HVAC

Heating and Cooling systems: Much of your home’s energy dollars go to heating and cooling. That’s why maximizing HVAC efficiency is so important.
One way to increase an existing system’s performance is through periodic maintenance including cleaning and tuning.

• Gas –Fired systems should be checked and serviced every two years. If your unit is more than 10 years old it may be time to replace the system with a high-efficiency and correctly sized system. The efficiency of a gas heating system is a measure of how effectively it converts fuel into useful heat. There are two types of efficiency. “Overall system efficiency” gives you the entire system’s efficiency while it is operating, taking in to consideration energy loss through the distribution system. The “annual fuel utilization efficiency (AFUE)” measures the efficiency of the furnace, accounting for start-up and cool down, as well as other operating losses that occur in real operating conditions. New gas-fired heating systems should have an AFUE rating of at least 90%. If you are considering a new system, ask for an ENERGY STAR qualified system to ensure optimum efficiency.
• Electirc systems -
  • Ductless, Mini-Split Heat Pumps

    Ductless, mini-split-system heat pumps (mini splits) make good retrofit add-ons to houses with “non-ducted” heating systems, such as hydronic (hot water heat), radiant panels, and space heaters (wood, kerosene, propane). They can also be a good choice for room additions, where extending or installing distribution ductwork is not feasible.

    

    Mini split heat pump outside unit

    Like standard air-source heat pumps, mini splits have two main components: an outdoor compressor/condenser, and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units.
  • Heat Pump Systems

    For climates with moderate heating and cooling needs, heat pumps offer an energy-efficient alternative to furnaces and air conditioners. Like your refrigerator, heat pumps use electricity to move heat from a cool space into a warm, making the cool space cooler and the warm space warmer. During the heating season, heat pumps move heat from the cool outdoors into your warm house; during the cooling season, heat pumps move heat from your cool house into the warm outdoors. Because they move heat rather than generate heat, heat pumps can provide up to 4 times the amount of energy they consume.

    The most common type of heat pump is the air-source heat pump, which transfers heat between your house and the outside air. If you heat with electricity, a heat pump can trim the amount of electricity you use for heating by as much as 30%–40%. High-efficiency heat pumps also dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer months. However, the efficiency of most air-source heat pumps as a heat source drops dramatically at low temperatures, generally making them unsuitable for cold climates, although there are systems that can overcome that problem.

    For homes without ducts, air-source heat pumps are also available in a ductless version called a mini-split heat pump. In addition, a special type of air-source heat pump called a “reverse cycle chiller” generates hot and cold water rather than air, allowing it to be used with radiant floor heating systems in heating mode.

    Higher efficiencies are achieved with geothermal (ground-source or water-source) heat pumps, which transfer heat between your house and the ground or a nearby water source. Although they cost more to install, geothermal heat pumps have low operating costs because they take advantage of relatively constant ground or water temperatures. However, the installation depends on the size of your lot, the subsoil and landscape. Ground-source or water-source heat pumps can be used in more extreme climatic conditions than air-source heat pumps, and customer satisfaction with the systems is very high.

    A new type of heat pump for residential systems is the absorption heat pump, also called a gas-fired heat pump. Absorption heat pumps use heat as their energy source, and can be driven with a wide variety of heat sources.

  • Electric Resistance Heating

    Electric resistance heating converts nearly 100% of the energy in the electricity to heat. However, most electricity is produced from oil, gas, or coal generators that convert only about 30% of the fuel’s energy into electricity. Because of electricity generation and transmission losses, electric heat is often more expensive than heat produced in the home or business using combustion appliances, such as natural gas, propane, and oil furnaces.

    If electricity is the only choice, heat pumps are preferable in most climates, as they easily cut electricity use by 50% when compared with electric resistance heating. The exception is in dry climates with either hot or mixed (hot and cold) temperatures (these climates are found in the non-coastal part of California; the southern tip of Nevada; the southwest corner of Utah; southern and western Arizona; southern and eastern New Mexico; the southeast corner of Colorado; and western Texas). For these dry climates, there are so few heating days that the high cost of heating is not economically significant.

    Electric resistance heating may also make sense for a home addition if it is not practical to extend the existing heating system to supply heat to the new addition.