I’d like to better control my natural gas usage in our house. The natural gas serves a stove (brand new GE Profile), 5 year old Bryant Plus 80 furnace and a 15+ year old 40 gallon water heater.
I imagine the water heater is not insulated, and since it is located in the basement, installing an insulating blanket would help, any idea of just how much of an energy saving would I get and would it be really that noticeable on my utility bill. Also, what if I replaced with a new water heater? Would I notice a significant decrease in natural gas usage?
Thanks
Tark
Replies
I would guess your single biggest consumer of gas is your furnace. I suspect you will need to do something to reduce the amount of time it is running, either seal/insulate the house better or turn down the thermostat/use a setback thermostat.
I did find my grandma's furnace that hadn't been used in years was leaking gas internally most of which wafted up the flue so it went undetected. Also if you have leaky ducts or poorly balanced ductwork you may be wasting some fuel there as well.
I have no professional expertise, this is just what I have gathered on my own.
You could also see if PGE would do an energy audit.
Karl
A 15YO water heater shouldn't be that bad -- efficiency standards have been in place for the past 25 years or so.
But installing an insulation blanket is cheap and easy, so you might as well give it a try.
Remember that things like hot water recirculation waste a lot of heat. If you have a recirculating hot water setup you might want to put a timer on it or otherwise reduce the heat loss there.
Thanks. I'll try the blanket.
Tark,
1. The most important step you can take is to get an energy audit that includes a blower-door test and infrared thermography of your building envelope.
2. Most homeowners discover that the most cost-effective energy retrofit measure is air sealing work. This involves sealing air leaks, usually at the basement rim joist area and the attic.
3. In many cases, adding more insulation to basement walls or the attic is cost-effective. But your energy audit will reveal the measures that make the most sense for your house.
Martin Holladay, senior editor
GreenBuildingAdvisor.com
Thanks to everyone that has replied. I plan on calling PG&E for an audit, but wanted to take care of the more obvious air leaks first. All the doors have good weather stripping, but as in another post, I'm looking at a product that will seal off the fireplace flue when its not in use.As for the water heater, it is located in an unconditioned and vented basement. The house only has some insulation, mostly in the attic, but Another question. The garage door has these vents openings in them, which I was thinking of sealing. Would that be a good idea. There are not any gas appliances in the garage. Yet the garage is under one of the bedrooms, next to the family and laundry rooms and it does get really chilly.Regards,Tark
As I think someone else said, one of the first things is to check any ductwork in unconditioned spaces (attic, unconditioned basement/crawl, garage, etc). All such ductwork should be tightly sealed at the joints, either with mastic or with the foil type of duct tape. And, ideally, such ductwork should be insulated.After that, look for obvious air leaks out of the "conditioned envelope". A very common source of such leaks is plumbing and flue penetrations into the attic, but also look in areas where there is a soffit (eg, above kitchen cabinets) or dropped ceiling below. Often these areas are not properly sealed, with the stud cavity open to the unconditioned attic.Beyond that you look for the "usual suspects" -- doors, windows, the sill area of basement rooms, etc.
This country will not be a permanently good place for any of us to live in unless we make it a reasonably good place for all of us to live in. --Theodore Roosevelt
Don't seal up the vents on
Don't seal up the vents on the garage door.
They are there to allow the vehicle exhaust to get out, instead of seeping into the house.
Check to see if the walls between the garage and living spaces are actually insulated. The codes didn't used to require that they be insulated, in some jurisdictions.
My folks bought a new house in the mid 70's, that didn't have any insulation in either the garage walls, or the walls between the garage and the adjacent living room. There was also no insulation in the wall of the second floor bedrooms, and adjacent attic spaces for the first floor roofs, over the porch and garage. My brother and I were 18 and 16 at the time and got stuck with climbing in those attics, in the July heat in Vegas, to put in the insulation. It had to be 160+ degrees in those spaces. You could put your hand near the wall of the adjacent bedroom, and feel the heat radiating into the house.
Wrapping your water heater if it already has some insulation may not make much of a dent in your bill. Stanby losss isn't usually large. Your basement isn't heated, but I assume it is tempered (i.e. not outside temp).
If you do a blower door test, also do a duct blast. Leaky ductwork can contribute substantially to forced air leakage due to the pressure differentials the furnace fan can cause.
See if PG&E can do an audit. But remember ... you may get what you pay for. A 'free' audit may not get you much ... although if PG&E offers them, they really aren't free as you pay for that staff through your rates. If you don't use them, you lose out. Just remember that many of these auditors may know as much about building science as a rock, so just be aware.
My first stop would be to check your energy 'gas mileage' so to speak. You wouldn't necessarily set out to improve your car's gas mileage if you didn't already know how well it was doing, would you? If your Toyota was allready getting e.g. 35 mpg, you may not bother (prius excepted), but if it got 10 mpg, you'd be all over it.
If you are interested in checking your energy mileage, let me know; I'll help you through it. I usually start with 2 years of monthly electrical and gas (and any other energy source) useage.
I'd be inclined to replace the water heater. Also Uncle Sam will give you 30% off the price.
http://www.energystar.gov/index.cfm?c=tax_credits.tx_index
Adding a blanket will result in negligible savings.
The operational differences between a low end "6 year" and top end "12 year" retail water heater is small... about $50-$80 a year, depending on rates.
The difference between a standing pilot water heater and a PVC vented water heater is around 3%. Look at the labels... pilot water heater is ~.59 efficient and power vent is ~.62.
Some talk about standby losses, and they are real. If you use a barometric damper and regulate the losses, then they are minimized. Power vent water heaters exhaust plenty of conditioned air out the flue to get the temperature down. No way to change that.
One thing not discussed yet is combustion air.
Given 1000 btu's of energy in 1 cu. ft. of natural gas, and about 14.7 cu ft of air to support combustion... you burn 100 cu ft of gas for every 100,000 btu... 100 x 14.7 = 1470 cubic feet of air is required for combustion. Yeah, some rounded numbers.
Where does that air come from? Indoors, right?
Then where?
You have 1470 cubic feet of infiltrating outdoor air that must be heated, filtered and humidified because the heated, filtered and humidified air was just sent up the chimney. That number is for every hour the furnace runs. Don't forget about the water heater.
For reference, 1470 cubic feet is a room roughly 12 x 15 x 8.
Sealing up air leaks is pointless if your heating equipment does not have a source of mechanically forced combustion air.
That means a furnace/boiler/water heater with intake and exhaust pipes... or, a system like a "Fan in a Can" tied into the burner controls of <90% efficient appliances/power vent water heaters.
I have a NON-POWERED direct vent with a .62 EF.
Does not qualify for the federal credit, but enough to get a small credit from the gas company. Would have gotten more for a tankless.
My summer gas usage drop about 60% when I replaced it, but I also got rid of 2 furnaces with standing pilots at the same time. And replaced it with a dual fuel setup with a 97% furance.
To the OP look at your gas bill from the summer. Look at the actually CCF or therms and not the dollar amounts. That will show what the amount of gas used for the HW and cooking.
Then compare it to current bills. I suspect that it is a relatively small amount of your total usages.
You're right Bill. At least
You're right Bill. At least up here a good chunk of a gas bill has nothing to do with the actual amount of gas that is used. This where a lot of people are "duped" in thinking that with some installs they will save say 20% of their gas "bill" when in fact they might be saving 20% on their gas usage. 2 totally different things.
roger
Hmmm not sure what you are saying. I think you are confusing a reduction of the LOAD with a reduction of the bill. A 20% reduction in my gas consumption means a 20% reduction of my bill. A 20% reduction of my load (e.g. via insulation) will affect my bill a little differently due to the combustion inefficiency that must be accounted for.
Not sure what you mean when you say "up here a good chunk of a gas bill has nothing to do with the actual amount of gas that is used." Maybe you refer to e.g. a base charge, which is often a relatively small amount of a gas bill (e.g. a few bucks out of say 80 or 100).
Not sure what you mean when you say "up here a good chunk of a gas bill has nothing to do with the actual amount of gas that is used." Maybe you refer to e.g. a base charge, which is often a relatively small amount of a gas bill (e.g. a few bucks out of say 80 or 100).
Well it depends on the gas company charges.
First of all base charges are not very common anymore.
Until about 2 years ago there was a fixed charge to pay for meter reading, billing and similar fixed cost.
And there where two usage charges. One paid for the cost of maintaining the local distribution system. The other part was for the cost of gas used.
They they lumped the local distribution cost into the fixed cost.
For Nov my fixed cost was $25.23 and usage cost was $18.78.
Aslo this month the cost of gas jumped from $0.54 to $0.70. And locally the gas price is typically adjust 2-3 times a year. The cost is based on spot price, long term contracted prices, and gas purchased in the summer and stored (and the cost of storing).
In some areas the price is adjusted monthly.
And they have a request in for a fixed monthy charge increase of about 10%.
So actually CCF or therms or whatever units that you are billed in is the only practical way to compare changes in gas usage.
When I replaced my HVAC and WH I went with a dual fuel system. I was very tempted to go with electric WH and discontinue gas for about 6 months during the summer. Even with the reconnect fee the our large monthly cost made it tempting.
You nailed it Bill. Up here the gas companies must apply to the government for any increase in fuel but they do not have to apply if they increase all their other rates. Needless to say you can tell what happens.
What they lose on the peanuts they make on the popcorn.
roger
You are right on target. I sat on our local city council for a few years while we were examining nat. gas franchise information. We had an ex gas co employee who came in and explained everything to us ad naseum. Its a huge shell game. The company we were dealing with at time found it to their advantage to split up each part of the company, then sell its services to the other parts, giving them markups on just about everything on every step, from inter to intra state transport, local supply, and all steps inbetween. They also used a tiered system on their billing, the first so many therms this rate, next so many therms another, and so on, so no one could just divide out their bill by number of therms and see what the rate was.and billed an outragous amount for fixed services.
My business was on gas only in the shop, where I had two hanging furnaces. With the pilot light out in the spring and summer, my monthly bill was still over $40 per month 7 or so years ago. Found out that a large part of that was for contracts they had entered into years ago with themselves for outragous prices (since they passed through the costs, there was no incentive for them to be more frugal). The market had dropped, and they were able to roll part of those "costs" onto a fixed aspect of the bill. We and others objected, and they won in court. I had them pull the meter.
You don't need to have a
You don't need to have a powered combustion system as you ellude to. But you can control combustion air venting using motorized dampers that open when the appliance fires. They are simple and relatively inexpensive. You do have to interlock them w/ the furnace as you implied w/ your fan idea.
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>>Sealing up air leaks is pointless if your heating equipment does not have a source of mechanically forced combustion air.
Question - why mechanically forced?
danski,
Where did you get that 14.7 cu. ft. of air for each cu. ft. of natural gas consumed?
I'm guessing that he's taken
I'm guessing that he's taken the usual 10 times for combustion air(primary) and the rest 4.7 is secondary air at the hood.
roger
Over time, scale (such as lime) builds up on the bottom of the tank, reducing the heat transfer to the water.
Per a manufacturer's web site, 1/2" of scale = about a 50% increase in gas consumption.
In my area, plumbers tell me there is about 1/10 in of scale build up per year.
Some water heaters put a bend at the bottom of the dip tube to reduce/eliminate scale build up.
I question its effectiveness, but have no concrete evidence one way or the other
In my area, replacing a 15 year water heater will like ly pay for itself in less than 2 years in increased efficiency
And then be sure to use the drain valve regularly to remove scale.