Basements are typically concrete perimeter walls and wood rim joist at the top.  They present 2 thermal challenges for the home.

1. Basements being the lowest position in the home makes them vulnerable to stack, or chimney effect.  Air leaving the homes upper floor into the attic pulls in air at the bottom Rim joist of the basement.   The wood boards that hold your floor joist together are called rim joist, these typically have 1 foot square insulation squares in them showing evidence of the stack effect with dirt marks on the backside of the fiberglass insulation.

Fortunately there is an easy fix for this leaky spot.  PEC removes the fiberglass insulation and then spray seals the rim joist area with 2″ of closed cell foam.  The results are minimal cold air, reduced dust, and greatly reduces the possibility of  bugs or mice coming into the living space

2. Because basements are concrete, which has less than an R-2 thermal resistance, basements are typically 10 to 15 degrees colder than the upstairs in winter months. This has a bigger impact on the energy use and comfort in a home than most people realize. The other issue with colder air temperatures in the basement is that the duct work is typically in the basement.  

In order for the homes thermostat to be satisfied on the upper levels, the metal ducting has to be heated up before it can deliver the thermostat setting.  So the answer is insulating the basement perimeters with continuous wall insulation. This can be done with either Fire rated Foam board or white vinyl faced commercial grade fiberglass.