The heating and cooling systems for a home are a key element of occupant comfort every hour of every day. They also have the biggest impact on the environment because they use more energy than any other system in most homes. A thoughtful, well-designed HVAC (heating, ventilation and air conditioning) system will affect significantly the home’s comfort such as whether there are cold or overly warm rooms, system noise, and drafts, to name a few concerns. Operating costs can be reduced as well.
The HVAC design process should begin with a discussion of what the occupants prefer in terms of heating and cooling temperatures for constant comfort. This may vary between individual family members. Typically, an HVAC system is designed to achieve specific “standard” heating or cooling goals at certain outdoor temperatures. If the homeowner wants to vary from the standard, say, to 68 degrees on a 90 degree day, it is important to know so that the deviation can be incorporated in the design from the outset. Some homeowners don’t use air conditioning, which also affects HVAC system choices. Some clients have large art collections or a lot of antiques that require consistent humidity and temperature levels. All are important HVAC design considerations. High performance insulation installed in optimal locations is also a factor.
Ventilation, the “V” in HVAC, which is very important for occupant health in a tight home, may be in the form of a whole house heat recovery or energy recovery ventilation system, which provides constant fresh air but is energy efficient. With this equipment, heat and humidity can be captured from exhaust air and used to treat incoming fresh air.
There are many types of energy efficient heating and cooling systems in today’s marketplace. Homeowners trade off comfort, ease of use, flexibility for different living conditions and occupant preferences, environmental concerns and installation and operating costs when making their choices. If high efficiency boilers or geothermal systems are chosen, there is an opportunity to satisfy domestic hot water needs at a very low cost so the HVAC and domestic hot water systems should be integrated and costs evaluated together.
Other elements to consider when specifying HVAC systems include programmable thermostats, well-sealed ductwork and the integration of solar.