The classic way of estimating heating load in smaller, envelope-dominated buildings is to assume the rate of heat loss is proportional to the difference between the inside and outside temperature.

In last month’s column, I presented a “template” for a system that provides space heating, cooling and domestic water heating using a cold climate air-to-water heat pump as the primary heat source, and the sole source of chilled water for cooling. 

For decades, fossil-fueled boilers have dominated the market for hydronic heat sources.

Most hydronic heating systems that have renewable energy heat sources, such as solar thermal collectors, an air-to-water or geothermal heat pump or a biomass boiler also have an auxiliary heat source. 

Most of the modern hydronics technology used in North America for residential and light commercial buildings is for heating. 

I recently reviewed a project in which a municipal building was being connected to a district heating system supplied by pellet-fueled boilers. 

Whenever a hydronic system is divided into several zones, it’s worth considering a buffer tank between the heat source and distribution system.

There are sorted opinions about using expansion tanks within closed geothermal earth loops. 

I’m fortunate to be living next door to a very unique hydronic heating/cooling system.