Common Myths About Homes

General Inspection Topics General Inspection Discussion
1

Would like to share this with everyone interested.

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Fact vs. Fiction…

Common Myths about our Homes

Myth #1: Dry indoor air in the winter is caused by forced air heating systems and a humidifier is the answer.

Fact: Dry indoor air is caused by thousands of tiny holes in the outside walls and ceiling of your house. Seal the holes, and your indoor relative humidity is usually quite comfortable given normal levels of cooking, cleaning and bathing - without additional humidification. In fact, additional humidification can lead to condensation in the exterior walls and microbial growth in the ducts.

Myth #2: **Fiberglass batts are an effective insulation product for walls and ceilings. **

Fact: Fiberglass batts are almost impossible to install without leaving compressions, gaps and voids, which cause extensive heat loss. One of the reasons fiberglass is so cheap is because installations are usually rushed. Also, fiberglass offers virtually no resistance to air flow leading to extensive heat loss through leaky exterior walls.

Myth #3: Traditional framing at 16” OC (on center) is better than 24” OC framing because you get a stronger house, and there are no unsightly waves in the sheetrock on the exterior walls.

Fact: 16” OC framing with 2x4’s has been the standard for years but puts more wood in the wall (up to 25% of the wall), and wood is a poor insulator. 24” OC framing with 2x6’s produces a very strong house and leaves more room for insulation. Upgrading to 5/8” sheetrock (instead of ½”) will prevent waving and reduce sound transmission.

Myth #4:There is nothing wrong with the standard practice of running air ducts in unconditioned basements and attics.

Fact: Testing reveals that forced air systems in the northeast typically leak 20-40% of the air they carry. This leads to much wasted energy, if the ducts are outside the conditioned envelope, and can lead to the distribution of insulation particles, moisture, radon, and mold spores throughout the house.

Myth #5: Natural draft water heaters can be safely used in any home.

Fact: The safety of natural draft combustion appliances is dependent upon the air pressure relationships within the house and between the indoors and outdoors. These pressure relationships can be dramatically affected by range hoods, dryers, and bath fans. Every combustion device should have a dedicated source of combustion air to prevent the backdrafting of combustion by-products, such as carbon monoxide, into the living environment.

Myth #6: **An air-tight home is dangerous because it creates moisture problems and can lead to sick building syndrome. **

Fact: An air-tight home eliminates uncontrolled air infiltration into the exterior walls, which is the real cause of both moisture and microbial problems. Only in an air-tight home are the occupants in control of the air, heat, and moisture flows, allowing for the controlled introduction of fresh air 24/7/365. A home with leaky exterior walls will allow excessive uncontrolled air infiltration in the winter, leading to heat loss and dry air. In the summer, even leaky exterior walls will not admit adequate fresh ventilation air (smaller temperature differences than in the winter create lower air pressure differences, with little air leakage through the outside walls), contributing to stale air and the accumulation of indoor contaminants.

****Myth #7:Oversized heating and cooling equipment is better for your home because it gives you reserve capacity.

Fact: Oversized heating and cooling equipment will not be able to properly control the temperature of the conditioned space because it produces more heating and cooling than the home needs. The unit will cycle on and off frequently (short cycle), continually overshooting the desired set points, and costing more to operate. Short cycling on the cooling side reduces the unit’s ability to remove moisture, leading to air that is both cold and damp.

****Myth #8: Replacing your single-glazed windows with double-glazed can save you up to 50% of your heating bill.

Fact: Your savings will depend on the amount of glass surface area in your home in relation to the size of your home. A typical home will see savings more like 20%. If the windows were poorly installed, then air infiltration around the windows can be a significant energy loss, and proper air sealing will save more energy.

Marcel :slight_smile: :slight_smile:

2

Looks like facts str8 outta the foam insulators bible…be careful

3

Actually it came from this link if you wish to explore some more.

http://www.bpcsbuilder.com/Building_science.htm

I thought it to be fairly good information.

Marcel :slight_smile: :slight_smile:

4

Fact: Paragraphs are our friends. :smiley:

Myth #1: Dry indoor air in the winter is caused by forced air heating systems and a humidifier is the answer.

Fact: Dry indoor air is caused by thousands of tiny holes in the outside walls and ceiling of your house. Seal the holes, and your indoor relative humidity is usually quite comfortable given normal levels of cooking, cleaning and bathing - without additional humidification. In fact, additional humidification can lead to condensation in the exterior walls and microbial growth in the ducts.

**Myth #2: Fiberglass batts are an effective insulation product for walls and ceilings. **

Fact: Fiberglass batts are almost impossible to install without leaving compressions, gaps and voids, which cause extensive heat loss. One of the reasons fiberglass is so cheap is because installations are usually rushed. Also, fiberglass offers virtually no resistance to air flow leading to extensive heat loss through leaky exterior walls.

**Myth #3: Traditional framing at 16” OC (on center) is better than 24” OC framing because you get a stronger house, and there are no unsightly waves in the sheetrock on the exterior walls. **

Fact: 16” OC framing with 2x4’s has been the standard for years but puts more wood in the wall (up to 25% of the wall), and wood is a poor insulator. 24” OC framing with 2x6’s produces a very strong house and leaves more room for insulation. Upgrading to 5/8” sheetrock (instead of ½”) will prevent waving and reduce sound transmission.

**Myth #4: There is nothing wrong with the standard practice of running air ducts in unconditioned basements and attics. **

Fact: Testing reveals that forced air systems in the northeast typically leak 20-40% of the air they carry. This leads to much wasted energy, if the ducts are outside the conditioned envelope, and can lead to the distribution of insulation particles, moisture, radon, and mold spores throughout the house.

**Myth #5: Natural draft water heaters can be safely used in any home. **

**Fact: **The safety of natural draft combustion appliances is dependent upon the air pressure relationships within the house and between the indoors and outdoors. These pressure relationships can be dramatically affected by range hoods, dryers, and bath fans. Every combustion device should have a dedicated source of combustion air to prevent the backdrafting of combustion by-products, such as carbon monoxide, into the living environment.

**Myth #6: An air-tight home is dangerous because it creates moisture problems and can lead to sick building syndrome. **

Fact: An air-tight home eliminates uncontrolled air infiltration into the exterior walls, which is the real cause of both moisture and microbial problems. Only in an air-tight home are the occupants in control of the air, heat, and moisture flows, allowing for the controlled introduction of fresh air 24/7/365. A home with leaky exterior walls will allow excessive uncontrolled air infiltration in the winter, leading to heat loss and dry air. In the summer, even leaky exterior walls will not admit adequate fresh ventilation air (smaller temperature differences than in the winter create lower air pressure differences, with little air leakage through the outside walls), contributing to stale air and the accumulation of indoor contaminants.

Myth #7: Oversized heating and cooling equipment is better for your home because it gives you reserve capacity.

Fact: Oversized heating and cooling equipment will not be able to properly control the temperature of the conditioned space because it produces more heating and cooling than the home needs. The unit will cycle on and off frequently (short cycle), continually overshooting the desired set points, and costing more to operate. Short cycling on the cooling side reduces the unit’s ability to remove moisture, leading to air that is both cold and damp.

Myth #8: Replacing your single-glazed windows with double-glazed can save you up to 50% of your heating bill.

Fact: Your savings will depend on the amount of glass surface area in your home in relation to the size of your home. A typical home will see savings more like 20%. If the windows were poorly installed, then air infiltration around the windows can be a significant energy loss, and proper air sealing will save more energy.

5

Joe T., pardon my French here, but did I do something wrong in this post.

Thanks

Marcel :slight_smile:

6

No, you probably copied this from another website, right? Well our message board does not bring the formatting over when coping from one website to another. I normally past anything I want to post into Word first and format as plain text then copy it over to the website for posting. Just looks better. :smiley:

7

Thanks Joe T., never imagined it would make a difference.

Sorry about that.

Marcel :slight_smile:

8

I agree with all of them except;

#2 is a little hyped. There are varuios types of insulation on the market and they all have their proper applications. The problem starts when a particular insulation product is beleived to be good for all applications and used in placed where perhaps a different product is better suited.

#3 Insulating a 2x4 at 16 O.C.and adding 1.5" or more of rigid board insulation will perform better from an energy stand point than 2x6’s on 24 O.C. Yes, a bit more wood.

9

Would not spray foam be the ultimate and easiest… Cookie

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Spray foam is certialnly easy to apply. It’s also one of the most expensive of the common insulating materals. Personally I think spray foam is one of the “over used” products that was mention before. I seals against air leakage great esp. in odd places. However during a reno I would much rather run in to a different insulation than spray foam.

A friend of mine had his entire attic flloor spray foamed and thouight it was great. Now he want to convert the attic into a conditioned living space. Can you see the problem?

11

Paul anyone that would have their attic floor insulated with foam must have been misinformed, the proper installation should have been the roof rafters and under side of the decking, after that any roof vents such as soffit, gable or ridge vent should have been cosed, thus making the attic space a conditioned space.

12

Yep, now he has to spray the roof. ha. ha.

Marcel :slight_smile: :wink:

13

I tried to tell him at the time but he is a little stubbon. He’s a laywer actually.

14

Marcel, Not only can he not reuse the insulation by simply moving it from the attic floor to the roof deck, but even with supply and return ducts he will have a very hard time stabilizing the temp of this space with the rest of the house. Due to the rafter depth and head height, the attic floor will still end up having a higher R-value.

15

Cheaper to put in electric Heating and a wall ac unit … Cookie

16

I would imagine at this point that the original attic ceiling was sprayed to achieve a R-38 min. and R-48 max. and continuing to spray the roof rafter spaces with the equivalent, would make that space pretty tight, and may require some ventilation.
Since all the gable vents and eave vents by now have been blocked, make-up air for the ventilation might be necessary.

You basically have created an igloo at this point with this scenario.

There is a design for air to air systems for this type of scenario, and actual vents to the exterior are installed in the exterior walls close to the ceilings, to actually let fresh air in to make up for the tightness of the building envelope.

Marcel :slight_smile: :slight_smile:
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17

Ummmm…so no “real” moisture gets in except through the air? I have a big problem with that statement.

I have seen plenty of “real” moisture problems in fieldstone basements that are not related to the seal on the windows or doors, etc.

18

Marcel,

To make things worse, the house is actually a stone century home. Absolutley no insulation in the walls. 1.5’ of stone, strapping and lath and plaster. Oil heat.

An what does he do? Pulls out all the old attic insulation (blown cell) and spends $3500 to spray foam the attic floor. :roll: Right over all the cloth insulated wiring.

This is one of the reasons why I think some products, spray foam, are over used. Now the next owner of that house has a lot more work to do to correct this error.

19

Unreal, I would not want to be the next owner.

I wonder who is consulting him into doing that mess?

Marcel:)

20

There are half-truths in every one of thoes alleged “Facts”.

Just as with the IR photo from their web site: There is over 90% of that photo that is not “heat loss” (which they are calling temperature loss).

What is temperature loss?
Temperature is a measurement of molecular movemet, not a unit of energy.