Complaints about forced hot air usually stem from uncomfortable temperature swings or dryness.
Large temperature swings can happen for several reasons:
1) Oversized heating systems
In the past, it has been common practice to install heating systems that are 2 to 3 times too large. These systems send out a blast of very hot air over a short period of time and then shut off when the thermostat detects that the desired temperature has been reached. A appropriate sized system that runs for a longer period of time provides a more even and comfortable distribution of heat. The photo below is a perfect example. We found this 15 ton boiler in a 6 ton house.
2) Location of the thermostat
Thermostats in rooms heated by the sun may cause the rest of the house to be cold. Alternately, a thermostat that is located in a room that tends to be cooler may cause heat to come on in other rooms that are already warm. Thermostats should be located in spaces where comfort is a priority. An experienced HVAC installer will be able to choose a thermostat location for optimum performance and comfort. Many comfort issues can be resolved by moving the thermostat to a more appropriate location.
Combustion based forced air heating systems are drying because the hot humid exhaust air is vented outside with dry cold air coming in to replace it. Because geothermal systems do not have exhaust or fresh air make-up, this exchange of hot humid air for dry cold air does not happen.
No matter which type of heating system you have, humidity can always be added during the winter months. We have seen the following techniques:
- Stand alone or central humidifier
- Boiling a pot of water on the stove
- Vent a clothes dryer into the room rather than outside
- Run a hot shower with the bathroom door open and the ventilation fan turned off