14 hours ago, driver52 said:

how deep is your well out of interest? Any idea of the water temps in there?

I only ask cos I thought in the tropics the land temps were not much different to the air temps and that's why geothermal cooling systems don't make much sense

It is not particularly deep as wells go, about 10 metres.

Your statement "the land temps were not much different to the air temps" is not true in this situation. During the winter months our temperature fluctuates between around 15 degrees to 30 degrees, mainly closer to the lower end for most of the 24 hours. The land temp cannot fluctuate at the same rate and will adopt a temperature fairly close to the overnight level. In the past it hasn't lasted very long, about 6 weeks, but last year quite protracted, started much earlier about end of Oct.

Some may think that is ok but makes me shiver, particularly coming in from the garden with a sweat on.

1 hour ago, sandyf said:

The land temp cannot fluctuate at the same rate and will adopt a temperature fairly close to the overnight level

yeah it sounds like you could use the well for a 'geothermal heat pump' using coils of pipes filled with antifreeze ie for 'air con cooling' 

21 hours ago, driver52 said:

yeah it sounds like you could use the well for a 'geothermal heat pump' using coils of pipes filled with antifreeze ie for 'air con cooling' 

Sounds good in theory but the practicality would be unviable. Well is about 70 metres from the house and the feed was laid underground as the house was being built.

A note from someone that wants normal pressure, 3.5 to 4 bar for showers and garden hose.  During cold season you just reduce the flow a bit to heater to make it hot enough - no need to be stuck with a low pressure pump.  I always install a tap at input of heater (have 7) and use them to turn units on/off and adjust flow volume.