What symtoms do you have that show you have an infiltration problem? Measuring the temp of the walls and windows sounds more like a heat loss problem. I think an exterminating co. would be more help, for the cricket problem in the basement.
I'm just moved into a new house and I would like to plug up all the air leaks. The house was built in 97 so it's modern construction. I have read that you can use an infrared imaging sensor to see which walls are colder and possibly windows also. I've also read that using smoke sticks to see if the smoke gets blown around by the drafts can he helpful. Can one of these infrared sensors be purchased at a resonable price? I have not found one on the internet.
Should I just have someone come in and do a real test using a blower door and such? If so what kind of company does this? None of the HVAC contractors I've called really even know what I'm talking about. I get the idea that they would solve my air infiltration problem simply by installing a larger unit.
As a result of plugging up all my leaks I hope to cut down on the number of spiders and crickets that find there way into my basement. How do these bugs get in anyway? In my old house I thought I had everything plugged up but even the largest of crickets still found a way in. I want to do this one right.
Thanks in advance
Rob'
What symtoms do you have that show you have an infiltration problem? Measuring the temp of the walls and windows sounds more like a heat loss problem. I think an exterminating co. would be more help, for the cricket problem in the basement.
If you have average construction or better your air infiltration should be minimal.
It really appears as though you have "modern" construction as you noted, but not "average to tight" construction.
It should be fairly easy to assess. What type of insulation do you have? Orientation of windows? Windows facing? Size of house?...etc.
Upsizing your equipment won't change the CFM of infiltrated air in your home but you can check for tightness throughout your duct system to minimize leakage there and have a number of other checks performed including
a load calculation ,which in your case, should be done
You don't need an imager or anything like that.
Shop around for a company that knows heating & air and knows what should be going on with the structure and the system.
You need a blower door test. Ask your local utility or go on the net and look for energy raters in your state. The most important holes are the attic holes. Any time you have wires, pipes, chimneys, canned lights ect. , you can seal these4 and help.
instead of spending the $ on a test, start sealing holes -- pop off the trim around windows, fill that gap with minimum expanding foam. take off elec box covers [ look for insulation behind these in outside walls ] fill gap between boxes & wall with spackling or silicone caulking, same for HVAC registers & grills. seal ALL seams, holes, joints & cracks of HVAC ductwork & equip (NOT around the covers).
My house had NO insulation on exterior fam rm wall, big hole under dbl window, around door, etc.
BUT, do not seal up the small weep holes near the bottom of brick siding! brick is pouous & the water needs to get out --
now get a blower door test, maybe.
Before you start checking the system capacity, you need to verify that the load considerations on the envelope are accurate.
A blower door test may not be needed at all and certainly won't be needed until you figure out what system requirements are needed to satisfy the load on the house.
I'm told the unit is a bit over sized right now so i have no doubt that it can heat and cool the house but I just want to make sure everything is air tight. Maybe I just like my stuff tight, I don't really know what motivates me sometimes. I do plan to touch up the caulk around the windows, wires, pipes, outlets etc.,but I figured if there was a way to detect what areas are a bit cooler in the winter or actually be able to see air movement and direction I could be find all of the holes. In my old house I obsessed over plugging every hole I could find, but there was still a slight draft comming from the utility room that I never found.
Thanks for all the advice and I will seal all the holes to the attic also. In my old house I could tell that the air was entering in from the basement and heading out through holes to the attic and I seem to feel this slight draft in the new house. I would to lick it for good.
Most homes infiltrate a little excess fresh air during cold windy weather. MY bet is that you are not getting the necessary air change rate for good air quality during the mild seasons when not windy. Best to setup proper ventilation before stopping infiltration. All homes need 50-100 cfm of fresh air to purge pollutants and provide oxygen when occupied. How much are you getting now?
If the windows are dry during the heating season and you do not need a humidifier, you are ok during the winter. But need make-up air during the spring, summer, and fall. Suggest proper amount of make-up air first. Than have a ball and tighten everything possible. Also remmeber clean air and <50%RH.
Before making your home more tight, first rid it of all pollutants. Anything that has a chemically induced odor is a severe pollutant.
This reminds me a bit of the thinking during the Black Plague of the Dark Ages. The royalty all shut themselves up in their castle compounds which actually caused the disease to spread more quickly due to lack of dilution by fresh air.
Training is important!
Practical Training is a must!
Here is an idea which might draw some criticism from the professionals here. If you do not already have a fresh air inlet, and add one, then you will change the air dynamics so it will have a greater tendency to flow outward rather than inward. It would seem this would reduce the air infiltration via ceiling-attic penetrations (e.g. typical cannister lamps) which is one of your more "harmful" infiltration sources -- at least in my area.
It very well could be that you seal a lot of openings, thus causing an increased need for a fresh air inlet. While this is ironic, the inlet air will always have the chance to go through your filtration and conditioning. That's gotta beat random attic air every time<g>. The motto of many experts is "Build it tight and ventilate right".
I have trouble with the argument that you should seal attic and other penetrations "instead" of having a blower door test. The sealing process will be labor intensive if it uses a lot of caulk, you can DIY but cannot buy a lot of labor for that price. And if you go the route of buying new airtight cannister lamps, again it's either DIY or spend a lot of money. Usually a blower door test will tell you do seal more, anyway. Just that with the testing you will understand where you started out and where you ended up.
House leakage is likely to be measured as a surprising number of square inches total leakage. Since a cricket only needs a tiny fraction to crawl through, I would think you could seal very well and still not get all the holes bugs come through. I agree an exterminator would be the method unless you can find and fix some obvious bug holes.
Best of luck -- P.Student
Boy thats an understatement!Originally posted by perpetual_student
House leakage is likely to be measured as a surprising number of square inches total leakage.
A company I used to work for did blower door testing. I was in a few houses while they were being tested, that looked well constructed, that I thought wouldn't be to bad, but in reality were leaking so bad it was almost like having a 10'x8' section of the outside wall knocked out!
My two cents. I also think it is a good idea to know where you are starting from and where you end up as far as infiltration goes. A blower door test in conjunction with an infrared camera is a cool way to get an idea of infiltration rates and leakage paths. IMO, a blower door test can give you a better idea of infiltration when it comes to doing your load calcs on the building rather than taking a guess for infiltration load. You can also operate the blower door and then "see" where air is coming from. There could be huge by-passes in wall cavities, through structural return systems on forced air units, and in bulkhead areas. I agree that sealing high and low are the best places to start and not on the neutral pressure plane of the home. You have to seal around a lot of windows to equal the open wall cavities into an attic from typical bulkhead construction. Knowing where you are starting can give you a better idea of when to stop so you don't get it too tight and start messing with IAQ. Like Teddy Bear said, ventilation is important, but you may be able to cut infiltration in half - and, in turn, reduce comfort conditioning costs and still be fine.
Another point is in your duct system but not related to leakage. If you don't have a return in each room that can be closed off using a door ( except for bathrooms) then you have an infiltration problem when the doors are closed to those rooms. If you are putting 160 cfm supply into a room and the door is closed and it has no return that room is now in a positive pressure and pushing air to the outside any where it can. The main area where the return is now missing that 160 cfm and goes into a vacuum pulling in air anywhere it can. Multiply that by four bedrooms. Most of your home is in a vacuum. This only relates if you have that type of return duct system.Originally posted by 7X
My two cents. I also think it is a good idea to know where you are starting from and where you end up as far as infiltration goes. A blower door test in conjunction with an infrared camera is a cool way to get an idea of infiltration rates and leakage paths. IMO, a blower door test can give you a better idea of infiltration when it comes to doing your load calcs on the building rather than taking a guess for infiltration load. You can also operate the blower door and then "see" where air is coming from. There could be huge by-passes in wall cavities, through structural return systems on forced air units, and in bulkhead areas. I agree that sealing high and low are the best places to start and not on the neutral pressure plane of the home. You have to seal around a lot of windows to equal the open wall cavities into an attic from typical bulkhead construction. Knowing where you are starting can give you a better idea of when to stop so you don't get it too tight and start messing with IAQ. Like Teddy Bear said, ventilation is important, but you may be able to cut infiltration in half - and, in turn, reduce comfort conditioning costs and still be fine.
the thermal scan is very effective, even
more so when used in conjunction with
a blower door.
Cost would be a concern.
Get your home and duct work tested
with a blower door.
Identify the leakage areas to be sealed,
you can use a lot of calk and miss the
leakage areas if you do not know where
they are.
House leakage is identified by depressurization
test with blower door, duct leakage can also
be identified by pressurizing with blower door.
I use smoke sticks for both types of testing
to show homeowner/builder/havc installer
where leakage areas are.
Best of luck.
BTW the bugs come in everywhere.
In my area ants are a big problem.
Caulking plumbing penetrations under
sinks is a start!
Thanks for all the comments. I think I will have a blower door test done just so I can see for sure what I'm dealing with.
Also thanks for the chemical fume reminder. I plan to keep the chemicals in the garage in this new house. I guess there are possibilities of some leakage from there also but the blower door test should reveal that.
In regards to the bugs I just don't understand how such a large bugs can get in through a hole that I can't locate with my eyes. Do ya think an exterminator can actually find the holes where the bugs come in or will he just wage widespread chemical warfair on the bugs.
Thanks again
Rob
Yes , do some searches on the internet, for bug control. They have all the research on how bugs enter the home and how to prevent it.
You got alot of advise on air infiltration, but you havn't said what the problem is, or what effects on Air
quality that you are experiencing? You can't make it air tight, enless you seal all the doors too! My point is your striving for something beyond what is required nor even possible.
[Edited by Chill on 04-19-2005 at 10:47 PM]
I don't really have a specific issue to solve as far as indoor air quality goes. I just thought that it was best to have an air tight house so I can control the infiltration myself. It's a new house and I want to know what I'm dealing with. It's just for piece of mind and the knowledge could come in handy in the future.
My doors and windows are pretty tight so I don't expect much infiltration there. Also it's quite easy to tell if they are leaking. I'm more concerned about the mystery leaks.
Thanks
Rob
I agree with Robo. Extreme tightness is part of the growing "mold remediation" problem we seem to be taking all of the heat for.
And the point about the blower door test is a good one because it is an accurate test of the volume of entering air.
I still like the idea of fresh air either through envelope leakage or forced air entry though, as long as it's not too excessive.
Extreme tightness has nothing to do with the mold problem. Building homes wrong has everything to do with the mold problem. Every home should be built as tight as possible and mechanically ventilated. There is no excuse for building code built crap in this country, that is the majority of new construction.
A homeowner's opinion: It seems a whole lotta builders have no concept of dedicated ventilation. In the days of loose construction, the natural infiltration would be within ASHRAE recommended levels (or sometimes much higher). But if these same people start building tight houses, now they need to get educated on ventilation. Not all of them have the education that is needed to deal with tight, that is proper, building methods.
I tried to find out where the Texas mold problem was coming from, and in most if not all cases that I read about, there was a gross defect in construction. For example a leaky window or pipe in the structure. Tight construction really has nothing to do with that. However for some mobile homes they could grow mold without such a leak, by means of humid air inside and something below the dewpoint, e.g. a cold air duct blowing onto a surface.
But even in houses with no mold, I would be wary of excessive humidity and lousy indoor air quality. When builders understand the need for ventilation, things ought to change for the better.
Hope this helps -- P.Student