Building insulation, heat loss, solar gain and heat transfer

When I came to Canada in mid 80’s I worked in residential building construction “learning English”. Coming from Europe where the building technologies are much different it occurred to me that there is something odd about the product of the north American building industry. I couldn't quite put my finger on it at the time.

In the 90s I built myself a house where I used some of the R2000 standard methodology.
While I did a very good job at sealing the building envelope with copious amounts of Tyvek wrap, tape, foam, caulking and vapour barrier, my efforts went only so far. The furnace was still running in the winter and A/C was churning in the summer more than I would have liked. Although better than an average Canadian home, the comfort level and overall energy use seemed less than optimal for me.
It wasn’t until about 5 years ago, when I started being preoccupied with efficiency, sustainability and alternate building technologies that I started cluing into the problems related to buildings and heat transfer.

There are 3 types of thermal transfer that we need to be cognisant of:
• Conduction
• Convection
• Radiation

Today’s North American residential buildings remind me of giant heat sinks. The technology itself doesn’t address adequately the thermal bridging phenomena where heat travels through solid materials, such as your studs, windows, etc.

If you look at the thermographic image of a building in the winter, this becomes quite apparent with the visible, warm colour contrasts depicting where the highest rates of thermal transfer take place.

There are also the thermal bridging areas that are not clearly visible. Does your basement feel cold in the winter? This is because of the heat loss through the footings, inadequate slab and basement wall insulation.

Solution:
Start with the properly insulated footings and foundation, talk to your architect, builder about super-insulating. Best money you can spend...
The more thermally efficient building envelope you have means less money you will spend on the energies and savings on scaling down your HVAC equipment. You will also experience higher comfort levels without hot or cold spots in your building. Don’t forget the high quality windows and doors to slow the heat transfer. Instead of siding, consider using stucco where the extra layer of EPS insulation reduces thermal bridging through the walls. Check out Plaston Exterior Insulation and Finish Systems by http://www.plaston.ca/ to learn more on the subject.

The roofs, Oh those shingle roofs!
Asphalt is one of the best absorbers of infrared energy. Your shingles absorb anywhere between 80-95% of thermal energy from the sun and then transfer this energy under your roof heating up the attic air. Some IR wavelengths further penetrate right into your building interior where we use more energy to cool for comfort. Sounds wasteful? It is.

The same happens with low quality or antiquated windows – solar gain further heats your interior in the summer. Walls, lacking radiant barrier are no exception and subject to the same phenomena.

Solution:
For roofing, stick with the light reflective colours and if you can, avoid the asphalt shingles altogether. Look into metal roofing systems. While they cost more, these are far more durable, last longer and reduce the radiant heat and increase your home resale value. While we are on the topic of roofs, look into proper attic ventilation and don’t forget to Google green roofs.

Radiant heat traveling through the walls can be reduced by application of radiant prevention foils, membranes and even insulation panels with silvery radiant foil already attached for easy installation.

Don’t forget to consult windows experts, make sure your windows have the correct glazing. Note, you should not have the same type of glazing on all of your windows. I highly recommend local Ottawa company Thermotech windows http://www.thermotechwindows.com/ . They have an exceptional line of windows and a great service.

Excessive building air infiltration is another weakness that costs you money. Our homes are full of smaller and larger holes that invite hot or cold air inside of your home. The problem is that it is always the opposite temperature of desired. In the winter the cold air gets in and the warm air out and in the summer it is the opposite. I read somewhere that average sum of all unintended openings equals to having a hole the size of a medicine ball whacked into the side of your home – hardly a prescription for efficiency...

Solution:
As with everything, proper planning and design is the key, but in this particular case you start with the right choice of quality doors, windows, then Stop!

Don’t let the inadequate installation to ruin the result. In the industry, improper installation is very common leading to wasted materials, time, money and can lead to water damage, mould and costly repairs.
Furthermore, It is critical that care is taken to foam every gap, tuck tape every seam and connection. Feel free to go obsessive here, you can’t go wrong...
I mentioned only a few issues, however the problem starts with an incorrect urban planning in relation to building orientation and a lack of building science in the building design. Most will agree there is a lack of quality factored in construction process where builder / building operator are two different people, so the old paradigm rules, not in favour of the owner/operator. The owner gets stuck with repair and energy bills.

Today’s energy prices are making us complacent, we just don’t feel enough pain to act and do the right thing by building energy efficient homes.

For you as the consumer it is very difficult to acquire a building that has the longevity, comfort, health benefits and beauty at the right price that you so desire and deserve!
The great news is there are economical solutions to these issues. While I touched on some at very high level, one by one, we will address these in more detail in my future blogs.

So, stay tuned and feel free to send me your comments.