A standard to compare costs would be ideal. Right now in the US, your best bet is to repeatedly mention energy efficiency in the listing and use a realtor who understands how to market it. Provide monthly bills to show actual usage and use the analytics which most energy companies and smart thermostats provide. Being able to show 50% energy usage compared to average homes in your area helps homebuyers understand the benefits.
There’s a standard in the EU called Building Energy Rating (BER) which is disclosed when a house is sold. It’s a scale that runs from A-G, with A rating being the most energy efficient.
Anecdotally it doesnt seem to have a huge impact on the asking price.
There is a strong correlation between BER and the age of the house. In Denmark the majority of houses are in category D. Almost every house built after 2007 is >D and EVERYTHING that is built after 2011 is A or B, with a large majority in A.
My house is from 1935 and the statistics tell me that it is practically impossible for me to get the house above C. I think that it is theoretically possible but the required investment will be so big that it makes more economic sense to tear the house down and build it with modern materials and techniques.
