well ya that would work good as water coming out of a Boiler is super hot!

A thought I had was Building a Solar Water heater from hundreds of feet of black plastic pipe in a Box with a glass cover air tight and slowly pumping water through it into a Large reservoir Tank in the shop in one of the walls or ceiling area. then pumping it through a Radiator and fan assembly.

Just the tank alone would radiate heat but running through a Radiator with a small fan would dissipate the heat quickly. https://www.youtube.com/watch?v=EO8SyoGmWFw

There are other Solar heaters too made from Aluminum cans same air tight Box and glass cover that draw cool air in art bottom and exit warm/Hot air out the top. They are said to work well. https://www.youtube.com/watch?v=G-nIGjQEtpA

This one looks really interesting, I may give this one a try
https://www.youtube.com/watch?v=gNldYoeRYF0

This guy gets 200 F out of his el'cheapo
https://www.youtube.com/watch?v=XwUT0ytPfLA

Doright wrote:well ya that would work good as water coming out of a Boiler is super hot!

A thought I had was Building a Solar Water heater from hundreds of feet of black plastic pipe in a Box with a glass cover air tight and slowly pumping water through it into a Large reservoir Tank in the shop in one of the walls or ceiling area. then pumping it through a Radiator and fan assembly.

Just the tank alone would radiate heat but running through a Radiator with a small fan would dissipate the heat quickly. https://www.youtube.com/watch?v=EO8SyoGmWFw

There are other Solar heaters too made from Aluminum cans same air tight Box and glass cover that draw cool air in art bottom and exit warm/Hot air out the top. They are said to work well. https://www.youtube.com/watch?v=G-nIGjQEtpA

This one looks really interesting, I may give this one a try
https://www.youtube.com/watch?v=gNldYoeRYF0

This guy gets 200 F out of his el'cheapo
https://www.youtube.com/watch?v=XwUT0ytPfLA

Winters in Wisconsin don't give us much sun to work with

I get that BUT their is a Guy who uses one of these furnaces in Seatle Wa.!!!!! to heat his office. I didn't see temps coming out of it though but he claims it works.

I want to try this idea myself for my shop for winters, believe it or not it gets very cold here living on the edge of Death Valley desert during the winter.