# moving heat runs/cold air returns



## hancam68 (Sep 2, 2008)

My husband and I are currently remodeling our 100+ yr old house, and we have been removing walls to make one large kitchen/dining area. The original heat run and cold air return layout in each of these rooms was odd, to say the least, so we figure we will pull all ductwork from these rooms and layout again correctly. Our furnace is forced air, 140K BTU. Currently there are 2 cold air returns in the diningroom (right in the middle of walkways), and we are trying to calculate how many heatruns/air returns are required by room, as well as proper placement. The total open space in this room is now 25x19. Any help in the right direction would be greatly appreciated.!! :wink:


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## Winchester (Aug 27, 2008)

Reminds me of our old home (memories ). Previous owners did most of the renovations but they left some of the wiring and HVAC a little under par.

I am simply a DIY guy and don't pretend to be a professional but will give you my opinion from what I have seen and delt with. A diagram of your new layout may help others here immensely but here goes.

Normally I see one heatrun in a kitchen. Usually found under the cabinets with no cold air returns. You don't want to recirculate those kitchen smells.

I think an additional 2 more supply lines would be sufficient for the dining area with one larger cold air return.

Supply lines are normally located on the perimter of the room or exterior of the home while cold air returns should not be located in these areas but located in the interior of the room.

I believe many suggest to place cold air returns up high in the wall. This helps more so in the summer months so that the warmer air can be pulled from the ceiling giving you a good flow across the room.

Best of luck!


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## 1610 CUB (Jul 19, 2008)

I would think that for a single R/A duct it should be a 12" round to a hole that ='s 100 sq/in. Or 2- 8" round ducts, 50 sq/in holes. That should make for a nice quite return unless its right next to the furnace!
Is that all the return in the whole house?


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## Winchester (Aug 27, 2008)

1610 CUB said:


> Is that all the return in the whole house?


Good point! Also if there isn't adequate returns upstairs (if you have a 1.5 or 2 story), you might be able to incorporate that into the rennovations as well.
This was an issue with our old house. 1 small return for the whole upstairs. Didn't work well to say the least.


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## hancam68 (Sep 2, 2008)

We don't have any cold air returns upstairs, didn't know it was required, you learn something new everyday. Our ductwork is not set up in the most advantageous manner, I think they were just excited to have indoor heat and put them where ever they could (lol). Some rooms seem to have too many, and some none at all. That's one of the reasons I liked this chatroom, I need a better education on how they work to get the most out of my $$. I prefer sweat equity if I can help it.


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## 1610 CUB (Jul 19, 2008)

Do you have A/C? If you do how many tons is it, Also what is the sq/ft down and the sq/ft up. How many rooms down/up. Then we shall see....... j


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## Winchester (Aug 27, 2008)

1610 CUB said:


> Do you have A/C? If you do how many tons is it, Also what is the sq/ft down and the sq/ft up. How many rooms down/up. Then we shall see....... j


Yes, if you didn't have AC this wouldn't be as much of a problem.

During the summer in our older home, the cold air return problem prompted us to purchase window air conditions to help sleeping conditions. Winter really wasn't a problem.

If you do have AC, hopefully you can at least install one larger return in a common area like a hallway, placing it towards the ceiling. Then just remember to keep doors open to help circulate the AC.

Also during the summer, it isn't a bad idea to turn on the furnace fan to help the circulation and even out the temperature differences.

Do you notice much for temperature difference from floor to floor?


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## hancam68 (Sep 2, 2008)

No A/C, house is just under 3000sq ft. It gets a little warm upstairs in the summer (Upstate NY), but ceiling fans are fine for me. 4 bdrms. One side of the house is balloon frame construction, the other side is post & beam. Creative building in farm country, lol. I think that's why they had to be creative with how they layed out the heatruns (or they were just too lazy). My biggest concern was to make sure we put adequate heat on the main floor since the bedrooms have old style ducts which are large square units (we'll replace that duct work as we do the downstairs). 

The kitchen/diningroom currently has 2 heat runs (one in the middle of the room in the diningroom (which used to be a bathroom, long story), and it also has 2 cold air returns (one in front of the stairs, and one that was next to a wall that I am removing). They are both not far from the furnace. I also have in our livingroom 2 heatruns against an outside wall and one cold air return next to the opening to the diningroom. This room is about 18 x 20. The house is a challenge, and as with all old houses, as soon as you open a wall there is something new to be addressed. 

Whoops, went on too long, back to the subject at hand....I was hoping to remove 1 heatrun from the living room, and leave the cold air return. The kitchen/diningroom we will put one of the heatruns under the cabinet (when we finally install those that have been in my garage for 2 yrs). I just wasn't sure where I should put the other heatrun and if I really needed 2 cold air returns, and also where to move it/them (which I think I got an answer for below). 

Any suggestions are welcome, and I'll try not to ramble on about the house from hell. 

:huh:


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## 1610 CUB (Jul 19, 2008)

1610 CUB said:


> I would think that for a single R/A duct it should be a 12" round to a hole that ='s 100 sq/in. Or 2- 8" round ducts, 50 sq/in holes. That should make for a nice quite return unless its right next to the furnace!
> Is that all the return in the whole house?


This was posted to help you with 1 (one) room. The whole house needs lots more R/A. 
I think maybe you need someone to come to your location and size the matter up. I'm sure you can do the work, but there's nothing like being there! Sorry........ j


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## dac122 (Sep 5, 2008)

The general theory would be to maintain the same air circulation volume you have now, all things being equal. Simple in theory but not so simple to implement. 

In the HVAC industry there is something called a Manual J, or load calculation, that will determine how much heating and cooling you'll need and the amount of CFM you will need. It can be broken down by each room, so you will know what needs to be replaced, and what to replace it with. 

With remodelling changes such as this, possibly adding or removing closets, windows and doors, insulation, etc., you will be changing the heat loss and gain of your home, so your actual cooling or heating load may increase or decrease. There is no way to predict without some kinds of objective measurement.

I recommend someone that can run the Manual J for you and tell you how many runs and sizes. You may also have to ask for a Manual D. It will be money well spent and save you the agony of many trial and errors. 

Someone who knows what they are doing for a Manual J will be measuring living volume, number and types of doors and windows/skylights, insulation values on all surfaces, exterior types, etc. They can do this before you start the job and compare it to the new planned renovation, assuming you have details plans. From there, a Manual D, if needed, will help determine what changes to the duct work will make it all work. You might even remedy some existing problems with your HVAC.


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