Akos- you are a genius lol re hwhp exhaust – GreenBuildingAdvisor

So I have been wondering what to do with the 55f discharge air off my hot water heat pump heater. I had it piped for the longest time in my return duct for one of my mini splits. Great in the summer- you just turn on the air handler fan and “free” 0.5 tons AC. Excellent. In the winter- not so great as this cold return air made my mini split work harder. 

Then I read a random thought here by Akos to dump it behind the refrigerator. You are a genius. Why I didn’t think of it is beyond me. 

I have one of those giant countertop depth Subzeros so I determined where it is and from the basement cut a 8×8 hole in the floor from underneath right under the fridge. Piped with some 8” flex duct the hp water heater exhaust and when the fridge is running there is a 65f or so air coming from underneath it. The heat rejection fins are right there so it worked well. I monitor my refrigerator consumption and exposing it to the cold air also reduces its consumption on average of 1/3. A win there too. 

Now I still want my free ac in the summer so I connected the hwhp exhaust to a Y with two motorized dampers- so I can redirect the cold discharge under the fridge or in the return duct. 

Now I have to do is write my automation for my Home Assistant to send the cold either way depending on indoor temp, outdoor temp, if the fridge is running, etc. easy.

The things we do lol… 

Thank you kind sir for the brilliant idea.