Hydronic heat loss in one picture

by Richard Keech


I thought this picture neatly shows the limitations of passive panel-based heating such as hydronic or column heaters. The thermograph shows most of the heat convecting to the ceiling, allowing much of it to be lost before it can reach the occupants of the room. This is one of the main reasons I never recommend hydronic-panel heating.  In-slab hydronic doesn’t have this problem, but it does have other problems.



Multi-head splits vs single-split systems

There’s some debate about whether the best configuration of split systems for multiple rooms is to have multiple single splits or to use multi-splits.

By Richard Keech  2018-06-18

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Multiple single-split systems can be an eye sore


Increasingly split systems are used to heat and cool entire homes – not just single rooms.  The default way that split systems are deployed is what I call single splits – one outdoor unit piped to one indoor unit.  And repeat that configuration for each conditioned room.

The alternative, available from many vendors, is a multi-split. This configuration involves more than one ‘head’ unit for each outside unit.  Often a whole home might be served with only one (larger) outdoor unit, and heads in all bedrooms and living spaces. Continue reading “Multi-head splits vs single-split systems”

Is thermal mass over rated?

Are concrete slabs the best floor for an efficient home?

By Richard Keech 2018-06-16

Thermal mass

Figure 1: Thermal mass is a two-edged sword

Thermal mass equals efficiency?

The use of concrete slabs on ground is ubiquitous in contemporary Australian home construction. Conventional wisdom says this is a great thing for energy efficiency because of increased thermal mass.  There’s some truth to this.  However, I think the reality is not quite so simple.

Continue reading “Is thermal mass over rated?”

A spreadsheet model for efficient electric homes

Here’s a way of estimating the benefits of solar, energy efficiency and batteries in a home.

By Richard Keech, 2018-06-06

I was commissioned by the developers at The Cape to created a spreadsheet model to help understand the effect of different factors in an efficient electric home.  This lets you ask questions like:

  • How much money can I save by building a home to X stars?
  • Am I better off adding more solar panels or making the home more efficient?
  • What are my likely running costs if I have an X star home with Y kW of PV?
  • Is it worth putting in a battery system?
  • Is it possible to eliminate energy bills entirely

Continue reading “A spreadsheet model for efficient electric homes”