About the only thing I did myself was run the ducts to and from the water heater. I duct in from the attic so the water heater's heat pump intake takes in warm air to improve the water heater's efficiency when it heat's the water tank (it doesn't have to run as long while it's consuming only 380W of power). And during the warm half of the year when I'm trying to cool the home, I duct the water heater's cold air by-product into my home HVAC's air intake (so that my home variable speed heat pump can stay in low power mode a couple hours longer each day because some of the air it takes in is already cooled by the water heater's heat pump).
If you're better with your hands than me you'd probably save more on labor than I did. Without my math nerd number crunching as a software engineer (most of my work was on the back-end data side), if I had used only normal folks' math I might be getting only 70% free power instead of 80% free power. But if you're more of a hands on worker and don't have the math nerd, your saving on some of the labor might make your initial costs low enough that your payback time period is shorter than mine.
[[ I duct in from the attic so the water heater’s heat pump intake takes in warm air to improve the water heater’s efficiency]]
Excellent idea! We have a “Whole House Exhaust fan” which draws air from outside I. Through the windows, and up into the attic, which ends up cooling off the attic, but that is just wasting the “free heat” which could be used to help heat, or keep hot the water heater water (not so much in winter, but certainly in summer). The fan is great on cooler nights, (but sounds like being on a runway with jets taking off in all directions lol) but when humidity strikes, it isn’t much use even if it is a little cooler than inside ai.r - we usually run a small room ac in the ,iving room only, at the very worst of the Humidity (heat we can take, but the humidity is miserable when temp is over say 85-90 degrees-or so)
We end up having to run a dehumidifier in the cellar because of so much water in the air- can’t afford to run one upstairs plus ac, but the ac does act to draw moisture out of living room which is where we spend the majority of time., but sure would be nice to dehumidify the whole house efficiently- again, the heat we don’t mind so much- if it’s dry, not an issue, but the humidity is murder on us now.
I tried a “swamp cooler” where a fan blows air over ice, which cools the air, but it doesn’t remove moisture unfortunately and doesn’t work all that great.