Using main filter pump for solar heating is stupid?


TFP Expert
LifeTime Supporter
May 3, 2007
Pleasanton, CA
Thanks for the detailed analysis, good to have some more realistic figures! Where are you getting your IntelliFlo energy use numbers from? I couldn't find any published power use curves for IntelliFlo.
There are several agencies in the US that have databases of pump energy efficiency measurements. CEC, APSP and Energy Star are the three I use. I have a standalone DB here:

A copy of this database is also in the pump spreadsheets in my signature. Also, for the Intelliflo, they have published energy curves in the manual.

That in itself is probably a major reason to go with a single pump setup *if* the filter pump is a high quality variable speed pump (i.e. IntelliFlo).
It makes even more sense to go with a single pump if a less efficient pump is used. If all were single speed pumps, then the energy costs of a single pump is always about 1/2 that of a dual pump system. For energy efficiency reasons, it is never a good idea to go with dual pumps.

Solar pumps are typically not able to be throttled.
All pumps can have throttling valves on the return side of the pump. Throttling valves just add extra head loss to reduce the flow rate. However, for energy efficiency reasons, it is not always a good idea. You are basically reducing flow rates without reducing energy use very much.
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