Hi there. Over the past two years I built a passive house in northern Alberta Canada. My friend is a contractor who had always wanted to build one and I was very interested in building something super efficient. Anyways, he didn't know what he was doing and I was left to finish construction on my own. My HVAC guy left me high and dry and I am left with a crazy efficient house, german triple paned windows with max insulation value, max solar heat gain. On days when the sun is shining, it starts to overheat the great room of our house substancially. At -10 C, we need to have windows open when the sun is shining. Its a minor nuisance in the wintertime as we can somewhat control the temperature. In the summertime it can get unbearable. We have overhangs, plus installed solar blinds over the windows,(inside). My HVAC guy who installed hrv, isn't returning my calls as he has been paid and wants nothing more to do with job. Its 3 hours from where he's based so major inconvenience for him. I'm looking for suggestions. Options are somehow to gather that heat and save for heating later in evening, how can that be done? I'm in the country, I have an endless supply of cold water from the well so could use that through a fan coil or put a film over the windows. Anyone have any suggestions. Thanks

Exterior operable solar shades perform a heluva lot better at killing off solar gain than internal shades, which cut the light, but very little of the solar gain when you have high performance windows. An interior shade becomes the solar absorber, but it can't radiate the heat back out the window in a high-gain triple pane, so it super-heats the space between the shade & window creating a convection loop that transfers the heat indoors.

With exterior shades it radiates and convects any absorbed solar radiation to the outdoors, and blocks solar radiation from coming through the window. It's the type of product more commonly found in Arizona or Florida than northern Alberta- you won't find them locally, but internet stores ship everywhere. There are black-out versions as well as versions that allows some light to come through, and some ability to see what's going on outside.

There are many vendors- run a web search on the terms

exterior + solar + shade

An inexpensive fix, especially in summer, would be to install solar screens outside the window. These still allow you to see out, but block 80-90% of the solar heat gain.

If you are a DIY type, here is an example of the screen material and you just have to build the frame to fit your window size (there are also companies that provide this service):

https://www.homedepot.com/p/Phifer-.../100552677

Agreed.

Exterior shades/screens are your best bet for controlling your passive gain.

Interior shading/curtains won't help because at that point the thermal energy is already in the house.

Sounds like your architect didn't do all the calculations for the passive heat gain.

If your HVAC guy isn't returning your calls, spend a couple bucks to have your LAWYER send him a communication.

Then try to find someone else you can bring in to see about rectifying your HRV issues.
Or contact the HRV manufacturer, and see if they can recommend someone in your area.

Run the fan on your furnace to circulate that free heat around your house....don't waste it with a shade or open window....

“Sounds like your architect didn’t do all the calculations for passive heat gain.”

I seriously wonder if the architect did any calculations at all...

There shouldn’t be any solar heating in the Summer as the roof overhang (or some other overhang) should provide full shade then. There shouldn’t be any general solar over-heating either. The only solar over-heating that one should ever experience would only occur if you have an unusually very hot day in the Spring or Fall and even this should be buffered by the interior thermal mass and should never be excessive. I am always very saddened when I hear stories like this.

The heat can be moved by using a ventilation system or a hydronic radiant floor heating system that is specifically designed for this task.

For those who follow and subsequently read this story, this passive solar software design suite and the associated software instructions explain in detail how a passive solar design should be properly accomplished:

Borst Passive Solar Altitude Angle Software

Borst Passive Solar Roof Overhang Design Software

Borst Passive Solar Fenestration Exposure Software

Borst Passive Solar Heat Gain Software

Borst Passive Solar Thermal Mass Performance Software

If someone uses “rules of thumb” for designing your passive solar home, you should really find someone else fast!

Not to put too fine a point on it, but even with overhangs adequately shading them from direct sun massive expanses of glass can have quite a bit of heat gain from indirect scattered light. This is dead-obvious in very bright "snowscape" environments, but even "amber waves of grain" reflect quite a bit of the solar spectrum that isn't reflected by windows.

No, that is actually a very important point and ground reflectivity absolutely must be accounted for when doing the passive solar heat gain analysis. This is accomplished in the aforementioned software by using the ground reflectivity coefficient parameter.