This post comes with my sincere gratitude to Professor Rodrigo Mora, who heard about our project and thought it would make a good subject for his students at the BCIT Building Sciences Department, and to his students Colin Tougas and Nichole Wappel who took him up on it. I have been posting (and commenting on) Nichole’s results.
How did I get BCIT to study my house? Well, a Scout leader gave me Steve Finn’s name who heads the Sustainable Energy Manager Program who put the call out to other faculty and that’s how Rodrigo heard. Simple! Of course, I don’t know if any home reno could attract such interest. Our project was firmly in the context of the Community Home Energy Retrofit Project at the time and our stated goal is to reach for net-zero energy use when we’re done.
There is more to that story, but here at last are Nichole’s conclusions. She used data collected by sensors placed in several rooms of the house and the last one in her report was the Master Bedroom. The Conclusions and Recommendations, however, are for the whole house.
For the full BCIT story so far, click on the BCIT link in the right-hand menu.
Similar to the children’s upstairs bedroom, while the average CO2 was approximately 940ppm, higher “spikes” are regularly occurring at night time when the bedroom is occupied.
CONCLUSIONS AND RECOMMENDATIONS
In general, the average carbon dioxide concentration in the home can be considered moderate. Higher concentrations occur in the bedrooms when the house occupants go to bed; however, these concentrations decrease shortly thereafter. It appears that natural ventilation is performing adequately for most rooms of the house, with the exception of the bathroom. The bathroom appears under-ventilated, and is likely contributing significant amounts of moisture into the attic. The oil-burning furnace appears sufficient to heat the house to temperatures comfortable for the occupants.
The data analysed in this study was limited to temperature, relative humidity, and carbon dioxide concentrations. Although CO2 is often considered a good indicator of ventilation, it does not provide information on other potential contaminants in the house such as mould, pet dander, dust mites, etc.
The following recommendations should be considered for future research, and during the renovation project:
Complete air sampling and testing to check for the presence of biological contaminants.
Install an air barrier to reduce air flow from the house interior into the attic through ceiling
finishes, and provide air-tight gaskets around attic access hatches.
Renovations will require increased home airtightness to control air and moisture flow through new, highly insulated building enclosure assemblies. The existing natural ventilation strategy will likely be insufficient to provide required ventilation airflows once the house is air sealed. Other ventilation strategies should be considered, such as providing mechanical ventilation with fresh air intakes.
Thank you Nichole! You rock! Allow me to comment here on your conclusions.
After all the pains Dave-the-father-in-law and I took in 2008 to seal this leaky house, Nichole’s comment about “natural ventilation” “performing adequately” except for the bathroom made me wince. However, in a home with no mechanical ventilation system except the furnace fan which only comes on to blow warm air around, it’s good we didn’t do too good a job!
At the top of my wishlist after we take another crack at sealing the “natural ventilation” (ie: leaks) is installing a Heat Recovery Ventilator just to keep the air fresh and free of those other “potential contaminants” Nichole couldn’t measure. Heating and cooling is another question entirely.
As any good report will have, here are Nichole’s list of references. May you find them useful!
ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy 2010. American Society of Heating, Refrigeration and Air-Conditioning Engineers Inc., 1791 Tullie Circle NE, Atlanta, GA. www.ashrae.org
Birmingham & Wood. Whitehead Property – Conservation Plan. PublicLAB Research + Design.
Dales, R., Liu, Ling., Wheeler, A., Gilbert, N.L. 2008. Quality of Indoor Residential Air and Health. Canadian Medical Association Journal, Vol.179, pp.147-152.
Fisk, W.J., Satish, U., Mendell, M.J., Hotchi, T., and Sullivan, D. 2013. Is CO2 Indoor Pollutant? ASHRAE Journal, March 2013.
Sherman, M. 2004. ASHRAE’s New Residential Ventilation Standard. American Society of Heating, Refrigeration and Air-Conditioning Engineers Inc. ASHRAE Journal January 2004, pp.149-156.
Mora, R. 2014. Class Lectures Notes for BSCI 9170 – IAQ, Ventilation, and Thermal Comfort.