What is your climate zone? Is your house tight? How tight?
Does your house run positive,negative or almost nuetral?
How do you maintain the proper pressure for your house in your climate?
How does fresh air enter your home? How does it exit?
How do you humidify or dehumidify?
“Keep the rain out.Keep the outside air out.Keep the inside air in and let the moisture out in both directions” per Lstiburek
Replies
Greetings home,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
sobriety is the root cause of dementia.
Let's try this one more time.
bump
sobriety is the root cause of dementia.
Old house. Windows rattle when the wind blows. hope to build one soon that's sealed and with a HRV.
Forrest
Forrest,
When I built the house where I live now...I could not answer those questions.
I had never heard of EEBA and I thought I was building an Energy efficient house.
I have come to learn how important it is to be able to answer all of the questions that I posted. I don't have all the answers...but I have questions. I would like to know if I am the only one at this forum that thinks about such things. I think a lot of people have figured out how to build a tight house...I am not so sure that ventilation is very well understood.
I live in a mixed Humid Climate, I intend to build to 1/3 air changes per hour and I plan to have the "tightness" verified by blower door test. My goal is to keep my house at a nuetral or slightly positive pressure at all times. I am still working on the strategy. For my climate I believe I will need a dehumidifier in addtion to my AC.
Tim and VATom and ShelterNerd can answer for their homes..can anyone else?
John
What is your climate zone? Is your house tight? How tight?
Zone 6. No. About as tight as an extra-extra-large.
Does your house run positive,negative or almost nuetral?
Dunno, I'm a homeowner. Without AC or heat my house is always 10degrees hotter than it is outside - summer or winter.
How do you maintain the proper pressure for your house in your climate?
I haven't been able to fit the cuff from the aneroid monitor around my house's arm to check.
How does fresh air enter your home? How does it exit?
Through the walls. Out the same way.
How do you humidify or dehumidify?
I live in the desert. I occasionally cook pasta which humidifies.
What is your climate zone? Is your house tight? How tight?
SF Bay area. Not sure what zone that is. No, it's not tight. At all. 1919 bungalow with no insulation. Original double-hung single pane windows. Big gap under front door, partially bridged with nail-on garage door weatherstrip. No damper in the chimney. Mail slot through the wall. I can see the light in the basement between the boards in the bedroom floor.
Does your house run positive,negative or almost nuetral?
I'd guess pretty close to neutral.
How do you maintain the proper pressure for your house in your climate?
Don't know about "proper", the pressure is what it is.
How does fresh air enter your home? How does it exit?
Walls.
Back door (open most of the time during the day).
Front door (open a lot of the time).
Bathroom windows (one is open a crack all of the time, the other is open sometimes).
Chimney
Other windows.
Floor over ventilated crawl space.
How do you humidify or dehumidify?
Dehumidify:
Open bathroom window or back door.
Fix/replace sump pump in basement.
Humidify:
Turn on shower.
Cook, especially tea or soup.
Drink lots of water.
Rebeccah
Oh you California people...you are fortunate
Your climate is pretty mild. Here in North Texas we pay a pretty high energy penalty when we open our windows. Enjoy your weather.
Homedesign,
What is your climate zone? Is your house tight? How tight?
Climate zone 4 (Central Oklahoma),Zoning depends on who's graphing... houses constructed about as tight as you can get, up too caulking studs, plates, etc. exterior tyveck wrap, radiant barrier, proper blocking throughout the frame of the home.
Does your house run positive,negative or almost nuetral?
Prefer to control with positive pressure.
How do you maintain the proper pressure for your house in your climate?
Proper HVAC and ventilation throughout home, also being very informative to clients operation of the house.
How does fresh air enter your home? How does it exit?
Intake through HVAC, fresh air makeup, exhausted through various vented areas in the home. (Kitchen, bathroom, dryer exhaust, etc)
How do you humidify or dehumidify?
Additional humidifyers attached to HVAC systems.
Maintain a 40% or so relative humidity in the homes, average bills for a 3000 sq ft home is approx $150.00 monthly, granted I do pay approx. 70% more for the set-up process but it will pay for itself within 5 years of use. the rest is money (kept) in the bank!!!!!
I think all the questions can be answered for the new house I will be building. Not sure I can personally answer them, but maybe:
Tight as you can get with the building envelope fully insulated with Icynene. Pultruded fiberglass framed thermal windows with coating to minimize heat gain (in GA).Slab on grade with infloor hydronic radiant heat, so best practices for that dictate 4000 psi slab, which is waterproof, insulated only around the perimeter here in zone 7, but we'll take it a little farther in. HRV to supply air exchanges and balanced pressure; HRV shares ductwork with traditional central A/C system and whole house air purification unit. Will need to add a dehumidifier to that here, I'm pretty sure.
Now, I have a question for you. I understand that there has been less than overwhelming success with maintaining positive pressure in houses. Do you have some good info. about that? Or is neutral the best we can actually accomplish? And, if it's a tight house with windows always closed, balanced mechanical ventilation, no backdrafting issues, etc--do we WANT to shoot for positive pressure?
And, if it's a tight house with windows always closed, balanced mechanical ventilation, no backdrafting issues, etc--do we WANT to shoot for positive pressure?
MntnBoy,
I can't say how good my info is. Here is some folksy "hearsay"
If you live in the North your house should suck and you must perfectly airseal your house from an attached garage DO NOT SUCK AIR FROM YOUR GARAGE
If you live in the South your house should blow.
John B
I think it should be neutral wherever you are and most of the time I read about problems with houses sucking too much. And it being virtually impossible for them to blow, despite the use of gadgets to try to create a slightly positive pressure.With all sealed combustion systems, no oversized exhaust/range hoods, a separate garage, the mechanical room isolated air tight slab through roof from the house airstream, Icynene insulation, fiberglass window frames, etc.--why in the world would I want to make my house here in the south blow? Even if it could be accomplished?Have you read anything much on ventilation? If not, a good place to start would be John Bower's book Understanding Ventilation. It's 400 pages or so of really good, basic info. on residential ventilation.
I am only talkin about the south here.
If you are concerned about air quality..would it not be better to be in complete control of all air that enters your house? and not as concerned with a little bit escaping? perfectly sealed is not practical
When we dive into water we humans stay nuetral or we blow a little.
We would never suck
MtnBoy,
Thanks for the suggestion...I will track down that book
My question for you: Why do you think it is better for a house in the south to be slightly negative? was it something in that book?
John B
I didn't think I said that. I believe that neutral pressure is best in every situation. But from what I understand, the efforts some folks have made, regardless of climate, to achieve positive pressure (by use of blowers usually) have met with little success.I am certainly no expert on this. The folks who regularly post under the Green section here will know about it.Good luck with your learning.
Positive and negative do not refer to any measurable difference in inside and outside pressure. They refer to whether the main vent fan blows in or out.The house my father built was as airtight as a screen door, but because we used a swamp cooler, it was a positive house.If you use exhaust fans for air exchange, you have a negative house. Air tightness doesn't matter.In this context, neutral implies no mechanical air exchange.SamT
Air tightness doesn't matter.
SamT,Air tightness does matter. Before we can control air we must first enclose air.If exhaust air is greater than makeup air then the house will become negative.Which can be a good thing in the North.Negative is a bad thing in the South because we do not want to suck warm humid air into our walls.
Exhaust fans do present challenges, but as long as we can introduce slightly more makeup air.... then we can maintain a positive pressure.
It can be done....we have the technology.
For the house I sold in January...
>What is your climate zone? Is your house tight? How tight?
Zone 4. Yes. Similar client house measured 0.035 ACH
>Does your house run positive,negative or almost nuetral?
Slightly positive
>How do you maintain the proper pressure for your house in your climate?
HVAC contractor set up system with filtered intake, dehumidifier, etc.
>How do you humidify or dehumidify?
Dehumidifier. 35%-45% RH year-round.
CloudHidden, thank you
can you imagine building a house without thinking about this stuff?
Since I really only design in one genre, it's an automatic byproduct of the design. The merit of what we built was brought home (pun intended) when we bought a 3 yo house upon moving. Normal new frame house for the area, but the difference from the other in performance is huuuuuuuuge. Temp change is felt immediately. Humidity fluctuations are constant and large, and there's no hope for controlling them. Wind makes the house creak. <sigh> I look forward to someday being in one of my houses again.
HomeDesign.
I'm not finished yet but am attempting to get neutral pressure For Minnesota's cold climate. To achieve that the standby furnace is one of the high efficency designs which take outside air in and exhaust flue gases sideways.. I've eliminated other air consumers such as gas fired water heaters and fireplaces.. When I do put a fireplace in I will ensure that it draws combustion air from outside. The Boilers for in floor radiant heat are electrically powered and operated so no air will be consumed. I will not have a stove hood so that consumer of air is not in place.. The sole remaining aplliance which uses air will be the clothes dryer.. which while it's in regular use now will quickly decrease isage.. However I've given serious thought to even replacing that item .
How tight is my home, again it's not complete yet so I don't have blower door test results.. however I took extreme care using SIP's as an insulation media and taking great pains to ensure that the joints are tight and well sealed.. all windows and doors are sealed with sprayed in foam. and care was taken to ensure good quaility windows/doors were used..
Edited 9/15/2007 2:49 pm ET by frenchy
house was build in 1902 ...
so U figure it out!
at least we don't have to worry about radon, mold or excess moisture ...
it all just leaks out!
sometimes blows out ...
depends on the wind.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa