Hydronic Forced Air "Furnace" or "Air Handler"?

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I was always wondering about a DIY version of this until I finally see this type of setup. Has anyone used or install it in person? Supposedly a non floorboard solution and you can use it with a boiler or domestic water heater and set it to lower temp than combustion. What kind of license do you need to install (since you are dealing with non combustion and non refrigerant, a plumber?)

Actually I was thinking, if I can get my hands on these water to air heat exchanger (selling for $120-150 new with potable rating) and mount it to a recirculation pump (the one for faucet water in the morning), then a incubator thermostat to turn on and off the pump and blower fan, you can actually run it at a very comfortable temperature all day using your water heater (say you have a 90+ high efficiency one).
 
In a living space, floor heat is much more comfortable than any sort of forced air. It should only be considered for utility / workshop type spaces.

Combined heating / potable loops are not always legal, or advisable, since the water in the heating section goes stagnant in the summer season.
 
In a living space, floor heat is much more comfortable than any sort of forced air. It should only be considered for utility / workshop type spaces.

Combined heating / potable loops are not always legal, or advisable, since the water in the heating section goes stagnant in the summer season.
Obviously, but I am not going to remodel my home for that. What I am planning to do is to reduce my heat output from my oversized furnace to a much lower and continuous temperature by water heater temperature. Regarding to summer water stagnation, I'm planning to use a smart switch to turn cycle some hot water around every day at, say 7am for 1 minutes. If I have a pump already and it is 110V, adding a smart switch is only $10-20.

My goal is to reuse everything I have with 1) no HVAC contractor time (maybe plumber to hook up a pex tube and a tap between water heater and the water to air heat exchanger), 2) no new equipment other than some easy to source components (circulation pump, incubator thermostat switch, pex and related plumbing, potable water to air heat exchanger). If all the parts end up being $400-500 it would be great, much more comfortable than having 100k BTU blast at you for 1 minutes every 15 minutes. Just keep the blower fan running and set the circulation pump on/off with the incubator thermostat, and slide the heat exchanger in the duct.

And it wouldn't cost like $7-10k for a modular furnace.
 
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whats your primary fuel source... gas or oil?

i would install hydronic oil filled electric baseboard heat if you have the room in your electrical panel 220v units. you can size the units for the rooms size they start as small as 2 foot up to 8 ft install them on individual thermostats. therefore each room can be heated independently and only heat when you want to. i have forced hot air i cut my oil bill in half i haven't noticed any outrageous electrical bills either.
 
It is gas. It is oversized for our house and therefore short cycling and very uncomfortable. I do not plan to remodel so I do not plan to do resistive heating. Not really using heat enough to justify any remodeling for that (about total of 100 therms in the winter per year), main concern is I do not want to spend money but I want a constant low heat to warm the house slowly. Water heater is there already and using the hot water to warm the ducted air would be ideal, if everything is DIY or a plumber can install easily without permit.

Wife still wants carpet in the room, and we move around the house (we only warm the house during evening and turn off furnace at bed time), total of about 1500 sqft space and 1700 sqft volume (cathedral ceiling in living room) and 3 ton of AC is perfect in the summer. I figure based on our cycling our furnace should downsize from 100k BTU to about 30k BTU to be ideal, so a water heater heat exchanger in the duct and reuse the air handler would probably be just right.

So Taco pump, heat exchanger, pex tube, T adapter, incubator thermostat, 110V smart switch, the labor to install them together in the duct, then run it in the winter for 72F on 76F off for the pump and constant on air flow, smart switch to turn on the pump circulation once a day for 1 min at 7am. As long as there is no water leak it would be just right and comfortable.
 
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