What is the source of the $20 house-price increase for every $1 in utility bill savings?

Q: Can you link to the DOE study on home value?

You can download it here: https://www.thefreelibrary.com/Evidence+or+rational+market+valuations+for+home+energy+efficiency.-a021276611

It was published in The Appraisal Journal in October 1998 and authored by Rick Nevin and Gregory Watson

Q: for this DOE study of $20 gained for $1 savings – is that $1 per annum or $1 per month? [Ken Calligar] [[email protected]]

It is $20 for every $1 in annual bill savings.