Emergency Service Available

Our Blog

High Efficiency Furnace Not Performing? This Could Be Why

While installing a high-efficiency furnace is a great way to save energy and reduce home heating costs, it is only part of the equation. If your home is poorly insulated or has air infiltration problems, the efficiency of the furnace makes little difference in overall utility costs. Before the worst of the cold weather hits the Fairfax area, consider making a few changes that will help your heating system provide peak performance.

Attic Insulation

Because heat rises, the attic is the most important part of your insulation strategy. Ideally, the attic floor should be insulated to at least the R-38 level. Often this is done with layers of fiberglass batts, which provide good insulation value but do not necessarily stop air leaking from the interior of the home. A correctly installed vapor barrier can slow air movement, but in some cases, a better option is to replace the fiberglass with spray foam insulation. Fiberglass can then be used in other areas of the home or applied over the foam insulation.

Radiant Barrier

Seasonal swings in the temperature of an attic can be moderated by installing a radiant barrier on the underside of the roof deck. During the summer, this controls the temperature of the attic by reflecting the heat of the sun back to the outside. During the winter, it reflects any heat that is lost back to the attic.

Wall Insulation

Especially in older homes, insulation in the walls may be insufficient, allowing heat from your high-efficiency furnace to escape to the outside. Have a contractor inspect the condition of the insulation. If necessary, spray foam insulation can be added. Use caulk to seal the areas around windows, doors and other openings, and repair the siding where necessary.

For more ideas on improvements that will help your high efficiency furnace operate better, contact the professionals at HVAC Unlimited Heating & Air Conditioning. We serve Fairfax-area residents.

Get the value-focused & trustworthy service you deserve today!
  • For emergency service, please call our office at 703-493-1200.


We have staff on call 24/7 to provide assistance to our customers. We provide emergency service up to 8pm for all customers and 24/7 for contract customers. For quick, efficient emergency services, please call (703) 493-1200 immediately.