Hot water circulator pumps can be found nearly everywhere with a variety of manufacturers and options to choose from.
Many of the earlier circulator pumps worked non-stop and were more expensive to operate because they were constantly using electricity.
Fortunately, many of the current models are made with energy conservation in mind and are designed to deliver hot water on-demand, rather than running all of the time. Besides, the power of current models (high efficiency type pumps) is as low as only 5 watts, and 45 watts at max, which is less than half power consumption of the earlier pumps. Of course the high efficiency pumps are much more expensive, even more than double, but it will help you maximize your savings down the road. Besides, fortunately along with the quality of Chinese-made pumps improved, now you can get a quality Chinese-made pump of high efficiency by paying the half price of big brand pump.
Now you have already known the high efficiency pumps are the best choice for your plumbing system. In Europe, it is now a mandatory requirement for those hardware stores to sell high efficiency pumps only.
Regarding the pump housing, you could find four types material in the market, cast iron, brass, stainless steel, and plastic. For most families which only need circulator pumps for their heating system, equipped with wood pallet boiler or heat pump, the cast iron pump housing is enough, which is the cheapest. The brass/ stainless steel pump housing are usually used for the drinking water or sanitary system like shower. The plastic pump housing can usually bear 0.3MPa water pressure (1.0MPa for cast iron, brass, stainless steel), and they are mostly used on the gas boiler. The plastic housing integrate some functions of brass hydraulic group, and save the boiler cost. To be more competitive in the market, the Top 10 brand gas boiler manufacturers have already been cooperating with Chinese pump manufacturers, some with annual order quantity more than 100,000 pcs.
The circulator pump connection size could be 2”, 1 1/2”, and 1” for choice. For most houses with an area of 120 sqm, 6 meter head pump with 1 1/2” connection is enough.