New York Renovator

We had our first big freeze last night. The house is pretty cold this morning, but I am stubbornly being a miserly scrooge frugal by refusing to turn on the furnace yet. Truth is, I’m late this year in getting ready for winter! My furnace needs a tune up and new filters yet, and I need to inspect the ducts to make sure everything is working properly.

One of the nicest things you can do for your furnace is changing the filter regularly. But how often does one change the filters? I’ve done a little research, and the answer is: it depends. Haha! Seriously, it does depend on your furnace, your house, and your lifestyle. If you have a lot of pets and a huge drafty dusty home like I do, you should change your furnace filters every month. If you use your furnace irregularly, have no pets, and have a smaller home, every other month or every three months are fine. Most furnaces come with recommendations in the manual; always check that first.

The main purpose of the furnace filter is to protect your furnace’s delicate moving parts from dust and dirt. And some filters come with extra benefits, such as capturing very small particles of dander, dust, and allergens. I only use those now. You should see how quickly they fill up with gunk!

I read a review at Consumer Reports a while ago, and they did a test on furnace filters. The “cheapo” brands (the ones I always got) were horribly non-effective in filtering dust and allergens from the furnace system. The filter that got the highest grades were those by the manufacturer 3M. Those are the only ones I purchase now; they’re called Filtrete Micro Allergen Reduction Furnace Filter. They are, obviously, more expensive than the cheapo ones, but at least they do the job! And we change them every month (well, try to). So I am always looking for deals. I used to get them from my local Big Box stores, but have recently found the filters I use at Buy.com. They come in a pack of 6 and the shipping is very inexpensive. Sometimes you can snag some when there’s a good sale; however, at this time of year, sometimes things are out of stock. Don’t ever wait to order seasonal stuff like this!

It’s important to change your filters regularly. Leaving filthy filters in your furnace can cause the furnace to overheat and shut down; installing insufficient filters can cause dust and dirt to pass into your furnace motor, clogging up the works and reducing the efficiency of the furnace (which means more expensive heating bills). Be sure to change your filters regularly! And if you’re looking for some good prices and great service, check out Buy.com’s inventory.

This blog gets a lot of hits from people searching Google, questioning whether they should cover their cold air return vents.

I just wanted to let you know that it is very unadvisable that you cover these vents. I did for a few years until my Furnace Guy informed me of the details.

Your home needs cold air return vents. The hot air coming from your furnace entering your house must have a source. Unless you have a very sophisticated direct-vent furnace with supply air coming from the outdoors, you need return vents. This keeps the air in your house moving and reduces air pressure from the heater vent air filling your room.

Think of it as a fan in the summer. If you put your fan in your window and open the door, what do you have? Circulating air. What happens if you close all other windows and doors in that room and still run the fan? The fan blades still work, but the circulating air supply is almost entirely choked off, and the cool air no longer vents. It eliminates the fan’s efficiency. Moreover, it makes the fan run and you are still charged for the electricity to run the fan. You are essentially paying for nothing, plus wearing out the fan motor even faster.

A forced-air furnace needs intake air to supply the outtake air. To close off your cold air return vents chokes off the intake air supply. So it not only is costing you more money to do less, it is also making your furnace work harder to run.

My Furnace Guy said that, in a perfect world, every room that has a heater vent should have a cold air return vent. There is a mathematical calculation they use to determine how many return and supply vents a room and house needs. In my old home, I only have TWO small return vents. This is not good. I am trying to fix this, knowing that it is costing me more and making my new furnace wear out sooner. The worst thing I could do is cover my cold air return vents.

So… if you are wondering whether or not you can cover the cold air return vents– no, you can’t.

AT LAST! I have my furnace ducting finished. It has been a long job– took weeks– but it is complete. It took so long to complete this because the ducts are so integrated with the room (walls and floor). I now have three heat vents and one cold air return. I should actually have another cold air return, but I am going to wait on it until I remodel the accompanying room (when we finally remove the crumbling chimney).

I can’t even begin to explain how I did this job, it was so time-consuming and complicated. Cutting the metal with tin snips was the hardest part, I think. Also difficult was screwing in the sheet metal screws.

I do not consider my ductwork to be final. This is something I would truly like a professional to do. Working with metal, and that room by room, is enormously laborious. I had to do this room myself because the cost isn’t in the budget right now. I think I did a good enough job to last us a few years. By then I’ll probably hire my furnace guy to redo everything. Ductwork is pretty intense work. I have great respect for my furnace repairman.

I did not recycle as much of the old ducting as I wanted. This is mainly because the old ducting is 7-inch diameter. Modern measurements are 6- or 8-inch. I was in a real pickle, trying to make things match. I used a few adapters (6- to 7-inch) and I stuck with the flexible ducting. I suppose I could have bought all new 6-inch ductwork, but it would have cost a small fortune for this room.

Anyway, I think my adaptations are acceptable. I can rest easy that we are ready for winter now. The ducting is sealed good and tight. It is free from drafts and finally free from all those spiders making their nests in the holes.

Back when we were thinking of gutting the entire house (we’ve since opted for one room at a time), I got a quote for redoing the entire furnace ducting system: $8,000. JUST for ducts (the furnace is brand new). Yow. I love my furnace repairman, and feed his family well, but I just cannot cough up 8,000 clams for sheet metal.

Now that we are doing one room at a time, I am doing everything in one room at a time– walls, ceilings, electric, insulation, floors, ducts. It is not as efficient as doing all rooms all at once, but this method is more manageable for us (financially as well as for sanity).

So I right now, on top of learning everything else, I am learning how to repair and install furnace ducting. It is actually not terribly difficult, merely distasteful and dirty. The old ducting dates back to the 60s and some dates earlier. It is very, very dusty and rickety. Some pieces I am replacing but I am reusing most of the ducts. I spent a whole day removing everything that connects to the living room (two heater vents and one cold return vent) and scrubbed them clean. The cold air return vent was only sheet metal nailed onto floor joists in the basement, and a hole hacked into the living room floor as a “register.”

You can see the stone foundation and three floor joists through the “register” in the above photo. Unfortunately, the natural gas supply line was installed through the foundation and directly under this cold air return vent– not a very wise decision, because should the gas pipe ever leak, the fumes are dispersed throughout the house and also flow into the living room above.

When I peeled the sheet metal to reveal the joists, great gobs of greasy dirt and dust spilled out. Yuk. Thank God I was wearing a bandana to cover my long hair.

If you look closely at the picture below, you can see what I mean. This photo was taken before I removed 70 square feet of sheet metal nailed to the joists. I had removed the cold air supply duct (where the circle was) to reveal about a 1/4-inch layer of dust and cobwebs coating the joist above it. I am so glad to be rid of this filthy cob job.

There is a system to furnace ducting. You can’t just throw ducts anywhere. Cold air vents (return air) must be positioned in interior walls, and heat ducts and registers (supply air) must be installed along exterior walls. The system of forced airflow works with the natural physics of rising and falling air. Anything else is inefficient (and against some local housing codes). As expected, the ducting system in my house is all the wrong way.

There should be a cold air return vent in every room that has a heat supply vent. Only two rooms in my entire house have cold air return vents (the living room and dining room), and they are both along the exterior wall. Thus my furnace works very hard, and the air pressure in my house is uncomfortable (think of how a cup sticks to your face when you suck in the air from the cup– it creates pressure on your face because of the vacuum you created). Also, my upstairs rooms are absolutely frigid in the winter. One bedroom (15 x 17) has a teeny-tiny heater vent on an interior wall, and that’s it. The heat leaking out of that tiny heater vent cannot compete with the two 3′ x 5′ windows and the 250 square feet of uninsulated walls and floor of that room. All winter, a thick coating of ice covers both windows, and over the years the water has rotted the window panes. I won’t even go into describing the other bedrooms. We freeze every winter up there.

So, the fundamentals are important here: supply on outside walls, return on inside walls. Have enough heat registers for your room (there is a formula for calculating the necessary cfms to square footage). And have an equal amount of cold return vents for your heat supply vents.

So I am in the process of installing another supply of heat in the living room, replacing the dirty cold air sheet-metal cob job with a closed-duct system, and patching/sawing holes in the floor above to accomodate the changes.

This autumn, I have to add more cold air return ducting to the downstairs to make the system a little more efficient. Next year, when we remove the chimney, the new opening will allow me to completely reconfigure the supply/return ducting system for the second floor. The noggin on the first floor make ducting and electrical nigh impossible for exterior walls. I have to work around that!

For now, I am thrilled to be doing even one room as it ought to be done.