Now that I fixed the water........ :-)
I want to fix the poor air quality in the house. The house is about 15
yo and is an r2000 house--unfortunately it is sealed tight and no air
gets in (not even a roof air system). There is no ductwork. We all wake
up every morning sneezing and runny noses.
Could someone explain approx how to go about putting in a central
system that would clean the air? How much would this cost(I'm
Or should I just buy a HEPA filter for each bedroom? Any advice or
experience would be greatly appreciated.
THanks in advance
What's going on here? An R2K house with 1.5 ACH max at 50 Pa leaks about
1.5/20 = 0.075 naturally, vs 0.7 for an average US house, so a 2400ft^2x8'
R2K house would have 0.075x2400x8/60 = 24 cfm, vs the 15 cfm/occupant ASHRAE
standard. Maybe this house is tighter, or Kris doesn't use the exhaust fan.
Surveys show that R2K people are happier and healthier than others, but some
don't realize they need positive ventilation. Where do all the sneezings and
runny noses come from? Dust, mold, formaldehyde?
Excessive humidity would likely be a problem in an overly airtight or
under- ventilated house, given Andersen's estimate that a typical family
of 4 evaporates 2 gallons per day of water inside a house. We might open
upper and lower windows when humidity increases?
Smart house ventilation might use the lowest-energy-cost strategy
among several, based on the needs of the house and the weather:
1. Run a dehumidifier in the basement.
This would provide useful heat in wintertime, but it might be cheaper
to bring in cold outdoor air and provide some extra non-electric heat
for the house.
2. Air condition the basement in wintertime, with the cold side of
a window AC in an enclosed basement stairwell and the warm side
in the upstairs living space.
This could also provide wintertime heat, but it might be too loud.
3. Move basement air outdoors and outdoor air into the basement.
Like the Humidex, but with little heating penalty in wintertime,
if the cold air stays in the basement.
We could also store coolth in the basement this way in summertime,
below the comfort temp, and circulate air between the basement and
the living space during the day to keep the living space cool with
no ventilation to the outdoors.
4. Move basement air outdoors and outdoor air into the house.
On a warm dry winter day...
5. Run an air conditioner in the house.
If the house is too humid and outdoor air is too hot or more humid.
If indoor and outdoor humidity ratios were equal, we might ventilate with
outdoor air to bias the house temp warmer in winter and cooler in summe
within comfort zone limits to store more useful heat and coolth in the
thermal mass of the house. If the air temps were equal, we might want to
keep the house RH closer to 40 than 60%, storing dryness in the house
They use a lot more electrical energy than Envirosept units:
Aqua Air Technologies, Inc. 3137 Cabin Run, Woodbine, MD 21797
800-854-5126 Fax: 800-489-4186 firstname.lastname@example.org
You can make an inexpensive standalone version by duct-taping
a 20" square filter to the suction side of a 20" window box fan.
The R2K spec is now mostly performance-oriented. It says what needs to happen
vs how to achieve it. An exhaust fan in a somewhat air-leaky house can be
a lot less expensive than an HRV in a more airtight house. A 2400ft^2x8' R2K
house that leaks 1.5 ACH (480 cfm) at 50 Pa (0.2" of water) might be vented
easily with a small exhaust fan with a one-day damper.
That says "R2000 homes use HRVs." It does not say "R2000 homes must use HRVs."
Some use exhaust fans ("a mechanical ventilation system") instead. They must
have a min capacity and at least two speeds and a manual switch to turn them
on that can override other controls. Some R2K houses in Ontario have had air
quality problems because the owners didn't use the "principal exhaust fan,"
mainly because nobody told tham that was needed.
You might look at the R2K standard itself, and the standards it references...
5.2.1 Design, Installation and Balancing of Ventilation Systems - Mechanical
ventilation systems shall be designed, installed and balanced in accordance
with CAN/CSA-F326-M91 Residential Mechanical Ventilation Systems...
The National Building Code of Canada 1995 Section 18.104.22.168
prescribes that every dwelling unit that is supplied with electrical power
shall be provided with a mechanical ventilation system complying with:
CAN/CSA-F326 or the balance of Section 9.32.3
The following paragraphs describe the types of ventilation systems and their
Firstly, all types require the "room count" method of determining a Total
Ventilation Capacity (TVC). Using a combination of continuous (principal)
and intermittant (supplemental) fans, the mechanical ventilation system must
be capable of operating at the TVC.
Type 9.32.3 (NBC95)
9.32.3 requires that a Principal Exhaust fan must provide at least 50% of
TVC. A fan capable of supplying 75% or more of the TVC must have a control
to allow switching to 45 to 55% of TVC.
If this fan exhausts only the kitchen, a vented range hood is not required
but bathroom fans are.
If this fan serves more than one room, a vented range hood is needed in the
Bath fans are required only when the bathroom is not served by this
The principal exhaust fan must be capable of continuous ventilation (not a
Section 22.214.171.124(5) requires kitchen exhaust be filtered.
Code required range hoods must be capable of exhausting 100 cubic feet per
minute (CFM) and not exceed 3.5 Sones (Noise level). Code required bath fans
must be at least 50CFM and not exceed 2.0 Sones. Be careful with HVI labels.
An HVI label indicates the fan has been tested. It does not mean it meets
the requirements of NBC. Bath fans and range hoods that are not part of the
required ventilation do not have to meet these requirements.
Fresh air equal to 50% of the TVC is required with distribution via ducts to
all bedrooms and all levels without bedrooms. See Section 126.96.36.199. It must
be linked by controls to the principal exhuast fan and tempered (heated) to
12 degrees C before entering the living space. Make-up air is required if
protection from depressurization is necessary.Section 188.8.131.52.
F326 requires that a ventilation system be capable of providing supply air
(fresh) at least equal to the TVC.
This ventilation system must be equipped with a means to adjust the
ventilation rate to less than the TVC.
The system must provide kitchen exhaust equal to either a continuous 60 CFM
or intermittent 100 CFM.
The system must provide bathroom exhuast equal to a continuous 20 CFM or
intermittent 50 CFM.
Make-up air is required if protection from depressurization is necessary.
R2000 uses F326 as a basis for ventilation capacity and requires the items
listed above plus the following:
-TVC is the higher of the "room count" or F326 total continuous exhaust
(60CFM kitchen, 20CFM bath)
-Kitchen exhaust must be filtered.
-Actual TVC must be within 15% of calculated TVC.
-Low speed operation must be 40-60% of TVC...
In many jurisdictions in Canada, just to meet code, HRVs are mandatory.
This is to meet code. R2000 exceeds building codes. I worked on
numerous R2000 homes and even built proto type equipment for an
Advanced Home that lost government funding after an election/change of
Provincial Government. The Advanced Home Program was even 'greener' and
more energy efficient than R2000.
R2000 homes have HRVs. Please research and show me a certified R2000
home without one.
Curious you bring up F326 Installations, as they typically exceed what
ASHRAE requires. It is typically 10 CFM per habitable room, 20 cfm for
a master bedroom and 20 CFM for an unfinished basement. Works out to
about 0.3 air changes an hour usually when there are not a lot of
vaulted ceilings etc. As you state, this standard sets the ventilation
Point exhaust systems meeting F326 such as bathroom fans, range hoods,
and humidex's controlled by dehumidistats, central switches and or
timers WILL NOT cut it for a house to be R2000 certified.
R2000 homes CAN also have bathroom fans and range hoods to serve as
intermittent exhausts to disperse odors. A home could have an F326 rate
of 120 CFM, and with air being exhausted from a kitchen, a couple
baths, a laundry area etc, would mean an average exhaust rate of 30 CFM
from each area. 30 CFM from a large master bath after a mexican buffet
would take a while to clear the air, therefore exhaust fans CAN be used
for quick removal of odours.
The first link I gave clearly states R2000 homes use "state of the art"
The mechanical contractor for an R2000 home has to submit a worksheet
showing the F326 calculation and the make/model/capacity of the HRV
being installed and a report on the balancing as part of the R2000
My home town adopted this same system of forms/reports to ensure
ventialtion met F326 and this was just to meet code, not R2000. If any
appliance in the home used a B-Vent, then regular homes had to have an
I believe I gave you a typical R2000 ACH of 0.07 a while ago on another
thread, its nice to see you like demonstrate your knowledge of Blower
door rate divided by 20, you were in the ball park.
And in some parts of the US. A waste of money, IMO.
Sure. Some do, but you wrote:
No thanks. You said they all do, and I posted part of the R2K standard,
which does not require HRVs or ERVs. You were wrong. End of discussion.
Unless you'd like to argue that an HRV is cheaper to buy and run
than an exhaust fan, in an R2K house... :-)
I guess you missed the part where it states "R-2000 homes are required
to have a heat recovery ventilator (HRV)".
All you know is what you have gleaned from the internet, too funny.
Not cheaper to buy at all, just cheaper to operate. They fit right in
with all of your schemes to save energy, with the main difference being
they are proven to work.
You have to be an electrical engineer :)
I guess you can interpret the standard until you can convince yourself
that you actually know something.
Scroll down to "Mechanical ventilation beats out mould" and then scroll
further to read "In an R-2000 home, stale humid air is removed and
replaced by clean, fresh air with a mechanical ventilation system
called a heat recovery ventilator, or HRV for short."
If you had only been involved in the design of an R2000 home or had
actually seen one yourself, you would know the HRV requirement.
Instead you just give out misinformation of something you know little
Any chance you meet the following qualification? Maybe ask some one
esle who is if you do not believe me.
5.2.1 Design, Installation and Balancing of Ventilation Systems -
Mechanical ventilation systems shall be designed, installed and
balanced in accordance with CAN/CSA-F326-M91 Residential Mechanical
Ventilation Systems by an HRAI-certified Residential Mechanical
Ventilation Designer or Installer, or an R-2000-recognized equivalent.
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