Lockeport Beach House wins Canadian Green Building award

Collecting solar heat from south facing windows is a great way to save money and energy on heating, and a concrete floor is one of the best surfaces to collect and store heat. But the energy gains are not nearly significant enough to be worth living on a floor that you just don’t like. You may have seen this already, but here is our page on passive heating –

Passive solar heating - how to warm your home with the sun

Even if you put a floor covering on a concrete slab floor, you will still get the temperature balancing effects of thermal mass as long as it is insulated below, and therefore kept inside your building envelope. Darker colors are ideal for absorbing heat, but within the confines of a home, the heat collection advantage of darker floors is not that pronounced. 

The reason is that once energy has entered your home (as in light through the window), it’s in. It will then either be absorbed by the floor, or reflected by the floor, in which case it will then hit another surface in your home and the heat will be partially absorbed there. Some light will be reflected towards and out the window again, but you are pretty much splitting hairs at that point.

All that is to say, don’t worry too much about the color of your floor, or by putting a floor covering over your slab that makes you more comfortable and happy.

Radiant heated floors perform best when there is nothing to slow the transfer of heat, like wood or cork flooring, but again, the effects aren’t so pronounced that you should fret about it. Best is to inform an HVAC designer ahead of time if you plan to add a floor covering so they can determine the R value and how it is affected, but at worst it will slow the delivery of heat slightly, but as long as you keep the house at a certain temperature you really wouldn’t notice much difference. Wood floors would also be more comfortable when the floor isn’t heated, due to the reduced conductivity of heat between your feet and the floor. 

Our latest demonstration house is a prefab kit house seated on a solar air heated floor with a polished concrete slab. High-performance prefab homes tend to be more affordable than site-built homes, and they are available in Ontario if you’re interested. you can see our Passive House and LEED ready prefab homes here, a few of which are oriented for passive solar heat gain, so maybe something there will meet your needs.  Here are a few more pages you may like while doing your research, hope that helps!

• Designing Homes for Human Comfort
• Passive solar Kenogami house - the most resilient house in North America
• How to choose the best windows for High Performance Homes

Low-E coatings are something we always recommend whether you’re installing double or triple glazed windows. So when you talk about having a Passive House well-designed, Low-E coatings would be a big part of that solution.

They will help reflect heat back in during the winter and help reflect heat back out in the summer. So it will save on heating and cooling costs, and if you don’t use air conditioning, when done right, it can lead to greater interior thermal comfort. We have a page that explains everything you need to know about window selection, have a read here first - 

How to choose the best windows for High Performance Homes

There is a lot to it, and it is honestly best left to those who do energy modelling. An example to look at would be our LEED V4 platinum Edelweiss House where we employed a very comprehensive passive heating and cooling strategy in our and we had different coatings on the north windows compared to the south. The south windows were a lower R-value, so they do lose more heat in the night, but the Low-E coating was chosen and applied in a way that they would gain far more heat in the day than they lost, so in the end they offer a net heat gain. north windows will offer virtually no passive heat gain, so you want the highest R-value windows possible to reduce heat loss. 

And remember that maximising your southern exposure for passive heat gain needs to include a passive cooling strategy such as overhangs or sun shades to prevent overheating in summer or you'll be spinning your wheels and spending all you heat savings on AC in the summer. That is all explained here in our  Passive solar home design video series.