Director for technical affairs Giles Willson said it is impossible to give a single standard price for energy-efficient windows, as all homes are different.
But he noted that since windows last for about 30 to 35 years, people will find they make savings after the initial investment.
He suggested those looking to get cheap gas bills should log on to the BFRC's website to look at the carbon calculator.
According to BFRC data, people in single-glazed houses who install energy-efficient windows could cut their carbon emissions by a fifth.
This could result in a £470 saving on their energy costs in a year.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.