“Eco-friendly” appears in a third of the listings we see, and in most of them it means a bamboo floor. Buyers increasingly know the difference, and so should sellers. Here is what genuinely changes the running cost — and the value — of a home.

The big three

Insulation and air sealing

Unglamorous and first. Attic insulation to current code and sealed ducts typically cut heating and cooling bills by 15 to 25%. Cost: $3,000 to $8,000.

Heat pump

A modern heat pump heats and cools at two to three times the efficiency of a furnace plus AC. In most of our markets the utility rebates cover a third of it.

Solar with storage

A 7 to 10 kW array pays for itself in seven to nine years and adds roughly 4% to a sale price in our data. Battery storage turns it into a backup generator you never refuel.

Nice, but not the point

Recycled countertops, bamboo floors and low-VOC paint are good choices. They are just not what makes a home cheap to run, and buyers are learning to ask for the utility bills instead of the brochure.

If you are renovating to sell, spend on the big three first. We will help you document it: the listings that sell fastest in this category come with a folder of bills, permits and warranties.