View Full Version : Decisions about which ventilation to choose.
02-24-2006, 11:04 AM
I just read Teddy Bear's answer on EAC subject. Great info everywhere on the boards and i'd really like to pick your brains.
"Ventilate" is crucial, I was planning on doing that with my 2 story 1500sf total home, but what to do when there is too much "ventilation" to begin with in terms of air infiltration? I was concerned about air quality and started the quest for an ERV HRV but the low humidty levels in my house (30%) give or take throughout the day tells me it's too drafty and to not use an HRV. Well, I still wanted good air quality, so i'm installing a dedicated air purifier Lifebreath TFP and will go from there. I may need two units, don't know how to configure it yet... I will also try and seal up the house but it's all finished and sheetrocked in every inch of the house. The only place left is the outside foundation which is 3feet high that will get covered in a stucco or some kind of insulation to further reduce air infiltration. I will also caulk the trim, outlets, switches, everything i can do to reduce the infiltration. I doubt all that will do anything for the 30% humidty levels but I must try.
So, what is one to do if they don't have a sealed house regarding "ventilation"? I still would like very clean air and the ventilation options call for a sealed house, but the filtration options... I'm not sure.
02-24-2006, 11:55 AM
What's wrong with a home that breathes enough during cold weather? Typically 50-75cfm of fresh air purges pollutants and renews oxygen. The 50-75cfm fresh air leaking into home cost <$75 per year to heat for the year @ 7,500 degree days. Spending a lot of money to tighten the home enough to require HRV to save half the energy does not have any pay back. Keep in mind that during the rest of the year, you need mechanical ventilation when the building is occupied. Because of the low energy content and exhaust air requirements of clothes drier/kitchen hood/bath fans, simple make-up ventilation makes the most sense. Make-up air filtering(merv 10) as small advantages. Extreme air filtering has little benefit for air quality most dust settles before getting to an air filter. Maintain <50%RH to control mold and dust mites during the wet time of the year. Loading a home with mold and d/m fecal pellets during summer over-whelms any winter ventilation/filtering stategy. Fresh air ventilation during occupancy and <50%RH are the biggies. TB
02-24-2006, 06:36 PM
I think I understand what you mean. Thank You. I just don't know how much I'm losing to infiltration. I'm also a slave to mother nature and wind speed/infiltration isn't under my control. Not a huge problem, I am lower than 50% humidity but it may be too low. As much (or as low) as 23% during the night. I may need to run a humidifier.
I have a lot of dust as well. It may be from the infiltration, I don't know. That was the reasoning for the purification system, but i also agree with your assessment of the dust having to be in the air to be cleaned. Since my current return filters are dirty when replaced, I think the HEPA filter may help and not hurt. (hopefully). I was also planning on running if... a dedicated system 24/7 if possible.
The way I came into the air filtering system was looking at an HRV with a HEPA attatched and researching from there took me to where I am now. It's never ending. I cannot stress enough how you need to educate yourself first before getting help because the contractor I talked to about installing the HRV was ready to install it had I not researched more. Could you imagine me putting it in with a low of 23% humidty already? I'm now rambling on about this, but it seems as I'm asking a lot of questions, but I'm just showing that you can't really rely on one person's/contractor's opinion. Hate to say that with a board full of contractors. I'm sure you understand, what I'm saying isn't to ridicule the pros, but you don't know what to do as a HO.
Five years ago when I did a total rehab of my house I trusted the HVAC guy, but now changed over to hot water baseboard because I'm not happy with the forced air heat he installed. He seemed like a nice guy, knowledgable, but the job wasn't done right. It took me 2 years to figure that out.
When I learn enough of what i need, I may ask here for some pros in my area. The Yellow Pages just don't cut it, I think. thanks again.
02-24-2006, 06:48 PM
Also... Re This comment "Fresh air ventilation during occupancy and <50%RH are the biggies. TB"
What kind of 'Fresh air ventilation', the infiltration I'm getting or something else?
02-25-2006, 10:06 AM
Infiltration only works with cold weather and wind. Simple mechanical for the rest of the year. A fan in a box blending fresh air with house air during occupancy is the simplest. Several are availablewith filters, like Filter Vent. Fresh air intake on cold air return with a timer on the fan is another. In dry climates, a bath fan exhausting when occupied is great. The deluxe equipment for green grass climate incorporating dehumidification is like Ultra-Aire includes an occupancy timer and lesser Aprilaire. TB
Originally posted by cissado
I'm now rambling on about this, but it seems as I'm asking a lot of questions, but I'm just showing that you can't really rely on one person's/contractor's opinion. Hate to say that with a board full of contractors. I'm sure you understand, what I'm saying isn't to ridicule the pros, but you don't know what to do as a HO.
Yes and this is why people go to other doctors to get a second, third, and fourth opinion.
02-27-2006, 10:08 AM
start by changing your filters MORE often! If you can see dirt, you are LATE.
next, change to a 5" thick filter.
install good weatherstripping on doors & windows.
install good storms
apply mastic to all HVAC ducts & plenums at joints & seams.
next, seal around penetrations = boxes, HVAC boots, pipes.
caulk around all trim, including above & below baseboards, all wall & ceiling joints.
02-27-2006, 12:15 PM
Thank you. I started caulking and sealing yesterday. It's a bigger job than I thought it would be, but it's going well. The only problems I'm having is the insides of the electrical boxes. They seem too deep to get into and seal.
Anyway, after reading here a bit more, I think my ducts may need some sealing as well. I've located a contractor from the National Comfort Institute website, and after looking at their procedures, i'm confident they'd do a thorough job for me. I want to seal up some stuff before bringint them over.
This is what I ultimately want. Wether they can do it, or partially do it and refer me to someone else...
Not in any particular order...
Blower door test
Duct (or system) balancing
system design flaws and possible fixes.
I'm headed in the right direction. Thanks again for all the replies.
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