Do I have enough air ducts in my house?

The house was built in the early 1950's and there is about 6 inches of loose white cotton looking insulation in the attic, does anyone know the efficiency of this old insulation? should I just add new insulation on top of it?

Cotton Fiber insulation has an R value of 3.85 per inch thickness.

It was common to provide minimal insulation in walls in the 50's. If it is a brick house, it could have face or common brick, 6 inch thick concrete block, and then furred out plaster board. The R value of the wall between 3 and 4. Single pane windows with storm windows are leaky and have an R value around 1.4. Standard double pane windows around 1.9.

Commonly houses have supply ducts and one or two central common returns. If the doors are not louvered, make sure they have enough undercut to allow return air flow, especially if thick carpet has been added. When undercutting a door, score your line with a razor knife to prevent splintering the edge of the cut with your circular saw (you only have to do the top side as a circular saw should not splinter the bottom).

When I was young, our 2 story with basement family home, built in 1950, had a gravity feed furnace -- no blower. Good return air paths were a must.

Without looking at the layout and position of all the ducts and flow rates in detail its hard to know exactly what is going wrong. I do however suspect that you are having problems due to poor mixing of the air in the rooms. An easy and cheap solution to this problem is to add a ceiling fan. Make sure you get ones that are reversible so you can have them blowing upwards when you are heating and downwards when cooling. The ones I have used in the past cost about $50 in Australia so you can probably get them for less in the US.

As for the insulation I don't know what it is, it could and I am not saying it is, be asbestos or contain asbestos. I suggest you go to whoever oversees building works in your area and ask them about it. If it dose contain asbestos you have big problems, DO NOT TRY AND MOVE OR DISTURB IT YOURSELF, you will need to get professionals in to remove it and make sure it's all gone.

Air flow is extremly important, if you do not have a return air duct in each room make sure the doors are kept open to insure air flow. Check to see if your system is balanced, This is best done by a professional tech. However you can check your ducts in the basement. they shoud have dampers (the dampers will have a sheet metal handle on the outside of the duct, it's position will show the position of the damper blade inside the duct) to adjust the air flow to a particular zone. Your furnace blower is rated for a certain amount of CFM, so you can try to balance the system yourself by slightly closing the dampers closest to the furnace to provide more flow to the more remote zones. It'll be a hit and miss process but it's worth a try. Also depending on the age of your furnace you may have a belt drive blower. Check to make sure the belts are tight and in good condition. If your furnace is newer, it may have a multispeed moter. Check the speed by seeing which color wire is connected to the circiut board. Another thought, have you ever had your ducts cleaned? Might be worth considering.

IN ANY SIZE HOME RETURN AIR IS VERY IMPORTANT. IF THE PRESSURE CAN NOT BE RELIEVED IN THE SPACE THE AIR JUST SITS AND CANT BE REHEATED TO WARM THE SPACE. AS THE OTHER GUYS SUGGESTED CUT OFF YOUR DOORS TO ALLOW AIR FLOW BACK TO YOUR FURNACE, CLEAN YOUR DUCTS, INCLUDING THE RETURN AIR, CHECK THE DAMPERING ON THE DUCT WORK. MAKE SURE YOUR NOT SENDING TO MUCH TO OTHER AREAS OF THE HOUSE. BUILT IN THE 1950'S I WOULD THINK THAT YOUR DUCT WORK IS 5 OR 6 INCH WHICH SHOUD BE BIG ENOUGH. THE VOLUME OF AIR YOU ARE SENDING TO EACH AREA IS WHATS IMPORTANT AND YOU CANT SEND IT IF IT HAS NO WAY TO GET BACK.

SORRY I DIDNT ANSWER YOUR QUESTION YES YOU DO HAVE ENOUGH DUCTS FOR THE SIZE ROOMS YOU HAVE. TRY SOME OF THE THINGS DISCUSSED AND IT SHOULD HELP. IT SHOULD ALSO CUT DOWN ON YOUR HEATING BILLS BECAUSE YOU WONT BE TURNING UP THE THERMOSTAT TO BE COMFORTABLE.

One thing not yet mentioned re the uneven heating of the bedrooms is the location of the duct outlets/"registers" viz a viz the/any windows.Ideally the registers should be located under the windows to mix however much cold air is "draining" off them with incoming warm air. Its is acknowledged that to relocate can be a significant project but the benefits can be great and of course, lasting.

The writer also has a house built in this time period and required one register to be relocated in the dinette...it was totally at the opposite end of the room from a large window hence the dinette was basically unusable in the winter. The relocation made "all the difference".

For any readers who might be unfortunate enough to have a crawl-space type house, huge benefits are to be gained from insulating both the supply and return ducts. Let alone the energy savings, the temps tend to be more even room to room, particularly if the duct lengths very greatly. Hope this helps. Gene/guest/ nr Cincinnati, Oh

1st - "yes"...but:

The quantity of 'air ducts' is seldom the correct question, as you will likely learn quickly from replies to your post.

Without getting too confusing or detailed, there are several rather simple, but related, issues you need to look at (all of them) to fully solve your issues. Addressing these and any construction issues will likely not only help to solve your temperature and comfort, but save you some energy.

My own summary:

First, the "one side gets colder" issue is likely related to the fact that any building loses energy (warmth) at the perimeter or exposure surfaces. This includes the floor, if the basement is unheated, and the ceiling, if the insulation is old/settled/uneven/insufficient. The outer walls and windows are the primary culprits.

Is the single supply diffuser under the window (floor type) or near the window (ceiling type)? If not, move it and extend the ductwork.

Is the supply ductwork insulated? If not, insulate it...all of it.

Is there a sufficient return path to get the supply air back out of the room? If the door is not louvered, no ducted return, and no transfer grille present, then the door must be "undercut" to leave about 80% of the square-inches of open path for air as the supply air to the space. e.g. if it's a 6" supply duct, a 30" door should be cut to leave at least 1/2" opening along bottom of door. This can be eliminated as a contributing factor by leaving the doors cracked for a few nights to see if any noticable effect is measured.
*In an older house, 'leaky' construction may be resulting in some of the supply air finding it's way 'outside' through windows or other cracks and leaving your furnace with the unhappy job of sucking in some cold outside air from other cracks, resulting in slightly less-warm supply air temperatures than the original design wanted...

Wall: I'd suggest removing an outlet in the outer wall and checking your wall insulation. You can pry out a back-box and not lose much $ - if necessary - since even if you mess up the box, an insertable replacement box costs little. If your walls are thinly insulated (or have none) there's your first issue. Fix this throughout the house if needed, though this is the most expensive and involved problem & solution. It may include your choice of either outside rigid insulation board and wrap and replacing the siding (if house is not bricked) or insulating inside and replacing the outer-wall gypsum board...and remodeling the house on the inside (which wives generally enjoy and can be used to add receptacles, phone & TV jacks, etc. while you're at it).

Ceiling: Look in the attic. If you have less than 12" of ANY type of insulation, then ADD. Now, before winter. Easiest is to rent a blower for a half-day and have a helper dump packages into the machine while you (w/face protection) distribute the new fluff evenly throughout. This will pay for itself by next winter.

Consider replacing any central lighting fixture with a low-profile ceiling fan. Ensure that the back-box in the ceiling is reinforced type rated for fan anchoring, or replace them. Small blade fan is sufficient for these small rooms, and lowest-speed is sufficient for airflow - you'll want to invest the extra few dollars to get a QUIET motor (bigger-better windings and appropriate electronics = less noise).

Consider having a controller installed by contractor like the fanhandler.com unit, so you have low-but-constant flow at night to even out the temperature throughout the home. A cheap alternative manual solution is to wire a simple standard switch from the same power circuit to the low-speed motor tap, so when the thermostat says 'temp OK, turn off system' you can have the fan run continuously in low speed anyway at night. A friend of mine did this but ran circuit to a simple timeclock unit mounted into the wall on a new 2x4 box, and every night through winter it runs and he says it works great and helped a lot. About the same energy as a single ceiling fan, but circulates air throughout the entire house, and your air filter works continuously.

If windows are older single-pane ones, replace ALL like this in the house with insulated-frame multi-pane windows. That alone will save you enough over the years to pay for themselves.

Oh, and in case it hasn't been mentioned sufficiently, make sure the equipment and ducts themselves are fully cleaned, lubricated, and working correctly (ducts, belts, motors, furnace, new or electronic filters).

I'm sure I didn't quite get everything, but I hope this all helps. Sometimes, like when you're ready to sell the house and don't want to invest in doing it "right," the cheapest solution is to simply run a new electrical circuit above the basement ceiling to the outer walls and install a cheap electric baseboard radiant heater on the outside wall of each bedroom. <cringe>

Boy Sandman..you covered most of it! I might add these tricks. All of yours are wonderful!

Before changing windows, or installing new ductwork, do the simple things to allow your furnace to not work as hard.

pry off the mouldings around windows, fill the gaps with spray foam. Same with doors. Saw off the bottom inch of your doors, or leave them open more.

Find the electrical boxes for the overhead lights in the attic. Bag or box them in...I use margarine containers, and foam it all in so that no air can leak out into the attic. (Don't do this with pot lights....ideally you should do this with ALL electrical boxes, but most wall mounted ones are had to get to easily) Get rid of pot lights that feed into the attic.

Pry up the shoe moulding around the base of the wall (and if necessary, the baseboard. Its cheap.) and run a bead of foam insulation all around the bottom. You could use rubberized caulking...it can handle summer-winter movement better. You want to stick the vapor barrier to the floor if possible.

take off the electrical covers, and install those thin foam pads which will keep air from infiltrating into your living space.

caulk the windows with removable caulking. I jam a string into the gap and hold it there with removeable caulking to make it easier to yank out in the spring.

To decide if you need fancy new "VERY" expensive low E windows try the temporary fix of shrinkable plastic for a season. If you save a lot of energy, or if your draft problem suddenly vanishes...you might think about new windows. After all, the ones you have are already 50 years old. OTOH, the payback time for new windows is very long. Me...I just hang grandma's quilts over my hundred year old windows. Shows them off, they look pretty, and they work just as good. Some peel and stick velcro in the corners helped.

The insualtion in your attick MIGHT have asbestos in it. If so, then you should get rid of it. Otherwise, lay in batts of insulation across the exposed joints in the attic. Be wary of blown in insulation...you could clog the vents over there, under the eaves, which feed into the soffits. If you don't ventilate your attic really well, , you get REAL problems. Every single one of my soffit vents were covered by a misguided former owner who blew in yards of rock wool. Once I got the attic vented, I stopped needing air conditioning in the summer.

Your bathroom exhaust fan is not venting into your attic right? Right?

Some of your duct work may be accessible. Tape up as much as you can reach with silver tape. (don't use duct tape...the only think duct tape is not useful for is duct work. The hardware store guy can sell you the right stuff.) Caulk around the plenum...at the top of the furnace. A bucks worth of tape and caulking will save you hundreds down the line, and more importantly, help keep the pressure up in your duct lines. Insulating it? Well...maybe. If you can get to it easily. Taping is more important.

Where does air get into your house? When you get the bathroom fan going, the kitchen exhaust fan going, the furnace running...you might have a negative pressure in your house. This could be dangerous. Get a qualified HVAC guy to check it out, particularly if you all headaches in the evening when the furnace has been running for awhile.

And have your ducts cleaned at least once a decade by a company who does duct cleaning.

If none of these simple fixes do anything, you can get a duct-fan booster section which will move more air. But it is another energy consumer, but it might be a better answer than yanking out drywall in order to change a 5 inch duct for a 6 inch duct.