Begin looking at furnaces that are 95% efficient or better.
This type of furnace is fully modulating and ramps up to the demand, thus conserving energy. This type of furnace also has the capability of a:
- continuous-running DC blower motor (at a low speed),
- which will continuously filter and destratify the air,producing a healthier indoor environment with an even distribution of temperature throughout the home.
If you wish to conserve additional energy, look into installing a geothermal system.The initial upfront cost will be greater, but there are federal and state tax incentives, utility incentives, and reduced rates.
And depending on the construction of the home, geothermal can reduce your energy consumption for heating and cooling by one-half to two-thirds.
To minimize dust and particulate,look into installing aHoneywell F500 whole-house HEPA filter.
Per the manufacturer, this filter has the capability to capture 99.97% of dust and allergy particulate.
For more information:
Read "Are geothermal heating/cooling systems better in reducing energy costs than solar power?" a Q&A answered by Mick Dalrymple.