For new construction in particular, we begin by reducing the overall heat load with features such as…

• a well insulated / air tight exterior shell to reduce heat loss, 
• southern exposure (window fenestration) for solar heat gain and 
• mass (double drywall) to buffer the day time heat gain with the night time heat loss (like an adobe style house)

We use a separate small diameter duct system to pick up exhaust air from washrooms, kitchens, laundry rooms, etc, and bring it to a central air-to-air heat exchanger. 

This device (see diagram)  then recovers heat from the warm outgoing airflow and uses it to temper the incoming fresh air.  The whole thing is known as a Heat-Recovery Ventilation system, or HRV.
 

The heart of our mechanical system is the "fan/coil” connected to the supply and return air ducts for your house. This is simply a conventional furnace fan, combined with a coil like the radiator in your car. 

The fan/coil has two functions. The first is to distribute solar and internal heat gains throughout the house, including heat recovered through the HRV system.

The second is to actually heat that air when required – which means it needs a heat source.

Does that mean a furnace? 
Not necessarily.

The fact is, with all the elements we’ve designed in to reduce the load, most homes can be heated using nothing more than their domestic hot water (DHW) heater as the heat source. This way, one system provides both DHW and home heating.

Hot water from the tank is circulated through the coil. The fan then picks up this heat and distributes it through out the house. This can be supplemented by a storage tank connected to a roof top solar collectors, wood stove with water coil, etc. 

With a second coil connected to an outdoor air conditioning unit, the fan/coil unit can also be used to cool the house.

Here's how it all might look in a complete system:

You may at this point be wondering how many PhD’s it takes to operate this system. 

Luckily, it’s as simple to operate as any conventional home.  The system uses a standard thermostat, combined with an adjustable whole house sensor to control the HRV system.

Our whole-house mechanical system is completely assembled from “off the shelf” components, and any competent service person will have no trouble installing or servicing it. In fact, in our experience heating contractors are generally delighted with the simplicity and intelligence of the system.

But this is all aimed at new construction projects. What about renovations and retrofits?

Click here to see how we adapt these ideas to an existing home heated by electric baseboard heating.