One-speed versus two-speed pump?

[jbuckste]

Hi, all. I am trying to decide which pump would be better for my pool configuration. I will have a single pump running both the pool and a spa. I am most interested in cost-effectiveness and noise issues.

Thanks,

JRB

[mas985]

For pool/spa combo, a 2 speed pump is a very good choice. You can reduce your electric bill for normal circulation considerably while still having the HP for the spa jets. If you have not built the pool yet, a 2 pump option is also a possibility. Single speed pumps do have a slight edge for efficiency over 2 speed but it is not much.

[Service Guy]

Dual speed pumps are more designed for spa use only and rarely serve any purpose on a pool/spa combination. About the only time a dual speed motor would be installed on a pool/spa combination is if your were going to continue using the spa after the pool is winterized. In that case, the filter NEEDS to run whenever temps get near freezing and continue to run until the temps rise above freezing. In this part of the country that could be weeks at a time. Then, a low speed pump would be more economical. Other than that, I'd stay with a single speed pump. In addition, it'll be less expensive to replace when it dies!

[jbuckste]

Thanks Service Guy and MAS985:

My pool salesperson is recommending that we stick with a single-speed full-rated 2.5HP Pentair Whisperflo pump rather than going with a dual-speed pump. The pool will be located in Austin, TX and we may only get a couple of days of freezing or below freezing weather each year.

JRB

[Service Guy]

Pentair's single-speed WhisperFlo pump isn't available in a FULL RATED, 2.5hp. It has to be an UPRATED pump if it's 2.5hp. There's a difference. Check the specs at the bottom of this page: http://www-1.pentairwater.com/jwcs/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10001&productId=18418&langId=-1&parent_category_rn=16151&sub_category_rn=29151

[jbuckste]

Service Gui:

Yes, I am trying to get a model number from the sales rep. Aside from the model issue, do you think this single-speed pump will work better than a two-speed with my pool/spa configuration?

JRB

[mas985]

Dual speed pumps are more designed for spa use only and rarely serve any purpose on a pool/spa combination. About the only time a dual speed motor would be installed on a pool/spa combination is if your were going to continue using the spa after the pool is winterized. In that case, the filter NEEDS to run whenever temps get near freezing and continue to run until the temps rise above freezing. In this part of the country that could be weeks at a time. Then, a low speed pump would be more economical. Other than that, I'd stay with a single speed pump. In addition, it'll be less expensive to replace when it dies!


I have to disagree with this view point. Many 2 speed pumps are installed for a pool spa combo. In fact, many on this forum have that configuration. It is more cost effective to filter on a low speed when you do not need the HP for the spa jets. In a 2 speed pump, low speed is generally half the GPM but 1/3 the cost to run so net net, you are much better off for filtering on low speed.

Here is another thread on this same topic:
http://www.poolforum.com/pf2/showthread.php?t=806

[Davenj]

I have a 2 speed setup for pool and spill over spa combo. Run it on high for an hour then low for 8 and back to high for another hour. The spa drains halfway down when the pumps off. High fills it quickly and moves all the surface stuff to the skimmers. I also have a SWG that works better at low speed. I'm not forcing alot of water around the SWG thru the manifold. I like the setup and works well for me. You can hardly here the pump running on low.