Even before reviewing the options for controlling your home’s atmosphere, the envelope enclosing your home is a critical factor. If a typical desert breeze (okay, a 40+ mph gust) ruffles your hair while you are watching soap operas in the living room, well, no heating and cooling system in the world will operate efficiently under those conditions. For new construction, insure that the outside structure and interior ductwork are tight and pay attention to the R-factors and thermal mass properties for not only the walls and roof, but also the floor. For existing homes, check door and window seals and if additional spray foam insulation can be added to the roof or ceiling, this is the time to do it.

Today’s options for temperature control include much-improved HVAC (heating, ventilating and air conditioning) units, heat pumps and radiant floor systems. By far, the most common are central air HVAC systems. With the majority of those installed today, the condenser coil and compressor for the cooling unit are located outside, feeding refrigerant to an evaporator coil located in the furnace, thus both the heating and cooling of the house are able to share the central air handling system. Good ratings appear to be a 90-95 percent efficient furnace (Annual Fuel Utilization Efficiency - AFUE) and a 14-20 SEER rating for the refrigerated air unit (Seasonal Energy Efficiency Ratio). When qualifying for tax credits, the lower end of efficiency ratings are acceptable, but points have to be made up elsewhere, such as the envelope of the house. Federal law requires a minimum SEER rating of 13 and a minimum AFUE of 78.

Heat pumps continue to be fine-tuned for effective home temperature control. As a combined heating and cooling option, their efficiency results from the fact that they are juggling heat in one direction or the other, between indoors and outdoors, as opposed to generating heat. Heat pumps work most effectively in mild climates with no extreme temperatures, and may require backup or a hybrid system in areas where temperatures drop into the low 20s. Ductless heat pump units are gaining popularity where the refrigerant is piped to small wall-mounted exchangers located in individual rooms. Ductless units are especially beneficial in remodel projects where there is insufficient room for ductwork installation.

Radiant floor heating provides a very comfortable, consistent and quiet home heat. Energy can be supplied by an indirect fired boiler, a more efficient heat pump or a very efficient ground source heat pump. Solar collectors with a backup system are also an effective option for supplying warm water to a floor system.

Ground source heat pumps utilize the relatively constant 55-degree temperature of the earth to manipulate the floor or circulating air temperature in a home. The system requires an array of water pipes and tanks to be located beneath the surface of the ground, and care must be taken to choose energy efficient pumps. The result can be the most efficient, safe and maintenance-free temperature control system currently available, but all factors have to be aligned with efficient operation to produce the desired outcome.

Wading through available options and factors can become burdensome, so initiate conversations with local suppliers, builders and a green building consultant to get on firmer ground. As a rule, the more efficient systems are more expensive, but state and federal tax incentives help offset the initial cost and monthly utility bills will be less.

So what’s on the horizon for heating and cooling? For air conditioning in the Southwest, check out the Coolerado units that utilize indirect evaporative cooling at five times the efficiency of the best HVAC unit. Go to www.coolerado.com. Some manufacturers, like Trane, have a Telephone Access Module (TAM) that allows the owner to cool down the house while driving home from work. Check: www.trane.com.