Will this affect my heating bill?

[Mmfh]

Hey everyone,

I did something my wife is pissed about, I cut a hole in our furnace. Our furnace for the house is in the attached garage, the same garage I work in. The supply plenum is under the furnace and the supply goes into the crawl and up into the rooms through the floor openings.

I cut a 4 x 10 hole in the plenum just below the furnace and put a register in the hole that I can shut off when not in the garage. When this register is all the way open or closed I can't feel a difference in air flow in the house.

My wife thinks our heating bill is going to go way up now that I'm taking some of the heat from the house and putting it into the garage. I don't think so.

What says the Garage Journal? This register helps with the garage heat but its not enough to keep it above 50 in there without any other help if its cold outside.

What am I doing to my heating bill for the house? Was this a stupid idea?

Thanks very much!

Mm

 

[240sxguy]

I am pretty sure that's a code violation if you care. A direct pipeline for carbon monoxide to get from the garage into the house.

It makes sense your heat bill will go up, but it may be marginal enough for nobody to notice.

 

[Mmfh]

I am pretty sure that's a code violation if you care. A direct pipeline for carbon monoxide to get from the garage into the house.

It makes sense your heat bill will go up, but it may be marginal enough for nobody to notice.

I had not thought about CO getting in the house from the garage, I'm on the pressure side of the heat, the supply side before it gets to the house. Should be blowing out into the garage and not sucking in flumes from the garage, right?

 

[Bronson]

The thermostat is in the house. When it gets satisfied,it will shut the furnace down. It will run longer to satisfy the thermostat, theby using more fuel. Also a code violation, probably.

 

[Super Sport]

My dad's house, built in the 60s, had a wall register run into the garage off the furnace. Because less heat is going into the house, it will take longer for it to get up to temp and use more fuel. Same concept as closing off vents in rooms you don't use...it saves money.

 

[chickenhauler]

It will probably be a very small amount, and like mentioned, probably not even noticeable on your bill. The danger of CO isn't when the furnace is running (like you said, there's positive pressure), but when it shuts off there's a direct run from your register in the garage to the floor registers in your house.

My house has a two car garage in the basement, with a few registers, and some pretty leaky return air vents. Never had the detector go off, but any fumes at all do go straight upstairs.

 

[larry_g]

Think about your air flow through the furnace before you cut the hole into the garage. It would pull air from the house, move it across the heat exchanger, and blow it back into the house repeatdly. No effective pressure change within the house and the system neither lost or had to have makeup air. Now that air is being bled into the garage one of two things have to happen. 1. Air from the garage has to be returned to the furnace to be reheated keeping the inside/outside air pressure the same. 2. No air from the garage is returned to the furnace so either no air comes out the new heat vent because there is no cold air return from the garage or the heated air from the furnace into the garage leaks out past the garage doorto the outside. This leaking air creates a negative pressure in the house relative to the outside atmosphere so air starts coming into the house from the outside due to the pressure differential. That air coming into the house will be relatively cold and you will have the heat that air also.

So you either return contaminated air from the garage to the house, or create a pressure differential that requires you to heat outside air rising heating costs a proportional amount to the cold air filtering in.

lg
no neat sig line

 

[Frank The Plumber]

If a door goes to the garage the high pressure air from it will be pulled into the low pressure home more easily. Add this to Larry G's stuff too whom I agree with.

You really would be better off just getting a small cheap furnace for the garage, fuel cost would be more efficient that way and safer over all. Your home is going to smell like your garage all of the time. Any painting etc is going to funk the house up.

 

[Mmfh]

You guys are probably right, it wasn't the best idea. Its just so cheap and easy to get some heat in the garage that way.

I'll start checking around for a cheap way to get some heat from another source. Maybe one of those MrMaxx heaters like the one I helped put into a buddies shop.

You do know I have to find some way to not tell my wife she was any kind of right about this?

Thanks very much!

Mm

 

[larry_g]

Guy at work used to say " If you have to eat crow it's better to eat it fresh."

lg
no neat sig line

 

[NUTTSGT]

You guys are probably right, it wasn't the best idea. Its just so cheap and easy to get some heat in the garage that way.

I'll start checking around for a cheap way to get some heat from another source. Maybe one of those MrMaxx heaters like the one I helped put into a buddies shop.

You do know I have to find some way to not tell my wife she was any kind of right about this?

Thanks very much!

Mm

Just tell it it wasn't keeping the garage warm enough to use. Go out and buy a heater for the garage. Then you have the reason to close the hole back up.

 

[pop pop]

Just tell her you decided you would listen to her and will get a heater for the garage. You'll get bonus points!

 

[wolftrucking]

If you dont spend that much time in the garrage I dont think it will make a difference in your heat bill but CO may be an issue, I realy dont know without looking at it. If you keep it that way at least invest in Co detectors for each floor. If you dont spend days at a time in the garrage, A good set of Carhatt bibbs should do the trick.

 

[555]

We had a two story house in Ohio and the previous owner had made the same modification to "warm" up the basement laundry room. We missed it, the inspector missed it and we went through heating oil like crazy the first two months. It was to the point where we decided we couldn't afford to live there. My wife noticed it first, found the register and closed it. Our heating oil bill usage was reduced over 60%. The furnace was running full blast trying to keep the upstairs thermostat happy.
555

 

[koditten]

How did CO, as in carbon monoxide get into this conversation? Todays' new cars put out so little CO you can't even kill yourself properly.

That being said, you really aren't going to gain much by having that vent going ot the garage. You furnace needs to pull cool air to be heated and pump it out. You only have a vent. Shortly after the fan on the furnace starts the garage will be pressurized. The air to be heated will come from other parts of the house and not much will be going into the garage. Might be enough to keep the paint next to the register from freezing tho.

Unless you are doing lots of tuning on a pre '70's muscle car, CO is not going to be a contaminate. The smell of combustion will be noticed tho. As for code violations, yep, most areas prohibit this.

 

[dirttracker18]

I am suprised you can even put your furnace in the attached garage. In Ontario that alone would violate code as the potential to pull in CO2 (and anything else in your garage) is there.

 

[jumpingryan]

It won't heat the garage.... you have no return to the furnace.

You can't pressurize a space with warm air, with no return. Hot air won't flow through the space.

That being said, what you are doing is dangerous to your and your family, bringing in crappy air from the garage into the house..... CO2, Gas fumes, oil fumes, rotting garbage (if you store yours there) etc etc.

R

 

[Falcon67]

It won't heat the garage.... you have no return to the furnace.

You can't pressurize a space with warm air, with no return. Hot air won't flow through the space.

That being said, what you are doing is dangerous to your and your family, bringing in crappy air from the garage into the house..... CO2, Gas fumes, oil fumes, rotting garbage (if you store yours there) etc etc.

R

Beat me to it. You're ******* in the wind. Close up the hole, buy some nice flowers and maybe dinner, **** it up, while she's all soft that you're manly enough to admit an error in judgement score a budget to get a shop heater.

 

[Kevin54]

If you don't have a return in the garage, then how will CO2 enter the house, unless you have a door cracked to the house. A garage is not real airtight like a house is, so you wouldn't be deadheading the heat into a closed airtight room.

 

[StaggeringGoat]

My furnace is about 16 years old and has been leaking hot air into the garage since it was installed. Where the flexible duct transistions to the metal duct, it must leak as much as a normal register in the house.

I could fix it, but, I like the extra heat in the garage. It still isn't enough to keep it "warm", but my gas bill isn't that much either.

 

[6768rogues]

You are essentially pressurizing the garage and putting the house under negative pressure. The pressure difference will force air from the garage to migrate to the house through any path that is available. Also, since the house is under negative pressure it will be trying to get makeup air from anywhere available. It will pull air from the garage and from any crack in the house, making any potential draft worse.
Our code in NYS prohibits what you did.
Your wife is right, you did a bad thing. Let her win this one.

 

[Displaced Hokie]

Unless you leave the car idling in the garage for hours, there will never be enough CO in there to cause a problem. Not to code, but big whoop. Just seal it up if you are going to sell.

My old house had where someone had done that (they put a vent in there you could open/close). I'd open it when I needed some heat or some dry air in there. Otherwise, I kept it closed.

 

[StaggeringGoat]

Unless you leave the car idling in the garage for hours, there will never be enough CO in there to cause a problem. Not to code, but big whoop. Just seal it up if you are going to sell.

It's not just cars that can make CO, an old/broken furnace can do it to. That's why they're located out of the living space.

Just another point for everyone burning fuel in their house to have multiple CO detectors, there's no excuse not to. It's the law in Oregon now.

 

[Kevin54]

It's not just cars that can make CO, an old/broken furnace can do it to. That's why they're located out of the living space.

Just another point for everyone burning fuel in their house to have multiple CO detectors, there's no excuse not to. It's the law in Oregon now.

S.Goat......maybe in Oregon, the furnaces are outside of the living spaces, hence in a garage, but not all areas of the country are the same. My furnace is in a closet right by the kitchen. My neighbors is in a hallway. Some of the brand new houses have them in a garage, others have them in finished basements.

Personally, I don't see where having a heat duct into a garage is going to be dangerous as long as there is not a cold air return. Sure you may be pressuring the garage, but a garage has leaks around the big doors, at the corners, etc. It is not sealed tight like a house is sealed.

IIRC, there was a discussion on this sometime back. More likely last winter and the consensus then was it was fine as long as no air returns were cut in. I think my biggest concern would be for a mice or two to get into the register.

But on the other hand and just to be safe, pick up a couple of those oil filled radiators from one of the box stores. My wifes 20x20 building stays at 70 degrees with two of them, one on low and one on medium. They are only around $49/ea and do a fantastic job.

 

[Bronson]

Kevin just mentioned the oil filled radiators. I used to have one in My small insulated work shed. I had some of those hanging window sash weights left over from when I remodeled My 1940's windows. I took some safety wire and hung 3 of the sash weights over the oil filled radiator, they hung like wind chimes. The heater would heat those cast iron weights up and, when it was satisfied by the stat, those heavy cast weights kept radiating heat for a long time. I cant prove that it saved any electricity, but it sure seemed to work well. I used the same set up on a mud room off the back of the house. Sveral of My friends copied the idea, and all agreed it worked very well. Thermal mass.