Another heating thread: lowering fuel costs

[cfabe]

Well since there seem to be some knowledgable HVAC people checking in on Barbara's thread, I thought I'd get some input into my situation. I've recently graduated college and am living in my mom's house while saving up (agressively) for my own place. I'm not paying rent but I do pay all the utilities. I just cheked into the gas bills from last winter, and it was around $400-450 a month, or about $2000 for the whole heating season. Yikes! I'd really like to reduce that if possible.

The house has a 20 year old natural gas forced air furnace in good operating condition. It's a 1963 2600sft house, and I'll be alone in it most of the winter. Climate is northern Ohio. I had been toying with the idea of buying a used woodburner, but that's a significant cash outlay (cuts into house savings) and my source of free firewood has dried up thanks to Emerald Ash Borer quarrentine, so that's probably out. I do have a fireplace with a heat exchanger, and probably 1/2-1 cord of wood I'll burn, but I don't expect that to help much. I am an engineer, and have lots of practical mechanical experience so I'm open to technical ideas.

[Ben]

What's the insulation situation? Lots of houses of that era have no insulation in the walls (if wood frame or otherwise have space for it), and less efficient insulation in the attic than is available nowadays.

[Azrael256]

BenW ain't kidding.  You can heat 3,000sq. ft. with a candle if you've got good insulation (ok, not really, but you get the idea.).  

I read about some kind of spray foam insulation that has an insane R-value and can be injected into existing walls.  I don't recall if you'll need a contractor to do it, but it's something to look into.  Traditional fiberglass will be a big help if you can't come up with anything else.  You obviously can't fill the walls with it unless you're into drywall work, but a foot deep fiberglass blanket across the entire attic will make an enormous difference.

Check for leaks everywhere.  Buy a cheap can of spray foam from the hardware store, and seal up anything that might be leaking.  Be really sure to check light switches and electrical outlets.  Most of your wiring will be run through holes drilled into the top of the wall from the attic.  Usually the holes aren't insulated at all.  This is bad.  You'd be amazed what kind of draft you'll get through that 3/4" hole into the attic.  Give it a quick squirt of foam, or maybe seal it with duct tape.  As always, windows and doors leak a great deal.  Good weatherstripping and sealing around the frames will help quite a bit.

[cfabe]

The house has insulation in the attic and exterior walls. I don't know how much in the walls. In the attic I would guess that the bats between the joists are maybe 4" thick. Pink fiberglass in both places. More could be added, but the attic has a floor and is totally full of junk so it'd be a monumentous task to clean it all out before insulating. I don't think blowing in insulation is an option because the house is wired with knob and tube and I've heard that blowing insulation over that can cause wire overheating.

Azrael I will look into sealing where the wires enter the walls from the attic.  How do I check for leaks? Feel for drafts? Hold up a candle?

[K Frame]

I lost a long message to you when my computer crashed.

Others have the jist of it, but...

The BEST returns for your heating dollar are almost always realized through sealing off air infiltration and adding more insulation. New windows, especially if you have old windows, can be a big money saver, too, but it can also be really easy to go overboard with windows.

4" of fiberglass is virtually nothing, R-11 at best. For a roof these days you really should have, at a very minimum, R-30.

How in the hell was your home built with knob and tube in 1963??

That's so far outside of the National Electrical Code for new construction at that time that it's not even funny!



NEVER use a candle to check for air infiltration leaks. That's a good way to burn down a home.

There are devices called smoke pens that you can use. Essentially they create a chemical smoke that allows you to see what is going on.

[cfabe]

How in the hell was your home built with knob and tube in 1963??

That's so far outside of the National Electrical Code for new construction at that time that it's not even funny!

Mike, do you know this for a fact? As far as I know all the homes in this development have knob and tube. The builder who did these is well known in the area as a very high quality builder. It's decently modern for 1963, fully grounded, 100amp service with circuit breakers. I've had a number of other people tell me this is unusual as well. But the house also has copper DWV pipe, so maybe the builder was just nutty.

[K Frame]

OK, most resources I'm finding say that knob and tube finally petered out in the 1950s, which means that hangers-on could have been installing it as late as the early 1960s.

It was my understanding that the NEC banned installation of new K&T wiring systems as of 1955, but I may well be wrong about that.

OK, it looks like I am wrong. This link: www.creia.org/technical/pdf/knob_tube_locked.pdf  says that K&T was still being installed into the 1960s.

Jesus, that just floors me.

[Azrael256]

There are devices called smoke pens that you can use

That's not a bad idea, if you want to spend the money for it.  I would simply assume that all of your electrical outlets are leaking air and just seal them up.  You won't get 100% coverage that way, but it's a big start.  You can do the poor man's method (what I do) of lighting a pipe, and blowing smoke at the windows.  You can buy canned smoke if you're not into tobacco.  It's not as foolproof as a smoke pen, but it will definitely show up when you go to pay the gas bill.  Check out anything that goes up into the attic.  I guarantee it's leaking.  Light fixtures, switches, ceiling fans, it all leaks.

You can make a DIY smoke pen with some plastic sheets and a good fan.  You just build a little plastic room around the door, window, or whatever you think is leaking, turn on the fan to bring the pressure up in the pen (drawing room air into the pen), and hose what you're investigating with canned smoke.  Someone on the outside will be able to see the smoke pour out wherever it's leaking.  It's not a professional-grade idea, but it'll run you about $5 for plastic and tape.

If you go to seal up a recessed light fixture, READ UP ON IT FIRST.  If it's set up into the ceiling, you may catch the joint on fire by dousing it in spray foam.  Find out what the recommended clearance on that is before doing anything.  Anything hanging below the ceiling should be just fine if you seal the hole to the attic.  If it needs clearance, consider building some sort of container larger than the minimum clearance (think plywood) and sealing that up.

[Ben]

You can do the poor man's method (what I do) of lighting a pipe, and blowing smoke at the windows.

Given the price of Hoyo De Montereys, that wouldn't qualify as a "poor man's" method for me, but it's a hell of an excuse to have a cigar!  

[K Frame]

A few more points...

The fireplace.

You can get heat out of a fireplace, but you can also end up sucking more heat out of the house than you get back if you don't do it wisely.

If you're burning your fireplace, open a window near the fireplace to provide for combustion air.

If you get a stove insert, don't install it yourself. There's too much riding on the job.

A coal stove can be an EXCELLENT investment, and relatively inexpensive, but you'll have to go through the expense of having a chimney dedicated to coal installed.

Pellet stoves can be about as expensive as gas or electric.

My suggestion?

Close off rooms you don't use. That includes covering the heating vents and any returns in the room, not just flipping the little grate dampers.

Get a programmable setback thermostat and use it.

Turn your thermostat down and wear sweaters.

Spot heat with a radiant electric heater or a little forced air heater.

[Craig]

if you want smoke and no chance of fire, pick up some dry ice.  use salad tongs and keep what you are not useing in a near by cooler.


just dont seal up a house too much.  fresh air needs to be let in too to keep everyone inside healthy.

[Brad Johnson]

Close off rooms you don't use. That includes covering the heating vents and any returns in the room, not just flipping the little grate dampers.

Get a programmable setback thermostat and use it.

Turn your thermostat down and wear sweaters.

Spot heat with a radiant electric heater or a little forced air heater.

+1

If there is less than 6" of insulation in your attic it would be a good investment to have an additional amount blown in. You want a minimum of 12" of insulation. Roughly 60% of your heat migration is through the ceiling, so the minimal cost of extra blown in insulation will quickly be returned in utility savings. Also, if you have ceiling fans set them on reverse rotation at the slowest speed. This will force the warmer air down from the ceiling without being so breezy that it feels chilly.

It sound silly, but go buy a couple of comfy neck wraps. Some light sweats, footies (or wool socks), and a neck wrap will make you feel several degrees warmer.

Almost forgot - is your heat exchanger forced-air or passive? If it's forced-air, you might have an option. Yes, you will lose a lot of air up the chimney, but a forced-air heat exhanger will extract more heat than you lose so it's a net positive return (if you can get cheap wood).

Brad

[K Frame]

Oh, another suggestion.

If you have a fan setting on your thermostat that allows the fan to run independently of the system, turn it on and LEAVE it on.

You'll use a little electric, but you do a couple of very positive things.

1. You'll keep the air temperatures in the house more even, both from room to room and from floor to ceiling in a room.

2. You'll capture heat out of the heat exchanger that normally just goes up the chimney when the furnace shuts down and the fan shuts off with it.

3. You'll be running the air through the filter continually, helping to take even more particulate matter out, which can help make for a cleaner house.


Also, change your air filters REGULARLY.

During the heating season I change my every 15 to 20 days.  I have two dogs that shed a lot, though.

A clogged filter can cut efficiency DRAMATICALLY.

Also, if you haven't had the furnace checked out by a competent HVAC professional, do it now. An out-of-calibration burner setting can not only waste fuel, it can be deadly.

[280plus]

NOOOOO! NOT ANOTHER HEAT QUESTION!!

I don't know about Ohio but here in CT the gas or electric company has kits for putting plastic over windows, sealing wall outlets, weatherstripping and plenty of info on how to save heat $. Most everyone here in the thread has covered just about everything. It helps to wrap your hot water heater with extra insulation, if it isn't already. That smoke pen idea is a new one on me. Insulate the heck out of your attic. And yes, DO NOT cover over recessed light fixtures. If you run your fan continuously be aware that your filter will clog up much more quickly. Once a month replacement has always been recommended but largely ignored. Mike changing his every 15-20 days is enough to warm my little heart. Programmable T'stats work wonders but according to a study done by Honeywell, setting the heat back any more than 4-5 degrees during unoccupied periods can cost you MORE as opposed to saving you anything. According to them any more than ~5* and it costs you more to bring it back up than you've saved by turning it down. A nice new 90%+ furnace will save you a few fuel $ too but naturally requires some cash outlay. Then theres heat pumps...

[280plus]

Here I go being the alarmist again

If you DO tighten up your house don't forget that the fire in the furnace needs air. If you cut off the air supply to the furnace it is just like putting a glass over a candle. We've all seen that, right? Only with a furnace it will go so far as to pull the air it needs RIGHT DOWN IT'S OWN CHIMNEY!! It will also draw down your fireplace flue. Either of these things can cause carbon monoxide to enter the house. (You have to have a fire going in the fireplace. A bunch of people at a kid's sleepover were killed by the furnace drawing down a working fireplace a few years back here) There are guidelines. I could actually probably find and post them from my code book if anybody is interested.

[K Frame]

"That smoke pen idea is a new one on me."

Are you really in the HVAC industry?

http://www.professionalequipment.com/xq/ASP/ProductID.1309/id.9/subID.109/qx/default.htm

I'm not, and I've been using them for years.

A much greater concern with the furnace (and gas water heater) is that a fire in the fireplace can backdraft furnace gases down the furnace flue because chances are you'll never even notice that. If your fireplace starts backdrafting, chances are good you'll notice that.

One thing I favor for new homes with fossile fuel appliances is a closed utility room with an outside source of combustion air.

This used to be the norm when homes had coal burning boilers or furnaces -- grates set into the wall of the basement allowed the system to draw all the combustion air it needed. The home I grew up in had originally had a coal boiler, and there were two grates, one on either side of the basement.

[cfabe]

I do have a programmable thermostat, we have not been using it because everyone was on different schedules during the day, but this winter with my mom in florida and the siblings at college it'll be just me, so I can set that up to turn back during the daytime and night.

I normally do run the fan constantly when the furnace is in use, to keep temperatures even through the house. Interesting about it catching more heat from the furnace, though.

The furnace has a high capacity or high efficency or some such air filter on it that's about an 8" wide piece of folded paper filter. Previously it has been changed every year or so. Should this be more frequent? I recall that the replacement element is rather expensive, $20+.

The furnace was inspected and cleaned last winter. Replacement with a more efficient unit is probably not an option at this point, though it is about due. The Furnace is about 20yrs and the outside a/c unit is even older, possibly original to the house.

I will investigate adding insulation in the attics and sealing air leaks. I know the house has not had the exterior caulked recently, so that's probably the least it needs. Unfortunately my mom is a pretty bad packrat so both of the attics are totally full of stuff, which will make adding insulation a more daunting task.

Brad, are you referring to the fireplace heat exchanger? It is a forced air unit, has a small fan outside the fireplace that blows into a manifold, and then there are maybe 10 1" pipes that come off of that and circle the firebox, and blow out the top of the door unit. I wish there were a way to measure the efficency of this so I could determine how much heat I actually get from it.

[Brad Johnson]

With a forced-air fireplace heat exchanger you can build a small, and I mean SMALL, fire in the fireplace (like, one log) and get and amazing amount of heat. A small fire will minimze drafting and heat loss up the chimney, and will allow the heat exchanger to get the most heat out of the more-slowly moving air. If you have access to cheap wood, it's a great way to heat. You might also investigate a fireplace insert that is completely enclosed. Some of these have forced air heat exchangers that are darned efficient. Don't recall any prices though, and I bet they aren't cheap.

Also, many woodcutters will sell you culls (the not-so-straight and not-stackable pieces) for a fraction of the price of their regular product. If you do not have access to a place where you can pick up wood yourself, call around and see if there is a woodcutter with a big stack of culls he wants to part with.

Brad

[280plus]

Are you really in the HVAC industry?

No, it's just a hobby that has provided me with about 30 years of "fun" and "enjoyment"...

"That smoke pen idea is a new one on me."
I'm not, and I've been using them for years.

I'm from the old school, we used cigarettes or a piece of smoking paper. We were so much tougher back then that we didn't need any new fangled "smoke pen". We have smoke "candles" but they are for something else. Looks like something an (shudder) engineer would use!

LOL...

As a matter of fact I was taught to confirm the direction of rotation of any shaft with the smoke off a cigarette when I was just a young pup. I quit smoking a while ago in case you're concerned.

yes, flue gases can be pulled down the furnace chimney by an operating fireplace or vice versa. It all depends on which one wins. The furnace or the fireplace. Chances are you WOULD notice if it was drawing down the fireplace. Unless you are sleeping.

cfabe, yes those filters are expected to last a year, actually a good setup, better than most. It might be worth your while to change it every 6 months, depends on the buildup you get..

OH! Siding the house will seal it up and add a layer of insulation all around. Never go for the cheap job though.

[280plus]

I forgot, if your house is really tight, flue gases can also be pulled down the chimney(s) by your dryer, kitchen exhaust, bathroom exhaust or your whole house or attic fan. That last one happens here at my house. I have to remember to open a lot of windows if I'm using the whole house fan.

[cfabe]

280, we do have draft problems when we run the whole house fan upstairs. If we leave the damper open in the summer, we get a smoky smell coming from the fireplace when the fan is run. I assume there is probably also some back drafting from the hot water heater as well under these conditions, but it's never set off the CO detector so it must not be too much of a problem. Of course we don't run that fan during heating season. I've never had any smoke come into the house from the fireplace when it was burning, excpet when we forgot to open the damper.

[280plus]

Yup, it's pulling down the chimney and I can almost guarantee it's pulling down the others. Whole house fans will do that, you just have to open the place up when you run them. Newer appliances water heaters and furnaces, have what is called a "spill switch" located just above the open space between the appliance flue outlet and where the flue starts. It's a little round brown thing with a couple of wires attached. It has a red button. If you have them and you haven't ever had to reset them you're ok. If you don't have them you can do the same kind of smoke check. It's a given the whole house fan will cause i backflow. But you can close up your house, turn on your various exhausts and then see if you pull smoke into the space either in front of the fireplace or at the openings I described above on the appliances. Run the furnace and see if smoke pulls in at the fireplace. Fire up the fireplace and see if you draw smoke at the appliances. Use a smoke pen, smoking paper, or cigarette at your discretion.

[280plus]

More...

The beauty of a 90+ GAS furnace is that it uses plastic pipe for a chimney AND to connect directly to outdoor air. Now you  can shut your house up tight as a drum and air to the furnace becomes a none issue.

It's called "direct venting". The same can be done with oil but you can't use plastic for fluepipe. The reason you can use plastic pipe is that so much heat has been removed from the fire that the exhaust is only about 100*F. They are called "condensing furnaces" because the water in the flue gas actually condenses out and has to be drained off.

Sad part. Given the BTU per $ value of NG vs oil an 86% oil BOILER (we can't achieve 86% with an oil furnace, them crazy Germans are working on it though) will still outperform a 90+ gas appliance. NG is actually much more expensive per BTU than oil. And then theres PROPANE! DO NOT listen to Hank Hill! Propane is the LEAST efficient / MOST EXPENSIVE of ALL the fossil fuels.

Let's do the math.

Here's what you do. Find out how much a "Therm" of natural gas costs in your area. A Therm = 100,000 BTUs. Compare that to the price of a gallon of oil. A gallon of oil = 140,000 BTUs.

When we talk about the "Efficiency" of a furnace or boiler we are talking about how much of those BTUs make it into the house vs how many go up the chimney. So a 90% furnace using natural gas will give 90,000 BTUs of heat per therm to the house, the other 10,000 go up the chimney.

An 86% oil boiler will send 120,400 BTUs to the house and 19,600 up the chimney. Generally a gallon of oil and a therm of NG have always cost about the same. I don't know if that still holds true actually.

If anyone wants to post the figures for their area, I'd be interested in seeing them.

[K Frame]

My brother and sister in law were talking about replacing their oil boiler with propane. I managed to talk them out of it using the same sort of financial analysis. They're sticking with oil. No natural gas where they are.

The biggest problem with the 90%+ efficiency gas systems is that the condensate is quite acidic. Many communities won't allow it to be pumped directly into the sewer or waste water systems because of that. It has to be neutralized first, either through chemicals or dilution.

[280plus]

Here's a funny one, given the recent talks we had about GTHP. I just heard of a guy who is putting 2 gas fired inline duct heaters into his existing GTHP system because it will not keep up below 40* ODT. Apparently nobody can figure out why but I'd venture he doesnt have enough heat sink or somehow some of his heat sink is blocked and he's not getting full capacity out of it. I'ts not unheard of for a rock rto find it's way into the system during the assembly process. I was asked to take a look and put my $0.02 in but I declined. I got enough open cans of worms already.