Can I heat my pool using PV panels? Rain harvesting and water harvesting? How to heat my pool using a heat pump?

How do I heat my pool? Heat pump vs pool solar heating vs PV panels?


(Local Auckland KW charges for power, target temp of 30 from Sept - May)


Learn how to heat your pool efficiently, call or text  02102332600 or email


When it in your pool there are many things to think about. Heating water is the hardest thing to do. The ratio to heat water and air is 1 to 3 1/2 thousand times.


When doing this you need to remember a few things. Heating a pool is like boiling a pot of water. If you give the pot of water 50% of the heat then the pot of water will never hit to its full potential. Left out the pot of water will cool very fast and the water will evaporate.


If you turn the pot of water up to 100% heat then the water will boil sufficiently. If you put a lid on the pot of water then the water will boil very fast. Not much evaporation will happen from the pot of water and you will retain the heat in the pot for a long amount of time. 


This is very similar to heating a swimming pool. 


The formula is simple, heat the pool using the sun(FREE energy), cover the pool to retain heat and stop evaporation and size the solar correctly. A minimum of 1:1 ration sqm area or more. You CAN NOT heat your pool sufficiently with 50% surface area.  


PV Panels, can I use PV panels to run my pool pump and run my heat pump for my pool?


The answer is no. 


Yes you can run the pool pump as the power required or the ask for energy from your PV panels is small or a low requirement. 


The pool heat pump is a different story.


PV for domestic power usage is fine and will work OK. Factors to take into consideration:

  • PV panels or solar powered panels have a high cost to install, usually pay back in 12 years approx
  • PV panels will only produce power(NZ) for a limited time of the year and will be for a limited amount of the day, domestic house use is ok
  • You will need to buy appliances fit for purpose for use with PV panels
  • Pool heat pumps are not designed to be energy efficient as they need to pull a large amount of energy to heat water
  • A heat pump will need to be replaced within 6 years average (As it is an appliance and it has a limited life)
  • PV panel and batteries deteriorate over time, need servicing and replacement. Price below excludes PV replacement
  • Big investment for short or limited return for pool heat pump use

e.g. of PV panels with heat pump, TARGET TEMP 26 DEGREES for 5 year period

Prices ex GST with a 4mm thermal blanket, Aug - June


  • $18,450 PV panels 14kw 
  • $7,467 Heat pump initial purchase
  • $ 2100 Cost to run heat pump - Supplimented by PV panels ($3500 @ 60%) cost per year 1
  • $ 2200 Cost to run heat pump - Supplimented by PV panels ($3500 @ 60%) cost per year 2
  • $ 2400 Cost to run heat pump - Supplimented by PV panels ($3500 @ 60%) cost per year 3
  • $ 2600 Cost to run heat pump - Supplimented by PV panels ($3500 @ 60%) cost per year 4
  • $ 2800 Cost to run heat pump - Supplimented by PV panels ($3500 @ 60%) cost per year 5
  • $7,467 Cost to replace Heat pump

Approx total 5 year period $ $43k plus GST


The requirement to draw energy from your PV panel to heat your pool is a big ask from the panels. In NZ we have a short window of sun to run the panels to drive a pool heat pump. 


Thermal pool solar heating:

Like a hose sitting on the ground in the sun with water inside. Leave it out in the sun for 5 mins, then turn the hose on. Hot or warm water will come out almost any time of the year. 


Now apply this to your pool. Put the surface area on your roof, on a platform, on a garage, os even on your fence. Cycle it slowly around the secure system, and return it to the pool. Over time the average temp of the pool will rise faster then using an appliance. 


e.g. Aug 2020(last week) in Auckland. We turned a solar system on while the pool tempo was 14 degrees. Within the day the pool got to 22 using a pool cover. The next day the pool was 24 degrees. The ambient air temp was 16 and sunny.


A similar example, we had a customer who was trying to us his heat pump. He ran it for 3 days and nights 24/7 and only hit 18 degrees. 


There was many reasons the heat pump could not push to the 24 degree target. But the simple reason was the air temp was too cool and a 10 degree ask was simply too much. 


A heat pump is a great tool to top up the temp of the pool but not do all the heavy lifting and drive the heat of your pool.


Water or rain harvesting: (Target pool temp 30 degrees)

We have recently introduced water or rain harvesting into the pool heating mix.


If you don't like to use your cover much and you don't want to pay $300 month to heat your pool(minimum power charges) then the following option is available.


Rain or water harvesting for swimming pools, spa pools or irrigation: (n.b. 3 months of the year, when rain is available)

  • Using Pool solar heating to heat your pool to 30
  • 10,000 litre rain harvest system cost to install approx $6900 - $8900 plus GST(depending on pumps, rain bank, pipe work etc)
  • Do not put the cover on the pool, letting your pool temp to lower over night and the water evaporate
  •  Simply fill your pool from your rain harvest tank system, from rain water that you collected for FREE using your down pipes
  • You get charged from the council for waste water charges, so re direct this water and save money from these charges. Use this water for your pool, spa pool, garden, washing car etc etc
  • You pool cover will come in handy to extend the swimming season even more, but the need to use the cover everyday becomes a little less

For more information call or text 02102332600 or email


We can design a solution for your pool area.