Winterize your home - how much do air leaks cost?

[kristopher]

"Lets look at an example close to home: my home. I live in Vancouver, BC, Canada. My home has about 230 m^2 of heated area with 2.2 m ceilings. As such the volume of air in my home is about 500 m^3. The density of air at 20C at sea level is about 1.275 kg/m^3 so my home contains about 640kg of air. The specific heat of air is about 1kJ/kg/C. That means to raise the temperature of 1kg of air by 1C requires 1kJ (kiloJoule) of energy. The average outside temperature in Vancouver measured over an entire year is about 10C. Therefore, to raise the temperature of the air in my home from 10C to 20C requires 6.4 MJ (megaJoules) of energy. If air infiltration is resulting in 3 times the recommended ventilation (ie 1 air change per hour instead of the recommended 0.35) then the air in my home is being changed an additional 15 times per day or about 5500 times per year more than necessary. At 6.4 MJ of energy per air change, that amounts to 35 GJ (gigaJoules) of wasted heat per year.

But that's not all. My natural gas furnace is over 15 years old and has an efficiency of only about 60%, so it requires 58 GJ of natural gas to produce 35 GJ of heat in the living space of the home. This ammounts to about half the natural gas I consume in a year. It costs me about $14.50 per GJ of natural gas, so my potential savings are about $840/year just by sealing my home better without adding any additional insulation, or replacing my furnace. Adding insulation and replacing my furnace are worthwhile too, but they require a much greater capital investment for probably about the same return."

Source and more: http://www.iwilltry.org/w/index.php?title=How_to_weatherproof_your_home

[4dsc]

1. Have no idea what you're talking about

but I winterize my home every year to prevent air leakage and have been doing since 1980..

[liberal N proud]

2. We installed a new 90% efficiency furnace

This unit draws the combustion air from outside, not from the house as most traditional units have in the past.
We have noticed there are no more drafts or cold spots in the house.

What does that mean? First of all the air used for combustion is never cycled through the house. Cold air is brought in through a tube to the combustion chamber and exhausted right back out through another pipe. If you are using the air in the house for combustion, it must be replaced.

Air replacing the combustion on an older furnace from the room is drawn through the house causing replacement (cold) air to be pulled through cracks and openings. This causes the drafts and cold spots in a house. We are not experiencing cold spots or drafts.

Energy bill has dropped as well because the new unit is a 2 stage unit and until the yesterday (temp at 1 Deg. F w/ 50 mph winds), the furnace has not run full power, saving $$$.

[kestrel91316]

6. My sister replaced the furnace in her 1920s WI home 10 yrs ago,

and that made a HUGE difference in how cozy the house is. NO more leaky windows. There is a PVC pipe outside that draws the combustion air, otherwise you can't see any difference. REALLY efficient.

[madokie]

8. I noticed a big difference when I connect the inlet air to the outside

on my first pellet stove but this one I have now even though it has a place to connect the pipe its not going directly into the firebox. It just dumps into the back of the stove and the stove has louvers on the back and on each side so their saying I can connect my stove to the outside for combustion air is a big assed lie. Actually what happens when I did connect it to the outside is its like openning an inch and a half hole in the wall.

I've thought about contacting the manufacturer about that little tidbit and see if I can get a refund or swap for one that will. Like you said it made a lot of difference when I connected our last pellet stoves combustion air to the outside. If anyone has any ideas about what I said about contacting the manufacturer, please let me hear them cause it pisses me off that they outright lied about that. Maybe most people wouldn't notice but I did.

[liberal N proud]

10. Definitely contact the manufacture

In todays green world, we need to worry about the energy used.

[keith the dem]

3. I'm an engineer and architect

who frequently deals with energy issues. I doubt your getting that kind of infiltration on most days unless you live in a very windy area; however, you certainly could get that kind of infiltration on a windy day. That said, sealing up the cracks is probably one of the most cost effective ways to save energy. A programmable thermostat and a war comforter is probably the most cost effective energy measure.

If you have the money, changing the boiler would be the best place to put the money.

A word of warning! don't believe the replacement window salesmen. If you already have storm windows, you will not save much energy. Some replacement windows may actually use more energy than the combination of a wood window and a storm window. Windows are very costly and even the best may not last long enough save the energy dollars to recoup the investment.

Use the money instead to improve system controls, seal cracks, and insulate. If you have the money, invest in a high efficiency heating system.

[Citizen Number 9]

7. Do you mean 0.35 changes per hour as opposed to 1.0?

"I doubt your getting that kind of infiltration on most days"

How does a homeowner know what his "air changes per hour" actually is?

[keith the dem]

9. Air changes per hour

is only a rough estimate used to determine the sizing of heating equipment and has little use in determining energy usage. We use the crack method to do the same thing; however this is still a rough estimate.

Energy audit people will do a pressure test on a building to determine the rate of leakage. This again is probably more useful to find where the leaks are so they can be sealed, rather than to determine energy usage. To do an energy usage estimation, a whole list of variables would need to be considered such as wind speeds over time at different temperatures (inside and out), wind direction, etc.

Because of the complicated list of variable, energy estimation is a bit of an art form. My way of doing it is to do the calculations and compare them to actual energy usage. The actual energy usage will often be half of what the straight calculations determine.

Don't assume that infiltration is always a bad thing. I started my engineering career after the first energy crisis when ventilation rates were drastically reduced. A whole series of deleterious health problems resulted. Ventilation is needed. The best way to do this is to have a tight house with some sort of fan powered heat exchange unit to provide controlled ventilation air while recovering the heat from exhausted air. If you don't have that, be sure that your house is not too tight. Allow some infiltration and worry about the temperature control, insulation and equipment efficiency first.

[Citizen Number 9]

11. Okay, so you can get someone to come out and

do a pressure test on your residence to see how leaky it might be?

Got any idea how much that might cost someone these days?

Seems like the Utility company might want to offer that service, or subsidize it, even.

[Fledermaus]

12. This is how I did it.

I use one of my bath room fans and a fan speed/timer.

Multiply the square footage by your ceiling height. This will give you an idea of how many cubic feet you have in your house. Divide this by the number of cubic feet/min your bath room fan runs at. This will tell you how many minutes your bathroom fan will have to run to vent your home.

1500 X 8 = 12000

12000 / 100 =120min

Running the fan for 5 minutes every hour will vent the house one time. The amount of money you spend heating or cooling that amount of air is meaningless.

http://www.tamtech.com/store/airetrack-fan-control,Product.asp

[keith the dem]

13. Look up energy audit in the yellow pages

If you live in the Philly area, there is one who I would strongly recommend. Often Utility companies will do this; however sometimes the contractors they use are horrible. I was expert witness in a lawsuit where a utility's contractor sealed up vents needed to control moisture within the house (attic and crawl space vents). The house had to be demolished because of the mold that resulted.

By the way, moisture control and mold is another reason to be very careful in sealing up a house!

[HillWilliam]

4. It's also the little things that count

We've knocked a pile (about $75/month) off our heating bill with two simple things: the first being obvious, using those heavy insulating window-panels we got from Lowe's; the second was not so obvious, being to insulate every light-switch cover and wall recepticle. Did you know those alone can add up to two open windows? I didn't. I do now. My electric bill shows the difference. That latter cost less than $40 to do the whole house worth and I got that back the first month of serious heating.

[kestrel91316]

5. I just replaced the weatherstripping at the front and back doors of my business

(the old stuff wasn't doing much) and have noticed a big difference in the cold drafts near them. So I did it to my apartment front door and, lo and behold, same success!

Better news: an old friend of mine is going to pull out sheetrock and throw some insulation batts into 25 ft of wall at the clinic (where there is ZERO insulation between studs currently, lol) and redo the sheetrock. And he's doing it for COST, and I can pay by crediting his account so I can barter care for his kitties!! He also will barter for any other projects I need done around the place. But the insulation project is HUGE for me.