Posted by Greg Grochola on 1st Feb 2019

I get asked this all the time, so I thought I might do a blog post and have it as a reference - how much warmer will a solar pool heating system make my pool. Answer: anywhere from 3.5°C to almost 16°C, it just depends on a lot of factors.

We analyzed the pool temperature increase from a 67% coverage OKU panel pool heating system (approx. equivalent to 100% coverage of an older style well spaced PVC tube system), using our new heat loading simulator (validated against the heat loading standards AS 3634-1989 and ISO TR 12596 1995 here).

We performed the calculations under various pool heat loading conditions, averaging over shoulder pool heating months only (not including peak hot summer months) for all Australian capitals.

Solar Pool Heating Water Temperature Boosts

In the table: "Shade" means shading on a pool. "Windy/Exposed" or "Sheltered" specifies the pool is either fully exposed to a windy area or fully sheltered and situated in a wind-sheltered area respectively (two extremes). "Light/DarkWalls" refers to the colour of the pool floor and walls. "Cover" refers to a bubble type transparent pool blanket, used 0%  or 100% of the time.

State Capital
Windy/Exposed
Dark Walls
No Cover
0% shaded
Wind/Sheltered
Dark Walls
No Cover
0% shaded
Wind/Sheltered
Light Walls
No Cover
0% shaded
Wind/Sheltered
Light Walls
100% Cover
0% shaded
Wind/Sheltered
Light Walls
100% Cover
50% shaded
Wind/Sheltered
Light Walls
100% Cover
100% shaded
Hobart
3.6
5.8
5.9
9.7
11.8
13.9
Melbourne
3.8
5.7
5.9
9.7
11.8
14.0
Canberra
4.4
6.3
6.5
10.6
13.3
16.1
Sydney
3.5
5.0
5.2
8.9
11.0
13.1
Perth
3.8
5.9
6.1
10.1
12.4
15.1
Adelaide
3.8
5.7
5.9
9.7
12.3
15.1
Brisbane
3.7
5.6
5.7
9.7
11.6
13.5
Darwin
3.9
5.8
5.9
10.1
12.4
14.8
Temperature boost from a 67% coverage OKU panel pool heating system

The table shows various expected temperature boosts from the use of a solar heating system in the heating months. Note: these are averages, over day and night, warm spells and cold spells.

As can be seen, a solar pool heating system is least effective in a very windy location with a pool that is fully exposed to the wind, with no blanket cover and is already heated directly with fun sun exposure with no shading and dark pool walls. On the other end of the extreme, if you don't have much sun on your pool AND you insulate using a cover AND you wind shelter your pool - then you're going to see a much larger boost from solar. Again remember these are averages; most people tend to swim in the afternoons during a hot spell, so during those time, you're going to see larger boosts.

Just as a side note, the last column of the table with wind/sheltered and 100% shading, would be roughly temperature boost an indoor pool would see at a minimum, but don't quote me on this, this is just a rank guess, we haven't run the numbers.

So there you have it, not an easy question to answer: anywhere from 3.5°C to almost 16°C.

Do you want to know how well a solar pool heating system will work for a specific set of conditions? Head over to our simulator and have a play with it :)

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