices

Archive for January, 2010

Older space conditioning systems (more than 10 years old) are often unreliable and much less efficient than a modern system. When it’s time for a new replacement, choosing one of the correct size (heating and/or cooling output) is critical to getting the best efficiency, comfort, and lowest maintenance and operating costs over the life of the new system. Some national surveys have determined that well over half of all HVAC contractors do not size heating and cooling systems correctly.

The most common sizing mistake 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 often creates uncomfortable and large temperature swings in the house. Oversized air conditioners (and heat pumps) do not run long enough to dehumidify the air, which results in the “clammy” feeling and unhealthy mold growth in many air-conditioned houses.

Source: EERE, Department of Energy

Electric resistance heating, also called electric baseboard heating, is the cheapest to install and the most expensive to operate, as it is the least efficient source of heat. Unfortunately, upgrading to ducted systems, as discussed below, will involve a significant expense for ducting. Another option is to switch to a hot water baseboard system. Baseboard heaters can probably replace electric resistance baseboards in the same location, but will still require extensive plumbing.

Steam systems are generally less efficient than hot water heating systems, but the efficiency gain of upgrading to hot water is probably not worth the expense; it would be better instead to upgrade or replace your boiler. However, it is sometimes possible to convert existing steam distribution pipes to hot water heating, which reduces the cost of the system to the cost of the boiler, the baseboard heaters, and the installation labor. This is generally only feasible in newer two-pipe steam systems (that is, systems in which two pipes go to each radiator, one for the steam and one for the condensate return). For some homeowners, the aesthetic and space-saving benefits of eliminating the large steam radiators may be worth the expense.

Source: EERE, US Department of Energy

Even the most energy-efficient heating and cooling system will fail to save you money if it is installed incorrectly or improperly adjusted.

Here are some further tips on choosing contractors:

• Ask neighbors and friends if they have worked with a contractor they would recommend
• Focus on local companies
• Look for licensed, insured contractors
• Ask about previous experience
• Check references
• Inquire with the Better Business Bureau.

Use these methods to select several contractors, then get at least three detailed, written bids. Each bid should include an agreement to provide written calculations (listing the procedures and standards that will be followed), equipment and installation warranties, a payment schedule, and a firm completion date. Avoid making your decision solely on the basis of price. The quality of the installation should be your highest priority, because quality will determine energy cost, comfort, and durability.

Source: EERE, U.S. Department of Energy

When replacing an existing heating and cooling system, it’s important to first consider the limitations imposed by your current system. Of course, it is possible to install virtually any heating and cooling system in any house, but the cost and aesthetic impacts may be unacceptable for you. When selecting a heating and cooling system for a new house, your options are generally much wider, although your builder or developer may place limitations on your choices.

For both new and existing homes, it’s important to first maximize the energy efficiency of your home. This is the most cost-effective means of keeping your home comfortable, no matter what climate you live in. After doing so, be sure to do what you can to make use of passive solar heating in your home and consider whether ventilation can keep your house cool on warm days, or if you really need artificial cooling. Only after exploring these topics should you decide on the type of system you want and work with a contractor to figure out the optimum size for it.

Source: EERE, U.S. Department of Energy