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Hey Folks,

I've got a unique heating/cooling situation in my Northeast raised ranch home. The home was built to be approximately 1500sq ft, two levels, with a garage basement. The previous owners added on a 1000sq ft portion to the house that spans the three levels. Clearly they weren't real concerned with how it stays warm because the only half finished it.

The original portion of my home is an oil burning forced air system and it does very well for that first 1500sq ft. The issue is that it was never designed to heat that other 1000sq ft.

The surprising thing is that they actually ran the duct work for the entire addition and connected it to the main system so the other rooms DO receive heat, but it's generally 3+ degrees cooler in that portion of the home and even up to 10 if you close the doors.

Another surprise; they actually ran radiant in floor heating throughout the entire addition (including the basement room) BUT they never finished hooking it up. There are pumps, expansion tank, a controller, and a great big water heater that was never connected.

So the bones of this project are good, but I'm trying to figure out the best route to go here. I see two options.

1. Finish the radiant floor heating. Quotes have come in at $3000 and $3900 for this.

or

2. Close off the main heating system from the duct work in the addition and add a second much smaller forced air heater to supplement the addition when the main one can't keep up. The contractor's BTU estimations have come in at 20,000 all the way to 40,000 so an electric forced air furnace could be around $600-$800.

Thank you in advance!
 

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What fuel is the water heater that was never connected? Is this a domestic water heater or heating boiler?
What area of the country is this in?
Get a load calculation for the addition to determine size.
I’d not suggest an electric furnace. It can be very expensive to operate.
 

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What fuel is the water heater that was never connected? Is this a domestic water heater or heating boiler?
What area of the country is this in?
Get a load calculation for the addition to determine size.
I’d not suggest an electric furnace. It can be very expensive to operate.
It was a very large electric water heater. I'd imagine it doesn't even work at this point. Domestic heater, non-boiler. All of the plumbing guys tell me to get a tankless boiler rated for floor heating or you'll waste a lot of money on electric costs.

The load calculations have come back from the contractors with needing 21,000 BTU all the way to 51,000 BTU. My impression is that it is on the lower side as the original heating system does most of the work.
 

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Does the addition also have a return duct connected to the furnace. Or is the only return in the older section of the home.

What size is the current oil furnace.
 

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Does the addition also have a return duct connected to the furnace. Or is the only return in the older section of the home.

What size is the current oil furnace.
Yes, it has a return on both levels.

Current oil furnace is a 3/4 HP 4 Speed 119,000 BTU output.

I have also considered adding a booster to try and push more air to the addition, but I'm not sure if that would be effective or not.
 

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In all likelyhood the original trunk lines were not enlarged for the addition and they just tapped off of them.

119k output is a heck of a lot of heat, the entire house probably needs well under 80k - you probably just need the duct system fixed.
 

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In all likelyhood the original trunk lines were not enlarged for the addition and they just tapped off of them.

119k output is a heck of a lot of heat, the entire house probably needs well under 80k - you probably just need the duct system fixed.
Would it be more prudent to fix the ductwork or simply add the radiant?
 

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Don't know - depends on the layout of the house.

Fixing/re-doing air ducts can be very expensive, but so can installing radiant.

Forced air is harder to zone than hot water. If the addition is like a bonus room has much higher heat loss relative to area than the rest of the house, wise for it to have it's own thermostat.
 

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Yes, it has a return on both levels.

Current oil furnace is a 3/4 HP 4 Speed 119,000 BTU output.

I have also considered adding a booster to try and push more air to the addition, but I'm not sure if that would be effective or not.

Will the return hold a tissue to it while the fan/blower is running.
 
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